What is porcelain? What is porcelain made from?

Kirill Sysoev

Calloused hands never get bored!

Content

Many people have a cup or figurine made of bone china at home, but few know what it is or where to buy it. This type of material is distinguished by thin-walledness, translucency and sophistication. It was designed by English ceramicist Josiah Spode. Dishes made from this material are often labeled Bone chine or Fine bone china. According to its characteristics, it occupies an average value between soft and hard material.

What is bone china

This type of porcelain refers to a special type of hard material with the addition of burnt bone. It is very durable, but at the same time white and transparent. High strength properties are achieved by melting the main ingredients during the firing process. It was created in an attempt to recreate the formula for making famous Chinese porcelain. At the end of the 18th century, bone ash began to be added to the material, and as technology developed, a basic formula was developed.

The dishes made from this material do not have the eggshell effect, which is achieved due to the fact that the voids between the particles of white clay are filled with bone ash. Thus, bone china is one of the most popular materials, which, thanks to its whiteness and transparency, has won a leading position in sales on the world market. Sets made from it can have a pleasant creamy tint.

Compound

Before ordering Chinese bone china, pay attention to the composition. The basic formula for making this type of material includes 25% each of kaolin (a special white clay) and feldspar with an admixture of quartz, and 50% burnt animal bones. The first firing is carried out at a temperature of 1200-1300 °C, and the second - 1050-1100 °C. The composition of bone ash includes about 85% calcium phosphate.

Bones that are used as part of the porcelain mass must undergo special treatment, as a result of which they begin to burn out - this is necessary to remove the glue from them and heat them to a temperature of 1000 ° C. In this case, organic substances burn, and the structure of the bones changes to the required state. From the resulting mass, using gypsum molds, objects are obtained, onto the surface of which, after firing, various designs are applied.

If necessary, the product is covered with a layer of glaze and sent back to the oven. Flowers and artistic patterns and lines are applied to the product using decal - a thin film. Painting is also used. In general, the thickness of the finished plates, cups and other kitchen utensils is less than that of a conventional porcelain base. Modern technologies provide for the replacement of biological calcium phosphate with mineral one. The quality of the dishes does not change.

Advantages

If you need bone china, it is better to buy it in a specialized online store. Some deliver by mail. Branded items have a number of advantages, due to which they gain popularity among consumers. The material has a softer color and a special whiteness, which similar materials do not have. Quality is achieved by adding ground and processed bones to the composition. Many people prefer this type of porcelain for its:

• smoothness;
• airiness;
• translucency;
• sophistication.

What is the difference between bone china and ordinary china?

This type of porcelain differs from its analogues in that a unique component is added to the composition - ground and processed animal bones. Due to the ingredient, the finished product becomes softer and its walls thinner. In the light, the material begins to shine through a little, which gives the sets an airiness and originality, an aristocratic look. Despite all its elegance, thin porcelain has good mechanical strength, making it durable.

How to store

On sale in Moscow and St. Petersburg you can find a wide range of bone-type porcelain products - tea sets, table sets, decorative vases with different decors, figurines, figurines and more. All of them have an attractive and original appearance, different shades and can last for many years due to the unique properties of the mixture. Before ordering products, please read these care tips:

• do not place items one on top of another - plates, cups, saucers, but if such a need arises, be sure to arrange each of them with napkins;
• arrange kitchen utensils so that they do not touch each other - there should be a distance between them;
• Do not wash items made of thin-walled porcelain with hard sponges or hot water;
• It is better not to use chemical detergents for washing, otherwise they may spoil the design or cause the colors of the cutlery to fade;
• products do not tolerate sudden temperature changes, so before brewing a cup of tea or coffee, preheat them - first with warm water, then a little hotter, etc.;
• When cleaning kitchen furniture, move objects made of bone material using paper napkins to prevent chipping;
• wipe the porcelain with a dry cloth, removing dust from cups, saucers, etc. as carefully as possible;
• Do not store sets near open flames - they may become deformed as a result of heating.

