What products are called ceramics. What is made of ceramics? Drying and firing the product in the oven

Ceramics is one of the oldest materials used to make tableware and other products. It has a number of positive properties: strength, heat resistance, environmental and chemical safety, products from it have a high aesthetic potential, which determines its widespread use.

Ceramics are products made of clay (or clay substances) with or without mineral additives, obtained by molding and subsequent firing. To improve consumer aesthetic properties, ceramics are coated with glaze.

The materials used in the production of ceramics are usually subdivided into plastic materials: clays (polymineral rocks consisting of kaolinite, soda, silicon oxides, feldspar, iron, etc.); kaolin (a monomineral rock composed of kaolinite); emaciated materials - reduce shrinkage during drying and firing: quartz sand, alumina, broken porcelain and faience, fireclay; sludge - reduce the sintering temperature and create a glassy phase (feldspar and pegmatite); materials for glaze.

The factors that form the consumer properties and quality of ceramic household goods are the same as for glassware: the type of ceramics, the method of molding and the type of decoration.

Depending on the structure, a distinction is made between fine ceramics (glassy or fine-grained shard) and coarse (coarse-grained shards). The main types of fine ceramics are: porcelain, semi-porcelain, earthenware, majolica, and rough pottery.

Porcelain - has a dense sintered shard of white color (sometimes with a bluish tint) with low water absorption (up to 0.2%), emits a high melodic sound upon impact, and can shine through in thin layers. Due to the paired firing of products, the edge of the side or the base of the product is not covered with glaze.

Distinguish between hard and soft porcelain. Hard porcelain is used for the production of tableware and tea and coffee tableware for everyday use. Soft porcelain can be: biscuit (not covered with glaze, used for the production of artistic and decorative products), bone (bone meal is introduced into the composition, resembles white marble in appearance, is characterized by high whiteness and transparency, is used for the production of tea and coffee tableware of a festive assortment ), feldspar ("thin-walled", similar in properties and purpose to bone, but its white color has a bluish tint); low-temperature ("frit" - heat-resistant, mechanically strong, usually it is covered with colored glazes, abroad one of the main types of ceramics for the production of everyday dishes).

The raw materials for the production of porcelain are kaolin, sand, feldspar and other additives.

In terms of properties, semi-porcelain occupies an intermediate position between porcelain and earthenware, its shard is white, water absorption is 3 ~ 5%, it is used in the production of household utensils.

Faience has a white shard with a yellowish tint, the porosity of the shard is 9-12%. Due to the high porosity, earthenware products are completely covered with colorless glaze. The glaze has low heat resistance, therefore given view ceramics is used in the production of everyday tableware. It is produced from white-burning clays with the addition of chalk and quartz sand.

Majolica has a porous shard (water absorption of about 15%), products have a smooth surface, high gloss, small wall thickness (as determined by the molding method - casting), they are covered with colored glazes, they can have decorative embossed decorations. For the production of majolica, white-burning clays (faience majolica) or red-burning clays (pottery majolica), floodplain, chalk, quartz sand are used.

Pottery - the shard has a red-brown color (red-burning clays are used), high porosity (water absorption up to 18%). Products can be covered with colorless glazes, painted with colored clay paints - engobes. The assortment is represented by kitchen and household utensils (pots for roasts, jugs for milk) and decorative items.

The process of manufacturing ceramic household goods in a simplified form can be represented by the following stages: preparation of raw materials; obtaining a ceramic mass; molding of products; drying and straightening; burning; glazing; decoration.

The main methods of molding ceramic products are: plastic molding method; casting, semi-dry pressing.

When molding products by a plastic method, a ceramic mass with a moisture content of 22-24% is used, the formation is carried out on automatic machines or semi-automatic machines. In this method, the ceramic mass is placed on the bottom of the mold and rolled out with a template, and a product is formed in the gap between the mold and the template. Use this method to obtain products from hard porcelain, faience, pottery.

The casting method involves the use of ceramic mass (slip) with a moisture content of 32-36% (creamy consistency), which is poured into porous gypsum or polyvinyl chloride molds. This method is used to produce products from soft porcelain (except for frit), hard porcelain (products of complex shape), majolica.

For flat products of a simple shape, a semi-dry pressing method is used. At the same time, the ceramic mass has a residual moisture content of 2-3%; pressing is carried out in metal molds. This method is used in the production of products from earthenware, semi-porcelain, low-temperature porcelain. The advantages of this method are an increase in the production rate and a reduction in energy costs (drying and straightening processes are excluded), but it is used for a limited number of types of products: small plates, saucers, etc.

The final ceramic is formed during the firing process. There are two types of firing: solid and watered. The hard firing precedes the glaze, thus forming a sodden-resistant shard. The watered firing is carried out after glazing in order to form the glaze structure.

When decorating ceramic household goods, a number of methods are used: painting, decoration in the form of stripes, stencil, silk-screen printing, decal. Specific types of decorating ceramic household goods include the following:

Coverage - coating the surface of the product with paints (distinguish between solid; partial; with cleaning; with cleaning and finishing; descending and ascending) using an airbrush, stencil, special templates;

Stamp - a small one-color surface pattern applied by paints and gold preparations using rubber stamps or tapes; it is usually used in combination with other types of jewelry;

Printing - a contour drawing formed by dots, dashes, strokes (ink from printing is transferred to the product, or first to tissue paper, and then to the product); monochromatic drawings, can be overglaze and underglaze, supplemented with painting (with painting), stencil;

Photo for ceramics - used for decorative (gift) products;

Decorations with decorative glazes: colored, flowing, crystal, matte, lace, luster, crackle.

Embossed embellishments: openwork board, cut edge, embossed board (and their combinations); decorative reliefs;

Additional decorations with paints and a preparation of gold: smear - continuous coating of a product element; mottling - a partial sketch (smear), emphasizing individual elements of the product.

All drawings, according to the nature of their location on the product, are subdivided into side ones; solid; a bouquet (up to three sculptures); spreading with a large bouquet; a medallion (a drawing framed in the form of a circle, oval, polygon); arabesque (narrow side ornamental pattern).