Major producers of bone china

The leaders among all manufacturers of products made from such porcelain are the British, who were the first to master the technique of making material with the addition of bone ash. Japanese manufacturers also have excellent skills and considerable experience in the field of creating thin-walled porcelain: they changed the established proportion of the bone component in the composition of the porcelain mass. The Japanese have developed a special formula, thanks to which the familiar technology has noticeably improved. Well-known manufacturers:

• Imperial Porcelain Factory (IPZ). It was founded in 1744 by Empress Elizabeth, daughter of Peter the Great. At that time, the plant became the first porcelain enterprise in Russia and the third in all of Europe. In the first years, small things were produced there - mostly snuff boxes for the Empress. Over time, a large forge was built and the plant began to produce larger items. The manufactory was reorganized with the accession of Catherine II. The end of the 18th century was the heyday of Russian porcelain, and IFZ became one of the leading factories in Europe. As for porcelain with bone ash in its composition, a suitable mass was first developed in Soviet times - in 1968. The first batch of this type was produced by IFZ. Now the company is the only one in Russia that produces bone porcelain mass and objects made from it.
• Royal Doulton. A company from England that has been specializing in the production of bone material for a long time and has the status of one of its largest manufacturers and suppliers. Together with the British factory Wedgwood, it is part of the alliance. Founded in 1815, the headquarters is located in Stoke-on-Trent (UK). Royal Doulton produces porcelain items of various shapes, sizes and purposes. The collections of this company are extremely popular in many countries.
• Wedgwood. Another well-known company producing bone china products. It has been supplying it to the English royal court for over 200 years. The founding of the Wedgwood brand dates back to 1759, when Yeshua Wedgwood rented a manufactory in Burslem. In addition to classic tableware, the company produces avant-garde lines, which include products of non-traditional shapes and objects of art.
• Spode. UK bone china brand with 200 years of experience. The company offers mugs, plates, sets, made to the highest quality standards. The manufactory has existed since 1770. Josiah Spode (the founder) at one time perfected the bone china formula and became the first to supply tableware for the English royal court of the 18th century. In 2009, Spode merged with Portmeirion Grou, a well-known company producing luxury porcelain.
• Narumi. A Japanese company that was founded in 1911. Its products combine modernity and tradition, West and East, unique beauty and versatility. Since 1965, Narumi began to engage in mass production of porcelain. Narumi bone china products are mostly handcrafted. The brand has become a leader in the field of luxury porcelain Bone China.

Choice

Buying an elegant porcelain product with underglaze painting requires a competent and serious approach, especially if you are going to choose an expensive handmade souvenir. In addition, it is important to distinguish a fake. A real quality creation has a pure translucent white color and shine with good strength properties. Some companies try to combine innovative solutions with traditional recipes and design. Criterias of choice:

• Material color. It should have a warm, light tint and not be too white.
• Transparency. If the product is of high quality, then its walls will transmit light well. Holding the item in your hands, you will clearly see the outline of your fingers through it.
• Study the drawing, applied to a porcelain object. It is often applied manually, so you can see characteristic strokes and brush marks.
• Please note the manufacturer. It is advisable that the back of the porcelain creation bear the markings of one of the well-known brands. If the manufacturer is unfamiliar to you, then postpone the purchase, first study all the information about it.
• It is important to make sure the object is smooth, absence of holes, inclusions, bubbles, scratches, chips on the surface and along the edges.

Where can I buy

You can purchase products made from bone china with a cool white tint at retail outlets that specialize in selling luxury tableware. Look for large stores that often run promotions that reduce the cost of goods. Visit retail outlets yourself: you will have a chance to take a good look at the items and ensure authenticity. You can order the following product from a trusted seller online. It will be good if you can agree that you will make the main payment after you have checked the goods.

Price

The cost of bone china varies greatly depending on the manufacturer and type of product. Sets with cups and saucers that are so thin that they can transmit light are in great demand. From the table you can find out the current prices for some types of bone china sets:

Video

(this porcelain is called feldspathic). The term “porcelain” in English-language literature is often applied to technical ceramics: zircon, alumina, lithium, bornocalcium and other porcelain, which reflects the high density of the corresponding special ceramic material.

Porcelain is also differentiated depending on the composition of the porcelain mass. soft And solid. Soft porcelain is different from hard not by hardness, but by the fact that when firing soft porcelain, more liquid phase is formed than when firing hard porcelain, and therefore there is a higher risk of deformation of the workpiece during firing.

Hard porcelain

Porcelain decoration methods

Porcelain is painted in two ways: underglaze painting and overglaze painting.

In underglaze painting of porcelain, paints are applied to unglazed porcelain. The porcelain piece is then coated with a transparent glaze and fired at high temperatures of up to 1350 degrees.

Decorative porcelain. Uzbek tea set

The palette of colors for overglaze painting is richer; overglaze painting is applied over glazed linen (the professional term for unpainted white porcelain) and then fired in a muffle furnace at a temperature of 780 to 850 degrees.

During firing, the paint fuses into the glaze, leaving behind a thin layer of glaze. After a good firing, paints shine (except for special matte paints used only for decorative purposes), do not have any roughness and in the future better resist the mechanical and chemical effects of acidic foods and alcohol.

Among the paints for painting porcelain, the group of paints prepared using noble metals stands out. The most common paints using gold, platinum and silver paint (or Argentine).

Gold paints with a lower percentage of gold content (10-12%) are fired at a temperature of 720 to 760 degrees (bone china is fired at a lower temperature than solid - “real” porcelain). These paints are more decorative, and products decorated with them cannot be subjected to mechanical impact (wash with abrasive agents and in the dishwasher.) Gold and silver chandeliers, polishing polish and powdered gold and silver (50-90 percent) are fired at a higher temperature along with paints . Polishing polish and powdered gold after firing have a matte appearance and are marked with an agate pencil (the pattern is applied approximately like a simple pencil on paper, only you cannot make a mistake with shading the pattern, since this cannot be corrected in any way. The master in this case must be very highly qualified) Combination matte and shiny after gold zitting creates an additional decorative effect on porcelain. Chandeliers and gold powder paints are more durable on porcelain than 10-12% gloss. However, in the entire history of the creation of porcelain and its technologies, nothing better and cheaper than decorating porcelain with gloss has been invented.

Professional overglaze painting is carried out using gum turpentine and turpentine oil. The paints are pre-soaked on the palette for a day or more. After work, they are thoroughly rubbed with the addition of turpentine oil. Turpentine in jars should be dry, slightly greasy (turpentine gradually changes from one state to another). The oil should also be more fluid and thicker. To work, take a piece of soaked paint, add oil and turpentine - and dilute the mixture to the consistency of thick sour cream. For brush stroke painting, the paint is diluted a little thicker, for pen painting - a little thinner.

It is important that the paint does not bleed from under the pen or brush. Underglaze paint is diluted with water, sugar with the addition of a small amount of glycerin.

Story

Porcelain was first produced in China. The method of its manufacture was kept secret for a long time, and only in the city did the Saxon experimenters Tschirnhaus and Böttger manage to obtain European porcelain.

Attempts to discover the secret of Oriental porcelain continued for almost two centuries in Italy, France and England. However, the result was materials that vaguely resembled porcelain and were closer to glass.

Johann Friedrich Böttger (1682-1719) began to conduct experiments in the creation of porcelain, which in 1707/1708 led to the creation of “rothes Porcelain” (red porcelain) - fine ceramics, jasper porcelain.

However, real porcelain had yet to be discovered. Chemistry as a science in its modern understanding did not yet exist. Neither in China or Japan, nor in Europe could the raw materials for the production of ceramics be determined in terms of chemical composition. The same applied to the technology used. The process of porcelain production is carefully documented in the travel accounts of missionaries and merchants, but the processes used could not be inferred from these reports. Known, for example, are the notes of the Jesuit priest Francois Xavier d'Entrecol (English) Russian , containing the secret technology of producing Chinese porcelain, made by him in 1712, but which became known to the general public only in 1735.