Decorations can be overglaze and underglaze. Most types of surface film decorations are fired.

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Introduction

Ceramics (other Greek kEsbmpt - clay) are products made of inorganic materials (for example, clay) and their mixtures with mineral additives, made under the influence of high temperatures with subsequent cooling.

In a narrow sense, the word ceramics means clay that has been fired.

The earliest ceramics were used as dishes made of clay or mixtures of it with other materials. Currently, ceramics is used as a material in industry (mechanical engineering, instrumentation, aviation, etc.), construction, art, and is widely used in medicine and science. In the 20th century, new ceramic materials were created for use in the semiconductor industry and other fields.

Modern high-temperature superconducting materials are also ceramics.

1. Types of ceramics

Depending on the structure, a distinction is made between fine ceramics (glassy or fine-grained shard) and coarse (coarse-grained shards). The main types of fine ceramics are porcelain, semi-porcelain, stoneware, faience, majolica. The main type of coarse ceramics is pottery ceramics.In addition, there are carbide, alumina, zirconium, nitride ceramics.

Porcelain has a dense sintered shard of white color (sometimes with a bluish tint) with low water absorption (up to 0.2%), when tapped, it emits a high melodic sound, and can shine through in thin layers. The glaze does not cover the edge of the bead or base of the porcelain product. Raw materials for porcelain - kaolin, sand, feldspar and other additives. Faience has a porous white shard with a yellowish tinge, the porosity of the shard is 9 - 12%. Due to the high porosity, earthenware products are completely covered with a colorless glaze of low heat resistance. Faience is used for the production of tableware for everyday use. Raw materials for the production of faience are white-burning clays with the addition of chalk and quartz sand.

In terms of properties, semi-porcelain occupies an intermediate position between porcelain and earthenware, the shard is white, water absorption is 3 - 5%, it is used in the manufacture of tableware.

Majolica has a porous shard, water absorption is about 15%, products have a smooth surface, shine, small wall thickness, are covered with colored glazes and may have decorative embossed decorations. For the manufacture of majolica, casting is used. Raw materials - white-burning clays (faience majolica) or red-burning clays (pottery majolica), floodplain, chalk, quartz sand

Pottery has a shard of red-brown color (red-burning clays are used), high porosity, water absorption up to 18%. Products can be coated with colorless glazes, painted with colored clay paints - engobes.

2. Historical overview

ceramics industry medicine high temperature

Clay has devotedly served humanity throughout its long history. At first glance, completely unattractive, she was indispensable in many areas labor activity person. The plasticity of clay, its ability to turn into a durable and waterproof material after firing, attracted human attention to it back in the Mesolithic era, 10-16 thousand years BC. e.

Archaeological excavations carried out on the territory of many countries of Europe, Africa, Asia, America confirm the widespread development of ceramic craft. In the monuments of material culture that have come down to us, you can find remarkable beauty products for household use: dishes, jewelry, all kinds of figurines of animals, birds and many other items.

The first clay products were fragile and very afraid of moisture, so only grain and other dry foods could be stored in them. But one day, while removing the ashes of an extinguished fire, a man noticed that the clay soil, which he always took for making household items, became as strong as stone under the influence of heat. Since then, people have begun to burn clay products to give them strength. The miraculous transformation of clay is called “ceramics”, which means “clay” in Greek.

The firing discovery made pottery ancient man practical. Ceramic products were then made by means of molding, tape, spiral-rope - they were laid one on top of the other in a spiral. During the late Neolithic period, about 4 thousand years BC. e., ceramic vessels began to be decorated with ornaments, in which motifs of a circle and a spiral prevailed, denoting the sun, moon, lightning and other magical powers, and covered with multicolored patterns. Such products were found in the south-west of our country (Tripoli culture), the countries of Central Asia, the Middle East, the Mediterranean and other regions of the world.

Narrow-necked jugs, a variety of double vessels reminiscent of modern binoculars, and deep bowls painted with black, red and white clay are examples of the ceramic craftsmanship of that period. Already at that time, ceramics achieved great artistic expression. It was only with the invention of the potter's wheel (4th - early 3rd millennium BC) that the process of making ceramics was greatly simplified, and labor productivity increased.

The potter's wheel was the greatest achievement that made it possible to create symmetrical, uniformly expanding or, conversely, narrowing products of various shapes. From wet, well-mixed clay, an experienced potter could make a pot, cup or other necessary thing in a few minutes. A piece of clay in his hands was flattened, stretched, the walls of the vessel rose, became thinner and acquired a conceived shape. After that, the products were fired in pits dug in the ground or brick ovens. Soft, plastic clay turned into a hard shard.

Pottery masters gradually discovered the secrets of clay: they figured out its types, learned how to make recipes for clay masses, invented glaze, and invented new, more economical forms of products. Applying simple techniques of processing clay, simple equipment, they created genuine works of art with great taste and virtuosity.

Modern ceramic production is equipped with sophisticated equipment, uses new dyes and finishing techniques. Of course, at home it is impossible and there is no need to copy it. But you can create products that are simple in manufacturing technology. They will keep the warmth of your hands, your love for this ancient, but forever young kind of creativity.

Ceramics has been known since ancient times and is probably the first material created by man. It was believed that the emergence of ceramics is directly related to the transition of a person to a sedentary lifestyle, so it happened much later than baskets. Not long ago, the first pottery specimens known to us belonged to the Upper Paleolithic era (Gravettian culture). The oldest item made of baked clay dates back to 29-25 millennia BC. This is Vestonice Venus, which is kept in the Moravian Museum in Brno.

Found in 1993, pots from Sanzhendong Cave ( english) in the Jiangxi province in the southeast of the PRC were molded 20-19 thousand years ago. Shards from a pointed vessel found in Yuchanyan Cave ( english) in the Hunan province in southeastern China, date back to 18.3-17.5 thousand years ago.

In the Mesolithic cultures, ceramics are used irregularly and, as a rule, at a later stage; the most perfect examples of Mesolithic ceramics are known in the Jomon culture in Japan. In the Neolithic, ceramics became an integral attribute of almost all archaeological cultures (with the exception of the period of the most ancient agrarian communities of the Pre-Pottery Neolithic in the Middle East, when the transition to a sedentary lifestyle took place before many other technological innovations).