The understanding of the basic principle underlying the porcelain production process, namely the need to fire a mixture of different types of soil - those that are easily fused and those that are more difficult to fuse - arose as a result of long systematic experiments based on experience and knowledge of geological, metallurgical and “alchemical-chemical” relationships. It is believed that the experiments to create white porcelain took place simultaneously with the experiments to create "rothes Porcelain", since just two years later, in 1709 or 1710, white porcelain was more or less ready for production.

It should be noted that Chinese porcelain, from a modern point of view, is soft porcelain, since it contains significantly less kaolin than hard European porcelain; it is also fired at a lower temperature and is less durable.

Experts and scientists from various specialties worked together with Böttger to create solid European porcelain. European hard porcelain (pate dure) was a completely new product in the field of ceramics.

At the end of December 1707, a successful experimental firing of white porcelain was carried out. The first laboratory notes on usable porcelain mixtures date back to January 15, 1708. On April 24, 1708, an order was given to create a porcelain manufactory in Dresden. The first examples of porcelain fired in July 1708 were unglazed. By March 1709, Böttger had solved this problem, but he did not present glazed porcelain samples to the king until 1710.

In 1710, at the Easter fair in Leipzig, salable "jasper porcelain" tableware was presented, as well as examples of glazed and unglazed white porcelain.

In Russia, the secret of producing hard porcelain was rediscovered by Lomonosov's associate D.I. Vinogradov in the late 1740s. The manufactory in St. Petersburg, where he worked, eventually turned into the Imperial Porcelain Factory, better known in the USSR under the abbreviation LFZ.

The world's largest private collection of Soviet porcelain belongs to lawyer Alexander Dobrovinsky, and was exhibited in five halls of the Pushkin Museum.

see also

• Porcelain making

Notes

Literature

• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional ones). - St. Petersburg. , 1890-1907.
• Porcelain and earthenware production technology, M. , .

Links

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See what "Porcelain" is in other dictionaries:

- (Turkish farfur, fagfur, from Persian fegfur), fine ceramic products, sintered, impenetrable to water and gas, usually white, ringing, translucent in a thin layer, without pores. Porcelain appeared in China in the 4th–6th centuries: elongated slender vessels with... ... Art encyclopedia

PORCELAIN, a white, glassy, ​​non-porous, hard, translucent ceramic material. Porcelain is widely used for tableware, decorative items, laboratory equipment, and electrical insulators. Porcelain appeared... ... Scientific and technical encyclopedic dictionary

- (Turkic). 1) the title of the Chinese emperor among the Arabs. 2) a type of clay used to make the best dishes. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. PORCELAIN is the highest grade of earthenware, has hardness,... ... Dictionary of foreign words of the Russian language

- (Turkish farfur, fagfur, from Persian fegfur), a dense water and gas-tight ceramic material with high mechanical strength, thermal and chemical resistance, and electrical insulating properties. Usually obtained by sintering... ... Modern encyclopedia

- (Turkish farfur fagfur, from Persian), ceramic products (dishes, vases, figurines, architectural details, insulators, chemical equipment, etc.), obtained by sintering porcelain mass (from plastic refractory clay, kaolin, feldspar, ... ... Big Encyclopedic Dictionary

Introduction

Porcelain is the main representative of fine ceramics. The characteristic features of porcelain are white color with a bluish tint, low porosity and high strength, thermal and chemical resistance and natural decorativeness. Its features are determined by the chemical composition and structure of the shard, which depend on the purpose of the product, the conditions of their operation and the requirements placed on them.

Porcelain has high mechanical strength, chemical and thermal resistance, electrical insulating properties and is used for the manufacture of high-quality tableware, artistic, decorative and sanitary products, electrical and radio engineering parts, corrosion-resistant chemical technology devices, low-frequency insulators, etc.

Porcelain is usually produced by high-temperature firing of a fine mixture of kaolin, feldspar, quartz and plastic clay (this porcelain is called feldspar). The term “porcelain” in the English-language literature is often applied to technical ceramics: zircon, alumina, lithium, boron-calcium and other porcelain, which reflects the high density of the corresponding special ceramic material.