The pottery was originally molded by hand. The invention of the potter's wheel in the third millennium BC (Late Eneolithic - Early Bronze Age) made it possible to significantly speed up and simplify the process of forming the product. In the pre-Columbian cultures of America, Indian ceramics were made without a potter's wheel until the arrival of Europeans.

Certain types of ceramics were formed gradually as they improved. production processes, depending on the properties of raw materials and the resulting processing conditions.

The oldest types of ceramics are various vessels, as well as spinning wheels, weaving weights and other objects. This household ceramics was ennobled in different ways - relief was applied by stamping, tracing, and stuck-on elements. The vessels received different colors depending on the firing method. They could be polished, painted or painted with ornaments, covered with engobe, glossy layer (Greek ceramics and Roman Terra sigillata), colored glaze ("Hafnerceramics" of the Renaissance).

By the end of the 16th century, majolica appeared in Europe (depending on the origin, it is also often called faience). Possessing a porous shard of iron and lime, but at the same time white earthenware mass, it was covered with two glazes: an opaque, high tin content, and a transparent, shiny lead glaze.

The decor was painted on majolica over raw glaze before being fired at a temperature of about 1000 ° C. Paints for painting were taken of the same chemical composition as the glaze, but their essential part was metal oxides that withstand high temperatures (the so-called refractory paints - blue, green, yellow and purple). Starting from the 18th century, the so-called muffle paints began to be used, which were applied to the already fired glaze. They are also used for painting porcelain.

In the 16th century, the production of stoneware pottery spread in Germany. White (for example, in Siegburg) or colored (for example, in Rehren), a very dense shard consisted of clay mixed with feldspar and other substances. After firing at a temperature of 1200-1280 ° C, the stoneware became hard and practically non-porous. In Holland, red stoneware was produced after the model of Chinese ceramics, and the same feature is found in Boettger's pottery.

Stoneware was also produced by Wedgwood in England. Thin faience as a special kind of pottery with a white porous shard covered with white glaze appeared in England in the first half of the 18th century. Faience, depending on the strength of the shard, is divided into soft, thin faience with a high lime content, medium - with a lower lime content, and hard - completely free of lime. This last shard often resembles stoneware or porcelain in composition and strength.

Pottery can be divided into two groups: unglazed and glazed ceramics. The first group includes terracotta and pottery, the oldest of all types of ceramics. Terracotta - in Italian "burnt earth". It is fired clay, not covered with glaze. Previously, sculptures, beads, and reliefs were made from it. Nowadays, this type of ceramics is rarely used.

Pottery ceramics requires additional processing. To make it waterproof, it is smoothed before firing with any smooth object (“veneer”), compacting the outer layer of clay until a peculiar shine appears. "Staining" consists in long-term exposure of clay products in the smoke of a slowly cooling furnace. A very ancient method of processing is “steaming”, or “scalding”: a product taken out of the oven is immersed in water with flour. At the same time, beautiful tan marks form on its surface, the dishes become waterproof. Currently, pottery ceramics are very widespread. Pots, cups, jugs and other household items are made from it. And they are valued no less than porcelain and glass ones.

The second group includes glazed (or glazed) ceramics. It is covered with a layer of glaze, enamel and fired again. The glaze made the pieces waterproof and allowed the potters to decorate them: the matte, velvety surface alternates with glittering glaze streaks. Under the glaze, painting with engobes looks good - liquid clays painted in different colors. Engobing is an ancient type of processing of clay surfaces, but it is still widely used.

The closest relative of pottery is majolica. This word comes from the name of the Mediterranean island of Mallorca, where this type of pottery originated. Majolica is the name for pottery clay products covered with colored glazes - enamels.

Faience... Its basis is white clay. It is easy to distinguish an earthenware jug from a majolica one, you just have to pay attention to the bottom: the protrusions on it are dark for pottery ceramics, and white for earthenware. What distinguishes earthenware from majolica, brings it closer to porcelain, but earthenware does not possess the whiteness and transparency of porcelain, its shard is porous and less durable. Earthenware products have thick, opaque walls of soft, streamlined shapes. It is especially beautiful when a creamy shard shines through through a transparent green, purple or brown glaze.

In Russia, faience production reached high development in the 18th century. Talented and original folk craftsmen from Gzhel and other centers of ceramic crafts took an honorable place in the history of Russian decorative and applied arts.

Homeland porcelain is China. Due to its high strength, absolute whiteness of the shard, richness of colors, chemical resistance, it significantly surpassed all European ceramics. To create porcelain, a very high firing temperature is required - up to 1400 ° C and a clay mass of complex composition, including kaolin, feldspar sand and other additives. Porcelain was highly valued and ceramists of European countries fought to unravel the so-called "Chinese secret", but all their attempts ended in vain. And in 1709 mountains in Meissen (Saxony) a dense, translucent, absolutely white porcelain shard was obtained. By the end of the 18th century, porcelain making was mastered throughout the European continent.

In Russia, porcelain was invented by a friend of MV Lomonosov, the chemist DI Vinogradov.

During the search for the secret of making porcelain in many countries, their own varieties of porcelain ceramics were created: in Germany - a red refractory mass, in England - a stone mass called "Wedgwood porcelain" (named after the inventor and owner of the plant D. Wedgwood), in France - soft frit porcelain.

The next and last type of ceramics is fireclay... It is a ceramic battle mixed with clay. Chamotte has a coarse-grained composition, the glaze spreads on its surface in spots, without completely covering it, which gives the chamotte product a special originality. It is highly prized by the artists who introduced it to the arts and crafts field.

3. Ceramics in Russia

The oldest ceramic ware (12 thousand years ago) in Russia was found in the Transbaikalia and the Far East (see Siberian Neolithic)

Transparent ceramics

Historically, ceramic materials have been opaque due to the nature of their structure. However, sintering nanosized particles made it possible to create transparent ceramic materials with properties (range of operating radiation wavelengths, dispersion, refractive index) that lie outside the standard range of values \u200b\u200bfor optical glasses.

4. Nanoceramics

Ceramic nanostructured material (eng. Nanoceramics) - a compact material based on oxides, carbides, nitrides, borides and other inorganic compounds, consisting of crystallites (grains) with an average size of up to 100 nm. Nanoceramics are used for the production of armored ceramics, microwave oscillator lamps, substrates for semiconductor devices, insulators for vacuum interrupting chambers, power semiconductor devices and electron-optical converters in night vision devices.

Ceramic production technology

1. Slip preparation;

2. Forming the product;

4. Preparation of glaze and glaze (enameling)

Raw materials for ceramic masses are divided into plastic (clay and kaolin) and non-plastic. Chamotte and quartz additives reduce shrinkage of products and the likelihood of cracking during the forming stage. Lead red lead and borax are used as glass formers.

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What is ceramic tile and what is it made of?

Ceramic tiles are fired clay plates. Most often they come in square and rectangular shapes, but they can be made in the form of a complex geometric mosaic. It can be used to decorate walls and floors both indoors and outdoors.

  1. Abrasion resistance is one of the most important qualities of floor tiles, which characterizes the resistance of the tile to abrasion and the ability to maintain appearance without changes. There is a classification of PEI includes five groups: PEI I - for walls in bathrooms, PEI II - for walls / floors in bedrooms, offices, bathrooms, PEI III fits in any residential premises and in small offices that do not have a direct entrance from streets, PEI IV is suitable for any living room, as well as for covering stairs, hallways, corridors, PEI V is used both in private and public interiors with above average traffic (offices, shops, cafes, restaurants). For places with heavy traffic (traffic), it is recommended to use unglazed porcelain stoneware (airports, train stations, shopping centers).
  2. Water absorption is the ratio of the mass of water absorbed by the sample when it is completely immersed in water to the mass of dry matter. The ratio is expressed as a percentage. The water absorption of glazed ceramic floor tiles should not exceed 3%, while tiles with a water absorption of more than 10% can only be used on indoor walls. Tile water absorption rate plays important role when facing swimming pools. For this, it is necessary to use only special tiles, such as porcelain stoneware or clinker.

  3. Frost resistance - the ability of tiles to resist temperature changes. The durability of ceramic tiles is determined by two parameters: the presence and the number of pores. The double-fired tile is rather porous and therefore not frost resistant. A single-fired tile with a water absorption of less than 3% is considered frost-resistant. Unlike ceramic tiles, porcelain stoneware has a minimum level of water absorption - less than 0.05%.
  4. Cracking is the appearance of fine cracks in the enamel coating. This happens with low-quality or incorrectly selected tiles under the influence of sudden temperature changes. This defect is sometimes present on tiles prior to laying. When tiles crack some time after installation, improper tile installation can be the cause: use of poor mortar or glue, too thick or thin layer of these materials.
  5. Slip resistance is a characteristic that determines the ability of a surface to prevent an object on it from sliding. This property is a basic requirement for the safety of residential and industrial premises, as well as for outdoor flooring. In baths, saunas and swimming pools, ribbed tiles with grooves are usually laid.
  6. Chemical resistance is a characteristic of tile enamel, reflecting its ability to withstand contact with acids, salts, household chemicals at room temperature. It must resist the aggressive or mechanical effects of these substances, without undergoing external changes. The tile can be protected by filling it with epoxy materials that resist chemical attack well.
  7. Tone and caliber. Hue - the color saturation of the tile, which may slightly differ from the declared color. It is indicated on the package by a number or letter. Caliber - the actual size of the tile, which sometimes differs from the nominal by a couple of millimeters. The caliber is indicated on the packaging next to the nominal size. During production, the tiles are sorted into batches of the same size and tone with the tolerance of the difference established by the standards.

  8. Bending resistance. The higher it is, the lower the water absorption of the tile. Porcelain stoneware has a very high bending resistance, while porous tiles are lower.
  9. Tensile strength is the level of possible load that the tile must withstand. It directly depends on its thickness. The ability to withstand loads is especially important for floor tiles. Such loads as the weight of a person or furniture, the tiled flooring must withstand easily and not break.
  10. Surface hardness is a characteristic that expresses the ability of a surface to resist scratches and damage. Scratches are clearly visible on the shiny surface of the tile, while on the matte surface they are less noticeable.

Ceramics

CERAMICS -and; m. [greek. keramikē]

1. Pottery production, pottery art. Specialize in ceramics.

2. collect. Fired clay products. Antique K. Exhibition of ceramics.

3. Specialist. The mass from which such products are made. Ceramic products.

◁ Ceramic, th, th. K-th products. K-th vase. Number of tiles. K. plant, workshop. Ceramic, th, th. K-th production.

ceramics

(Greek keramikē - pottery, from kéramos - clay), products and materials obtained by sintering clays and their mixtures with mineral additives, as well as metal oxides and other inorganic compounds (carbides, borides, nitrides, silicides, etc.). The structure distinguishes rough ceramics (building, fireclay bricks, etc.), thin with a homogeneous fine-grained structure (porcelain, piezo- and ferroelectric ceramics, cermets, etc.), porous with a fine-grained structure (faience, terracotta, majolica, etc.), highly porous (thermal insulation ceramic materials). By application, ceramics are divided into construction (bricks, tiles, facing tiles, etc.), household and sanitary (dishes, art products, washbasins), chemically resistant (pipes, parts of chemical equipment), electrical, radio engineering, thermal insulation (expanded clay, foam ceramics, etc.), refractories. Pottery has been known since the Neolithic (the first finds are in the 8th millennium BC in Ganj Dar, Iran).