Porcelain is also differentiated depending on the composition of the porcelain mass into soft and hard. Soft porcelain differs from hard porcelain not in hardness, but in the fact that when firing soft porcelain, more liquid phase is formed than when firing hard porcelain, and therefore there is a higher risk of deformation of the workpiece during firing.

Hard porcelain is richer in alumina and poorer in fluxes. To obtain the required translucency and density, it requires a higher firing temperature (up to 1450 °C). Soft porcelain is more diverse in chemical composition. The firing temperature reaches 1300 °C. Soft porcelain is used primarily for the manufacture of artistic products, and hard porcelain is usually used in technology (electrical insulators) and in everyday use (dishes).

One type of soft porcelain is bone china, which contains up to 50% bone ash, as well as quartz, kaolin, etc., and is distinguished by its special whiteness, thinness and translucency.

Porcelain is usually glazed. White, matte, unglazed porcelain is called bisque. In the era of Classicism, biscuits were used as inserts in furniture products

PRODUCTION PROCESS

Preparation of raw materials

The composition of the ceramic mass and the method of its preparation are determined based on the purpose of the product, its shape and type of raw materials. The purpose of preparing raw materials is to destroy the natural structure of materials to the smallest particles to obtain a homogeneous mass and accelerate the interaction of particles in the process of porcelain formation. It is carried out mainly using a plastic method, which ensures a mass of uniform composition.

Plastic materials (clay, kaolin) are dissolved in water in paddle mixers. The resulting mass in the form of a suspension is passed through a sieve (3600 - 4900 holes per 1 cm2) and an electromagnet to remove large inclusions and ferrous impurities.

Waste materials and fluxes are sorted and freed from foreign and harmful impurities. Quartz, feldspar, pegmatite and other components are fired at a temperature of 900-1000°C. In this case, quartz undergoes polyform changes, as a result of which it cracks. This, firstly, makes grinding easier, and secondly, it allows you to remove pieces contaminated with ferrous impurities, since when fired, quartz with impurities of ferrous compounds acquires a yellow-brown color.

Rocky materials, including broken porcelain, are washed, crushed and coarsely ground on runners, and then sifted. Fine grinding is done in ball mills with porcelain or uralite balls. To intensify grinding, a surface-active additive is introduced into the mill - sulfite-alcohol stillage (from 0.5 to 1%), which, filling microcracks, has a kind of wedging effect. Grinding is carried out to a residue of 1-2% on a sieve with 10,000 holes per 1 cm2.

Plastic and lean materials, fluxes and porcelain waste are thoroughly mixed in a propeller-type mixer. The homogeneous mass is passed through a sieve and an electromagnet and dewatered in special filter presses or vacuum filters. The resulting plastic mass with a humidity of 23-25% is sent to a room with high humidity for two weeks to age. During aging, oxidative and microbiological processes occur, hydrolysis of feldspar and the formation of silicic acid, which contributes to loosening the mass, further destruction of the natural structure of the materials and increasing the plastic properties of the mass. After aging, the mass is processed on mass grinders and vacuum presses to remove air inclusions, as well as plasticity and other physical and mechanical properties necessary for the formation of products.

Types of porcelain

Depending on the composition of the porcelain mass and glaze, hard and soft porcelain are distinguished. A certain intermediate type is represented by the so-called bone china.

Hard porcelain contains mainly two starting materials: kaolin and feldspar (most often combined with white mica; melts relatively easily). Quartz or sand is added to these basic substances. The properties of porcelain depend on the proportion of two main substances: the more kaolin its mass contains, the more difficult it is to melt and the harder it is. This mixture is ground, kneaded, ground and then dried until it becomes a dough-like state. A plastic mass appears, which can either be cast in molds or turned on a potter's wheel. Finished objects are fired twice: first without glaze at a temperature of 600-800 degrees C, then with glaze at 1500 0 C. Feldspar or pegmatite is used as fluxes. “Sometimes dolomite and lime spar are additionally introduced to enhance translucency. Cover hard porcelain with a hard glaze. Thin varieties are coated with spar glaze without lime, so the products are matte, milky-cream in color. But simpler varieties are covered with a completely transparent lime glaze. Glaze and porcelain mass consist of the same substances, only in different proportions. Thanks to this, they are connected and the glaze can no longer be beaten off or peeled off.”

Hard porcelain is distinguished by its strength, strong resistance to heat and acids, impenetrability, transparency, conchoidal fracture and, finally, a clear bell sound. Invented in Europe, in 1708 in Meissen by Johann Friedrich Böttger.

Soft porcelain , also called artistic or frit, consists primarily of mixtures of glassy substances, the so-called frits, containing sand or flint, saltpeter, sea salt, soda, alum and crushed alabaster. After a certain melting time, marl containing gypsum and clay is added to this mass. In principle, this means that we are talking about a fused glassy substance with an addition of clay. This entire mass is ground and filtered, bringing it to a plastic state. The molded object is fired at 1100-1500°C, becoming dry and non-porous. The glaze is mainly made of glass, that is, from a fusible substance rich in lead oxide and also containing sand, soda, potash and lime. Already glazed products are subjected to a second firing at 1050-1100°C, when the glaze is combined with the shard. Compared to hard porcelain, soft porcelain is more transparent, the white color is even more delicate, sometimes almost creamy, but the heat resistance of this porcelain is lower. The fracture is straight, and the unglazed part in the fracture is grainy. The majority of early European porcelain was soft, as exemplified by the beautiful and highly valued products of Sevres. It was invented in the 15th century in Florence (Medici porcelain).

Bone china represents a well-known compromise between hard and soft porcelain. Its composition was discovered in England and its production began there around 1750. In addition to kaolin and feldspar, it contains lime phosphate from the burnt bone, which makes smelting easier. Bone china is fired at 1100-1500°C. So, we are essentially talking about hard porcelain, but one that is made softer by mixing the burnt bone.

Its glaze is basically the same as on soft porcelain, but contains, in addition to lead oxide, a certain amount of borax for better connection with the shard. With appropriate incandescent heat, this glaze melts and firmly bonds to the shard. In its properties, bone china occupies an intermediate position between hard and soft porcelain. It is more durable and harder than soft porcelain and less permeable, but it has in common a rather soft glaze. Its color is not as white as that of hard porcelain, but whiter than that of soft porcelain. Bone china was first used in 1748 in Bow by Thomas Fry.

From the above we can conclude; that there are three main types for the manufacture of porcelain, which differ in composition, firing temperature and are used for different types of products. Also, each type has its own glaze.

PORCELAIN PRODUCTION TECHNOLOGY

. Porcelain production

The production process for making ceramic products consists of several stages:

preparation of raw materials;

preparing the mass;

product formation, firing;

glazing and decoration.

Preparation of raw materials consists of cleaning the starting materials from impurities, thoroughly grinding, sifting, drying, etc. Preparation of the mass consists of mixing raw materials in certain proportions and stirring the mixture with water until a homogeneous liquid porcelain mass is obtained. The mass is passed through a sieve, cleaned (with an electromagnet) from iron impurities and dewatered (on filter presses or vacuum presses) to obtain molding dough.

· free forming on a potter's wheel;

· plastic molding by hand imprinting in a mold;

· plastic molding in a rotating plaster mold using a molding template or roller;

· Molding of the vessel using the circular molding method. Molding by slip casting into plaster molds;

· production of ceramic products using a combination of several molding methods.

The method of free-forming ceramic products on a potter's wheel involves the mechanical action of the potter's hands on a clay preparation in the form of plastic dough. First, the master prepares the potter's wheel for work. The first stage is the primary processing of the workpiece. Then the internal cavity of the product, the edges of the workpiece, and again the internal cavity are formed. After this, the master pulls the workpiece to the desired height. During all these operations, he rotates the potter's wheel with his foot or drive mechanism. The process ends with finishing the outer surfaces, trimming the bottom, and drying. During drying, the product can be decorated with molded parts, signets, stamped moldings.