CERAMICS

CERAMICS (Greek keramike - pottery, from keramos - clay), an extensive group of dielectric materials, united by a common technological cycle. At present, the word ceramics is understood not only as clay-containing, but also other inorganic materials with similar properties, in the manufacture of products from which high-temperature firing is required.
Ceramics composition
Ceramic material consists of several phases. The main phases are crystalline (one or more) and glassy. The crystalline phase determines the characteristic properties of a ceramic material and represents chemical compounds or solid solutions of these compounds. The main physical properties of ceramics - electrical, piezoelectric, magnetic, temperature coefficient of linear expansion, mechanical strength - largely depend on the characteristics of the crystalline phase. The vitreous phase is in the ceramic material in the form of interlayers connecting the crystalline phase. The amount of vitreous phase and its composition determine mainly the technological properties of ceramics - sintering temperature, the degree of plasticity of the ceramic mass during molding. The density, degree of porosity and hygroscopicity of the material also depend on the content of the glassy phase. The presence of a gas phase (gases are in closed pores) is due to the method of processing the mass and leads to a decrease in the mechanical and electrical strength of ceramic products, and also causes dielectric losses at increased field strengths due to ionization of gas inclusions. The pores degrade the properties of the ceramic, especially at high humidity.
The advantage of ceramics is the ability to obtain predetermined characteristics by changing the composition of the mass and production technology. Ceramic materials due to such properties as high heat resistance, lack of hygroscopicity in most materials, good electrical (piezoelectric, ferroelectric) and magnetic characteristics with sufficient mechanical strength, stability of characteristics and reliability, resistance to high energy radiation and the use of fairly cheap and affordable raw materials ensured their wide application in various fields.
Depending on the purpose of ceramics, obtaining the desired properties of products is achieved by the selection of raw materials and additives and the features of the technology. The main raw materials in the ceramic industry are clays (cm. CLAY) and kaolin (cm. KAOLIN) due to their wide distribution and valuable technological properties. The most important component of the initial mass in the production of fine ceramics is feldspars. (cm. FELD SPARS) (mainly microline) and quartz (cm. QUARTZ)... However, the increased and sharply differentiated requirements for ceramics by metallurgy, electrical engineering and instrument making have led to the development of the production of various types of technical ceramics based on pure oxides, carbides and various compounds.
Ceramics production.
The technological scheme of ceramic production as mandatory includes the following operations:
- fine grinding and thorough mixing of the initial components;
- plasticization of the mass and the formation of a molding semi-finished product;
- molding of workpieces from plasticized mass;
- sintering of products (high-temperature firing).
Grinding and mixing of raw materials is carried out in ball and vibrating mills. Grinding can be "dry" or "wet". All crushed ceramic masses are divided into three groups according to their technological characteristics: plastic masses (materials containing a significant amount of clay substances in the charge), low-plastic masses (materials with a small amount of clay substances), non-plastic masses (materials from a clay-free charge). Charge composition (cm. SHIKHTA) largely determines the technology of preparing the mass for molding.
The resulting batch is plasticized with an organic plasticizer (cm. PLASTIFIERS).
Shaping of products is carried out by pressing, plastic broaching (extrusion) through a mouthpiece or hot injection molding. The choice of the molding method is determined by technical, economic and technological factors, the main of which are the shape, size and accuracy of the part, the number of parts produced and the technological properties of the applied masses.
For example, large-sized items of complex configuration are formed by casting a liquid ceramic mass (water slip) into plaster molds, which are broken when the blanks are removed. Mainly, household porcelain and faience are molded from plastics in plaster molds on semiautomatic and automatic machines. Sanitary-building ceramics of complex configuration are cast in plaster molds from ceramic slip on mechanized conveyor lines. Radio and piezoceramics (cm. PIEZOCERAMIC), cermets (cm. CERMETS) and other types of technical ceramics, depending on their size and shape, are made mainly by pressing from powdery masses or by casting from paraffin slip in steel molds.
Pressing consists in obtaining a product from a free-flowing mass under the influence of external pressure. Pressing can be "semi-dry isostatic", "wet", "hydrostatic", "hot". Hot pressing is used for the manufacture of non-porous products with a controlled grain size (up to 0.1 microns), characterized by increased strength and density, which improves, for example, in the case of ferroceramics, the magnetic characteristics: magnetic permeability, induction, magnetization reversal time. This method is especially suitable for the manufacture of ferrites for magnetic heads of devices for magnetic recording and reproduction of sound and video signals, microwave ferrites and piezoelectric ceramics, which cannot be produced by conventional methods. Products molded in one way or another are dried in chamber, tunnel or conveyor dryers.
Sintering of products is carried out in muffle or tunnel electric furnaces at a temperature of 1300 ° C and above. During sintering, the plasticizer burns out, chemical reactions between the components are completed. Due to the fusion of particles, the shape of the product is fixed, the material acquires the necessary mechanical strength and the specified physical and electrical properties. Depending on the composition of the material, sintering (firing) can be carried out not only in an oxidizing environment, but also in a neutral and even in a reducing environment. Ceramic firing is the most important technological processproviding a given degree of sintering. Precise adherence to the firing regime ensures the required phase composition and all the most important properties of the ceramic. In the process of firing, due to moisture evaporation, burnout of the plasticizer and compaction of the material, the products shrink, i.e. a decrease in their size, but their mechanical strength and density increase. In accordance with the set of requirements, the degree of sintering different types ceramics varies widely. Before firing, articles made of electric porcelain, earthenware and other types of fine ceramics are coated with glaze, which melts at high firing temperatures (1000-1400 ° C), forming a glassy water and gas impermeable layer.