Plastic molding by hand is carried out using plaster molds. Forms can be open or detachable; open ones are used for molding flat products; detachable - when producing products using three-dimensional models of complex shapes.

Plastic molding in a rotating plaster mold using a template or roller occurs as follows. The assembled mold, which opens into two halves, is installed in the rotating bowl of the machine. A lump of clay calculated for the volume of the product being manufactured is fed into the internal cavity of the mold. A molding template is lowered into the mold cavity, which evenly distributes the clay mass in the inside of the mold, after which it is lifted and removed from the mold. Then the mold with the product is removed from the installation machine, dried, opened, the product is removed and further processing continues (attachment of parts - spouts, handles, lids and other additional mounting).

Molding by slip casting into gypsum molds is based on the property of gypsum to absorb moisture, and the ability of clay to transform from a liquid slip into a plastic dough state when the humidity decreases. The products are formed as follows. The slip is poured into the internal cavity of the gypsum mold, resulting in a redistribution of moisture between the slip, which gives off moisture, and the gypsum mold, which absorbs this moisture. After the redistribution of moisture on the inner working surface of the gypsum mold, a layer of clay mass is formed from the slip, which turns into the state of plastic dough. When the mold has “gained” the specified thickness of the clay layer, the slip is poured out of the internal cavity of the mold, and the clay layer remains on the inner surface of the mold. This layer of thickened slip is a molded hollow ceramic product - raw. As it dries, the raw material in the mold shrinks and separates from its walls.

The production of ceramic products using a combination of several molding methods makes it possible to obtain products of complex shapes. The combination of the plastic molding method in a rotating plaster mold with a metal template or roller with slip casting and mounting of attached parts is widespread in the production of teapots, sugar bowls, cups, decanters, bowls and other porcelain and earthenware products consisting of a body and individual parts. After molding, the products are air dried and fired.

Porcelain is the same type of ceramics that is simultaneously distinguished by its snow-whiteness and elegance, as well as durability. This material has several varieties with their own characteristics - hard, soft, bone and biscuit. We will talk about the latter in more detail.

Biscuit porcelain in the narrow and broad sense

This type of porcelain, like no other, can convey the silkiness, velvety and warmth of human skin. Its structure has nothing to do with dessert - the word “biscuit” is derived from “bis”, which means “two”, “double”. This is due to the peculiarities of its firing.

In a narrow sense, a biscuit is a material that is not covered with glaze, fired once (which is more typical for modern technologies) or twice. How to distinguish bisque porcelain? It is distinguished by its snow-white, rough, matte surface, which can even be confused with high-quality varieties of marble. There is nothing to say about the technique of painting bisque porcelain - the noble material is beautiful even without applying paint or glaze.

In a broader sense, a biscuit can be called any ceramic product that has gone through only primary (otherwise known as biscuit) firing, the characteristic temperature of which is 800-1000°C. The result is a durable, heavy, but porous material. Further, repeated and even repeated firing can be carried out, as well as treatment with slip or glaze. But, as we have already mentioned, bisque porcelain figurines most often remain unglazed.

History of the biscuit

France should be called the birthplace of this noble porcelain. The work of the artist Boucher brought fame to the material, which also allowed the formation of a special style of French plastic art. In the second half of the 18th century, ceramics from workshops in the city of Sèvres, working with both glazed and bisque porcelain, also began to attract attention. These glorious works were distinguished by a floral motif - wreaths, bouquets, garlands, baskets. The works could deservedly be considered wonderful examples of art.

In the era of classicism, products made from bisque porcelain became an integral part of the interior of noble houses - furniture decor, tableware, sculptures and sculptural compositions.

Application of biscuit

Due to its porous structure, sponge cake is not used in the manufacture of dishes - the material absorbs water. However, it is very good at the following:

• Tinted porcelain of this type is used to make the faces and bodies of bisque dolls, as well as decorative masks.
• This is a popular material for sculpting sculptures, figurines, jewelry, decorative elements - everything that does not need the protection of a biscuit surface.