By application, ceramics are divided into building ceramics, household and sanitary-technical (dishes, art products, washbasins) ceramics, chemically resistant ceramics, electrical ceramics, radio engineering ceramics, thermal insulation ceramics (expanded clay (cm. KERAMZIT), foam ceramics (cm. FOAM CERAMICS) and others) and refractories.
The structure distinguishes rough ceramics (building, fireclay bricks, etc.), thin with a homogeneous fine-grained structure (porcelain (cm. PORCELAIN), piezo- and ferroceramics, cermets and others), porous with a fine-grained structure (faience (cm. FAYANCE (ceramics)), terracotta (cm. TERRACOTTA), majolica (cm. MAJOLICA) and others), highly porous (heat-insulating ceramic materials).
HISTORY OF CERAMICS The oldest ceramics
The first clay figurines appear in ancient Paleolithic times (cm. PALEOLITH) (about 27 thousand BC). Earthen vessels appeared somewhat later, in which water and food were stored. At the same time, there were attempts to use fired clay.
Already in the Neolithic era (cm. NEOLITHIC) firing is widespread. In different parts of the Earth, similar products are created, still clumsy, sculpted with fingerprints, mostly open forms, with thick walls. The original vessels everywhere had a sharp or rounded bottom, they were placed between the stones of the hearth. In the Late Paleolithic, vessels with a flat bottom appear. Products are decorated with sculpted ornaments. Gradually, ceramics of different localities takes on a variety of shapes and ornaments. Pottery from this period is an important archaeological feature of cultures, which are often named after the predominant type of ornament.
In 6 thousand BC. e. in a number of regions painted ceramics predominate (Samarra culture in Central Mesopotamia, Aegean ceramics). Glossy ceramics of excellent quality (brown and red, strictly black tones) appeared. Ceramic figurines in the Aegean world perfectly convey the grace of the Kor girls. During the same period, ceramics was used as a building material.
In the Bronze Age in the states of Mesopotamia and Egypt, artisans began to use the potter's wheel, making ceramics becomes a hereditary profession. Thanks to the opening of the glaze (cm. GLAZE) porous vessels became watertight, and the variety of colors and decorations obtained with the help of colored glaze turned pottery into works of art. In China, thanks to the use of quality white clay - kaolin (cm. KAOLIN) already in 2-1 millennium BC. e. thin-walled glazed dishes were made. In Ancient Egypt in the 2nd millennium BC. e. faience appears (cm. FAYANCE (ceramics)).
Fine fired pottery is used to decorate buildings (Ishtar gate (cm. ISHTAR) in babylon (cm. BABYLON)). Harappan civilization (cm. HARAPPIAN CIVILIZATION) uses brick tiles for paving floors.
Antique ceramics
Painted ceramics of Ancient Greece had a huge impact on the development of the entire world of decorative and applied art. Various types of ancient Greek vases (amphorae, hydrias, cilicas, craters) are widely known, decorated with elaborate floral patterns, which are then replaced by carpet, or orientalizing (cm. ORIENTALIZING STYLE), style - ornament with polychrome belts of images of animals and fantastic creatures.
In the 6th century. BC e. the so-called black-figure (black-gloss) style is formed, in which silhouette images were applied with black varnish on yellow or red clay, details of clothing, ornaments were made with white and purple paints.
The composition of the painting was based on the expressiveness of black silhouettes, outlined by a thin generalized line. A little later, the red-figure vase painting appeared, preserving the natural color of the clay in the images of the figures when the background was filled with black varnish. This technique gave the master the opportunity to draw shapes in more detail, conveying the natural movement of the figure.
Greek ceramic plastics have also reached a high level of development. Expressive female figurines made of terracotta (cm. TERRACOTTA) in Tanagra, recreate the images of ancient Greek women, their daily activities, the exquisite fashion of ancient Greece.
Roman ceramics did not reach such heights as ancient Greek, but left their mark on the art of ceramics. Not painting, but relief was the favorite technique of the Aretium masters - the center for the manufacture of pottery in ancient Rome. Vessels with relief ornaments covered with transparent glaze were widespread here. Roman builders widely use ceramics, they make complex architectural details from it.
Ceramics of the Far East
The oldest clay products found in China date back to 3 thousand BC. e. Already in the 4-5 centuries. earthenware products were manufactured in China. But China became famous primarily for the invention of porcelain. (cm. PORCELAIN), which appeared as a result of improving the technology of making ceramics in the 6th century. From the 14th century. one of the main centers for the manufacture of Chinese porcelain has become Jingdezhen, the region of occurrence of kaolin, feldspar (cm. FELD SPARS)as well as especially clean sand. Chinese vases and tableware are distinguished by technical and artistic perfection, an extraordinary richness of forms and decor. They served as a model for later European production.
In the 14th century. reached its peak and Korean ceramics, decorated with inlay of black and white clay, as well as porcelain with reliefs and floral patterns. With the formation in Japan in the second half of the 14th century. the cult of the tea ceremony, porous vessels and bowls of raku-yaki made of heavy ceramic mass appeared here. Seto stood out among the Japanese ceramic centers, where they produced items with transparent glazes. Japanese porcelain was especially delicate.
Ceramics of the Middle and Near East
The impetus for the development of artistic ceramics in the countries of the Middle and Near East, most likely, was the Chinese porcelain imported at the turn of the 8-9 centuries. In Mesopotamia, Egypt, Turkey and especially Persia, they created excellent ceramic utensils. The vessels were especially distinguished by their painted chandeliers. (cm. CHANDELIER), finely turned objects with turquoise glaze from the Persian city of Kashan, intricate minai-style items from ancient Ragi (now Rei in Iran), blue and white ceramics from the Turkish city of Iznik.
Western European ceramics
In Western Europe, ceramics began to develop intensively during the Renaissance (cm. RENAISSANCE (Renaissance))... Ceramics from Arab countries, especially from the Moorish part of Spain, had a great influence. Influenced by the Spanish tin-glazed pottery known as the Spanish-Moorish ware (center of manufacture - Valencia), at the end of the 14th century. in Italy (in the cities of Faenza, Urbino, Gubbio), the production of such ceramics began to develop intensively, but already under the name "majolica" (cm. MAJOLICA)... Coating the items with white pewter glaze created the ideal background for painting. In turn, Italian majolica paid considerable attention to the development of majolica in Germany in the 15th century, as well as in France (especially in Nevers) in the 16th and 18th centuries, where it became known as "faience".
In the Netherlands (Delft), similar ceramics were made from the middle of the 16th century. English pottery with pewter glaze in the spirit of Dutch products, produced during the 17th and 18th centuries, was called "Delftware". Later, more utilitarian items were produced by the English ceramic Lambeth factory - pharmaceutical jugs, wine bottles, water flasks.
Lead-glazed ceramics, which can be easily painted in various colors, are also widely known. It reached its peak in France in the 17th century. - the famous thinnest vessels from Saint-Porcher and "country clays" - decorative dishes covered with irrigation by Bernard Palissy (cm. PALISSY Bernard).
Stone mass was another technological type of ceramics at that time. (cm. STONE MASS)... The primacy in its invention belongs to the German potters of the 14th century. Nuremberg, Hoechst, Nymphenburg, Ludwigsburg became the centers for the production of stone products. German ceramics came to England. Staffordshire craftsmen improved the stone mass and obtained a more durable shard.
The greatest success was achieved by the English ceramist J. Wedgwood (cm. WEDGWOOD Josiah), who, on the basis of stone mass, invented better quality earthenware masses - basalt shard, cream mass and "jasper mass", from which the famous blue vases with white relief in the classicism style were made (cm. CLASSICISM).
A true revolution in the history of Western European ceramics was the invention in the early 18th century. by German chemist Johann Bötger (cm. BETGER Johann Friedrich) porcelain. Soon a manufactory was opened in the Saxon town of Meissen, which began to produce one of the most valuable porcelain in the world - Meissen (cm. MEISSEN PORCELAIN)... Porcelain from Meissen became famous for its graceful subject figurines, sets, vases, and toilet utensils.
From the middle of the 18th century. Sevres porcelain began to dominate in Europe (cm. SEVRSKY PORCELAIN), produced in the French city of Sevres. The predecessor of the Sevres manufactory was a small factory in Vincennes near Paris, specializing in the casting of porcelain flowers in the Rococo style (cm. ROCOCO)... In 1756, the Vincennes factory moved to Sevres, where the exquisite and sophisticated style of Sevres porcelain was finally formed. Along with painted gilded plastic, they created figurines from white unglazed porcelain - biscuit (cm. BISCUIT).
High quality English porcelain has also gained worldwide recognition. In the 18th century. Britain almost excelled in the number of ceramic factories: Worcester, Chelsea, Derby, Spode, Coleport, Bow, Minton. Each of them was distinguished by its own handwriting and style.
Russian ceramics
After the decline during the Tatar-Mongol yoke, Russian ceramics in the 14-15th centuries. reborn again. In the 18th century. along with pottery handicrafts, majolica tableware with painting on raw enamel began to be produced, in particular at the Moscow factory of A.K. Grebenshchikov, founded in 1724. The production of tiles was established (cm. TILES) - first embossed, then smooth with painting.
In 1744 the Porcelain Manufactory was founded in St. Petersburg, where three years later D.I. Vinogradov (cm. VINOGRADOV Dmitry Ivanovich) the production of Russian porcelain was started. In 1765, the manufactory received a higher status and became known as the Imperial Porcelain Factory. (cm. IMPERIAL PORCELAIN FACTORY), where from the end of the 18th century. produced wonderful sets, vases, portrait busts in the style of early classicism, and later in the Empire style (cm. AMPIR)... From the day of its foundation, the plant worked on the orders of the imperial court. For more mass production in 1766 at Verbilki F. Gardner (cm. GARDNER Franz Yakovlevich) founds a private factory, famous for its genre figurines and high quality tableware. In the village of Gzhel (cm. GZHEL) in the suburbs in the 1830-1840s. there are many businesses that take advantage of the local clay. At the end of the 19th century. the largest private factories pass into the hands of the entrepreneur M.S.Kuznetsov (cm. KUZNETSOV Matvey Sidorovich) (including the Gardner factory). His factory in Dulevo produced mass products from faience and porcelain of fairly good quality.
Ceramics of the 20th century
Already from the end of the 19th century. The works of ceramists in most countries are marked by the search for a new style: the desire to reveal the natural beauty of the ceramic mass, or, conversely, to give it a sophisticated urbanity. Art Nouveau porcelain became famous (cm. MODERN), manufactured at a plant in Copenhagen.
In a number of countries, stylization of folk art, characteristic of modernity, manifested itself, a return to handicrafts. Many painters and sculptors turn to ceramics. In Abramtsev's workshops (cm. ABRAMTSEVO) ceramics takes on new forms, a new color (primarily in the works of M.A. Vrubel (cm. VRUBEL Mikhail Alexandrovich)). The attention to decorative and applied decoration characteristic of Art Nouveau leads to the widespread use of ceramics in the decoration of buildings and interiors.
Functionalist designers, starting in the 1920s, sought new simple forms, cleared of unnecessary decorativeness and suitable for mass production. Special attention was given to revealing the texture of the material. Technologies are developing: new types of glaze and enamels appear. Large panels and small ceramic sculptures are made by almost all major artists of the 20th century. The panels by F. Leger are especially famous (cm. Lege Fernand)... Ceramics are becoming an important part of interiors.
The development of technology and the rise in living standards lead to the fact that ceramics is becoming a rather massive hobby; many have their own kilns. In the works of many ceramic artists, there is a noticeable desire to combine Western styles with Eastern traditions and technologies. In the USSR, the Baltic republics were especially famous for their ceramics.
In 1953 the International Academy of Ceramics was organized in Geneva (Switzerland).