Other types of porcelain

Let's briefly get acquainted with other types of porcelain:

• Bone. The formula for this type of soft porcelain was discovered in England by D. Spode in the 18th century. Its unusual feature is that 60% of the material consists of the ash of burnt cow bones; hip bones are most valued here. They do not give a yellowish tint, like horse ones, and make melting easier. Its main advantage is its extraordinary subtlety, reaching the point of transparency.
• Soft. Other names: artificial, artistic, frit. It became known back in the 16th century - this is the so-called Medici porcelain. The standard formula was later invented in France in 1673. Its composition is dominated by frit - quartz, glassy substances, feldspar. Alabaster, flint, sea salt, and saltpeter give translucency and a pleasant creamy color. Soft porcelain retains heat longer, but at the same time it is characterized by porosity, low strength, and even fragility.
• Solid. Also known as "real". We owe its discovery to the German manufactory Meissen. This porcelain is distinguished by its great strength, density, resistance to high temperatures and chemical attack. The glaze looks very good on hard porcelain - it is thin and shiny. Since this coating consists of the same substances, but in a different content, than the material itself, it is uniform and tightly adheres to it. Why does the glaze from hard porcelain not flake off at all? Moreover, it will be difficult to even get her away from this material. Biscuit, by the way, is a variety of this group, only unglazed.

Biscuit looks the most natural, the warmest of all types of porcelain. That is why it is so perfect for sculptural compositions, porcelain masks and dolls.

“Beauty that will last a long time” is how porcelain is characterized by its connoisseurs. And, indeed, this material never ages, remaining perfectly smooth and white, carrying its nobility and grace from generation to generation. And the unique properties of porcelain to this day make it indispensable in the manufacture of serving dishes and interior items.

Naturally, for the extraordinary properties of porcelain. These include not only its physical, but also aesthetic qualities. The most important of them:

• real porcelain is unusually hard and durable. It is impossible to leave the point of a knife on the surface of the glaze;
• the material has increased heat resistance and can withstand high temperatures. It is not afraid of thermal shocks, which allows you to immediately place a hot object under running cold water;
• good porcelain is absolutely impenetrable. This applies to water and various gases. If the vase leaves a wet mark, it means it is earthenware, not porcelain;
• Porcelain is hygienic due to its hardness and lack of porosity. The material is resistant to food acids and alkalis, which ensures a high degree of safety for the dishes. And, indeed, porcelain and glassware are considered the most environmentally friendly;
• the high degree of plasticity of the raw material allows you to create products of various shapes, decorated with relief designs of any complexity and openwork “stucco”. This quality gives porcelain products additional beauty and value;
• uniform whiteness. White porcelain can be “warm” or “cold” tones, it all depends on the composition of the raw materials;
• melody. Different types of material sound different, but they all have a pleasant, melodic sound

The only negative property of porcelain is its fragility. The impact may cause the object to shatter or become chipped. Although some manufacturers do not break and remain intact even when the plate falls on the parquet (wooden).

What is porcelain made from?

Porcelain, what is it? The answer is simple - this is a special type of ceramic. And he began his journey in ancient China, going through various... At first these were clay cups fired over a fire, then ceramic products made from a more complex composition of clay with the addition of various impurities. With its advent, different firing temperature regimes began to be practiced, which made it possible to obtain more advanced material in terms of chemical and heat-resistant qualities. And this is porcelain.

Composition of porcelain

What is porcelain made from? The main components that are always present in this material are kaolin (50%), quartz (25%) and feldspar (25%). The numbers are, of course, arbitrary. Each manufacturer has their own “recipe” for making porcelain. Therefore, porcelain products from different factories have their own distinctive properties in appearance (whiteness, shine, transparency, sound), as well as different technical characteristics, which affects their use. For example, it is common to make sculptures, figurines, and vases from soft porcelain. Hard porcelain is ideal for tableware.