Making ceramics is easy! By knowing the basics, you can start creating your product in no time. The process may seem daunting at first, but once you have accumulated enough experience and knowledge, you will have enough skill. Here is pretty much everything you need to know to get started making pottery.

Steps

The basics

    Choose a method. It is important to do this first, as the method determines the type of clay you will be working with. Don't rule out the choice of clays that require a baking - if you are serious about this hobby, you can buy a small home oven. The following is a summary of the methods and their corresponding clay varieties:

  1. Choose your clay. After choosing the method you will use, you can choose the type of clay. Most clays require oven baking, but most newer grades can be oven baked. If you just want to play with wet clay, don't even worry about firing it. Rule of thumb: Wet and dry clays won't work together - be sure to make sure the clays have the same consistency.

    • If you are going to fire clay, choose between high temperature and low temperature firing.
      • Low temperature firing is most suitable for bright colors and detailed ornaments. The glazes are very stable at this temperature, the colors remain bright and do not shift during the firing process. The disadvantages are that the products are not completely vitrified (the clay is not fully fused), so you have to rely on the glaze to make the product waterproof. This makes such products less suitable for use as dishes or for storing water. Since the glaze has not interacted with the ceramics, as is the case with high-temperature firing, there is a high probability of glaze chipping. However, when using the right clay and glaze, the glaze can be quite durable. The clay used in low temperature firing is called pottery.
      • In medium and high temperature firing, clays are used, called fine stone or porcelain. Vivid colors can still be obtained in oxidizing ovens (electric) and to a lesser extent in reducing ovens (gas). After firing at temperatures where the product itself is waterproof, greater strength is achieved and such products can be used as tableware or oven dishes. Porcelain can be made very thin and still have sufficient strength. At these temperatures, the glaze interacts with the clay shard to create variegated and unique pieces that many people find interesting. Typically, the glaze is displaced (significantly or slightly), so the detailed design will be blurry.

  2. Prepare yourself and prepare your workplace. Working with clay can be a mess, especially if children are involved. Cover areas that you do not want to contaminate: lay tarps or newspapers on the floor, or work in a garage or non-residential area.

    • Never work in clothes that you are afraid to get dirty. If you have long hair, tie it in the back. This will make them less dirty and will not get into your eyes.

    Forming on a potter's wheel

    Prepare your clay. Air bubbles can be disastrous for an otherwise perfect product, so get rid of them before you start. Knead or roll the clay with your hands in small portions - start with a portion that fits in both of your palms.

    • Knead the clay like dough, form a ball out of it and hit it on top of plaster of Paris (it absorbs moisture well). Repeat the operation several times until the bubbles disappear. If you are not sure if there are bubbles left, use a wire to split the ball in half and inspect it.

  3. Start a circle. With a little effort, throw the clay into the center of the circle. Since you are just starting out, use an amount no more than a large handful of clay for now. Moisten your hands in a bowl of water, which should be placed close, and begin to mold the clay.

    • Start pulling the clay mass up. Grasp the clay with your hands and begin to squeeze upward.
      • Whenever you work with clay, make sure your elbows are pressed against your inner thighs or knees, whichever is more comfortable for you. This will help keep your hands firmly in place when you work.

  4. Center the clay. Using this method, the clay is unwound to a perfectly smooth state, without bumps and beats. Once you get the cone, you are ready to move on.

    • Press in the tower with one hand and hold it with the other. If you are right-handed, press the tower with your right hand: the main force is from the top.
    • Once the clay looks like a wide lump near the surface of the circle, start flattening the sides by applying pressure to them. Some clay may collect on your left hand - just set it aside.

  5. Shape the product. Specific instructions at this stage end - each product (plate, pot, etc.) needs to be molded in a different way. But regardless of the type of product, do it with deliberate and slow movements - before you complete each movement, the circle should make about 5 revolutions. All 360-degree clay must receive the same finish to make the product round. Remove accumulated water with a sponge.

    • When you're done, clean the piece with a wooden knife and smooth the surface with a scraper.
      • Note that if things go awry and you mess up the mud, then you shouldn't try to make a lump out of it and try to repeat everything. The clay will not accept the required thickness a second time and will not be molded in the future.

    Hand molding

    1. Make sure there are no bubbles in the clay. If you put a workpiece made of clay with bubbles in the oven, then there is a possibility that it will explode. As described in Shaping on a potter's wheel, hit the clay by placing it on plaster of paris (it absorbs moisture) and roll it out like dough.

      • If, to be sure, you want to check the mass from the inside, then take a wire and cut the mass in half. If bubbles persist, continue working.

    2. Use pinch, tape, or formation techniques. Three techniques can be used to sculpt pottery. Products obtained using each of the techniques have their own characteristic appearance. The reservoir method is best suited for large items.

      Applying glaze

      1. Burn the clay at least once. After that, you can apply glaze on it! Access your kiln if you don't have your own, and let the professionals take care of the rest. If you have your own oven, then be sure to double-check that you can work correctly with it and find out what the requirements of your product are.

        • Different clays react differently to heat. Read the instructions on the clay packaging and do a little research online. Also consider the dimensions of your item.

      2. Choose a frosting. As with any step, there are many options. Each type of glaze will have its own special look.

        • Slip: You can buy slip-shaped glazes and underglaze paints, which are usually made to be applied with a brush. All you need to apply this glaze is a brush. Some glazes are difficult to apply with a brush and produce a smooth finish; as a result, marks will remain on the product. Others will melt well enough for the brush marks to disappear.
        • Dry: You can purchase glazes in powder form, which are typically formulated for dipping, pouring or spraying. In addition to a brush, you will need a bucket, some water, something to stir, and a mask to avoid inhaling dust. The advantage of dipping is that you can get a more uniform glaze, and you can do interesting tricks that cannot be done with a brush, such as double dipping, which allows you to get different colors on the same piece. More advanced people apply glaze by spraying, as it requires good ventilation, a spray gun, a compressor, an application booth, etc.
        • DIY: This is the most advanced form of frosting. Based on the recipes, you buy your own raw materials and mix them. Among other things, you will need recipes that can be found in books and on websites. You will also need the chemicals from which the frostings, scales, sieve, and experimenter's spirit are derived. Sometimes your frostings will not work well. You will need to learn how to modify these glazes to solve problems in your path. Sometimes the results will be amazing.
        • Be sure to dry the clay completely before firing it. Otherwise, it may crack or explode.
        • When carving patterns in the clay, wait until it is as hard as leather. Also, do not "scratch" by making deep, fine cuts. Make the cuts wide enough for their depth.
        • If you work on a product for several days, store it under a plastic bag overnight to avoid drying out too quickly.
        • Clay forgives flaws, but from working with it with prolonged contact with water or with significant manipulations, you can get tired and lose your mood.
        • Always dry the clay completely before firing. The moisture in the clay turns into steam, which, when released from the clay, causes the pot to explode.
        • An easy way to make small animals is to make small balls and connect them, and then iron the attachment points.
        • Sometimes college will give you enough clay to play a little. You may even be allowed to work in their studio.
        • Ideally, you need to find someone with at least a little experience to teach you. This is a very practice dependent process, so it is important to have someone by your side who can lead you by example and interact with you. This manual is intended as a reminder or rough guide, but in reality each sculptor has a different hand position.

 

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