Porcelain, about

Porcelain (Turkish farfur, fağfur, from Persian. Faghfur) - kind of ceramics, impervious to water and gas. In a thin layer rayed. With a light blow with a wooden stick produces a characteristic high, clear sound. Depending on the shape and thickness, the tone is different.

Properties

Porcelain usually get hard firing fine mixture of kaolin, quartz, feldspar and plastic clay (this is called a feldspathic porcelain). The term "porcelain" in the English language is often applied to the technical ceramics: zircon, alumina, lithium, etc. bornokaltsievy porcelain, reflecting the high density of the relevant special ceramic material.

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

Hard porcelain

Hard porcelain (English) Russian., Which includes 47-66% kaolin, 25% quartz and 25% feldspar rich kaolin (alumina) and poorer fluxes. To obtain the necessary translucency and density, it requires a higher firing temperature (1400 ° C to 1460 ° C).

Soft porcelain

Soft Porcelain (English) Russian. more diverse in chemical composition and consists of 25-40% kaolin, 45% quartz and 30% feldspar. Firing temperature does not exceed 1300-1350 ° C. Soft porcelain is used primarily for the production of artworks, and the solid is usually in engineering (electrical insulators) and in daily use (dishes).
A type of soft-paste porcelain is bone china (English) Russian., Which includes up to 50% bone ash, as well as kaolin, quartz, etc., and which is particularly white, thin and transparency.
Porcelain is usually covered with icing. White, opaque, not glazed porcelain called biscuit. In the era of classicism sponge was used as inserts in furniture products .

Ways to decorate porcelain

Porcelain signs in two ways: underglaze painting and overglaze painting.
With underglaze of painting porcelain paint applied to unglazed porcelain. Then porcelain covered with transparent glaze and fired at high temperatures up to 1350 degrees.

The palette of colors glaze painting richer overglaze painting was done on glazed linen (professional term neraspisannogo white porcelain) and then fired in a muffle furnace at 780 to 850 degrees.
The cure is melted into the frosting, leaving a thin layer of frosting. Paint after a good firing shine (except special matte paint used for decorative purposes), does not have any rough edges in the future to better withstand the mechanical and chemical effects of acidic foods and alcohol.
Of paints for porcelain painting highlights a group of colors, made using precious metals. The most common colors with gold, platinum and silver paint (or Argentina).
Gold paint with a lower percentage of gold content (10-12%) are burned at a temperature of 720 to 760 degrees (bone china is fired at a lower temperature than a solid - the "real" - porcelain). These paints are more decorative, and decorated their products can not be disturbed (abrasive wash in the dishwasher.) Gold, silver chandeliers, polirgol polishing and powder gold and silver (50-90-percent) are fired at a high temperature with colors . Polirgol polishing powder and gold after firing have a matte look and entirety agate pencil (applied a pattern much like a pencil on paper, but with shading pattern can not be wrong, because then it can not be corrected in any way. Master in this case must be very skilled) Mix matte and shiny gold after diverging pattern provides additional decorative effect on porcelain. Chandeliers and gold powder paint on porcelain more resistant than 10-12% glossy. However, the history of the creation of porcelain and its technology is nothing better and cheaper decorating porcelain gloss was invented.
Professional overglaze painting done by gum turpentine and turpentine oil. Pre-soaked paint on the palette for a day or more. After working for triturated with addition of turpentine oil. Turpentine in jars should be dry, slightly greasy (turpentine is changing from one state to another). The oil also needs to be more fluid and more dense. For a piece of work is taken soaked paint, add oil, turpentine - and the mixture is diluted to a consistency of thick cream. Swipe to throw paint brush painting a little thicker, for pen painting - a little thinner.

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

Story

Porcelain was first observed at 620 in China. Method of producing the long kept secret, and only in 1708 Saxon experimenters Tschirnhausen Boettger and managed to get a European porcelain.
Attempts to unearth the secret of oriental porcelain continued for nearly two centuries in Italy, France and England. However, the result was a material that roughly resembles porcelain and closer to the glass.
Johann Friedrich Böttger (1682-1719 gg.) Began to conduct experiments in the creation of porcelain, which are 1707/1708 had led to the creation of «rothes Porcelain» (red porcelain) - fine ceramics, porcelain jasper.

However, the real china yet to open. Chemistry as a science in the modern sense did not exist. Or China or Japan or in Europe for the production of ceramic materials is not yet able to determine in terms of chemical composition. The same applies to use the technology. The process of porcelain carefully documented in the notes travel missionaries and merchants, but these reports could not be removed to use technological processes. Known, for example, notes a Jesuit priest Francois Xavier d'Antrekolya (English) Russian. Containing secret technology of Chinese porcelain made to them in 1712, but became known to the general public only in 1735.

Letter Francois Xavier d'Antrekolya on manufacturing china, 1712, published in 1735 Dyualdom
Understanding the basic principle underlying the process of porcelain, namely, the need to firing a mixture of different kinds of soil - those that are easily fused, and those that are fused more difficult - was the result of many systematic experiments based on experience and knowledge of geological, metallurgical and "alchemist chemical" relationship. It is believed that the experiments on the production of white porcelain came along with experience in creating «rothes Porcelain», since only two years later, in 1709 or 1710, white porcelain was more or less ready for manufacturing.
It should be noted that the Chinese porcelain, from the modern point of view - the soft porcelain, because it contains kaolin substantially less than in solid European porcelain, he also fired at a lower temperature and less durable.

Together with Böttger to create solid European porcelain to experts and scientists of various specialties. European hard porcelain (pate dure) was completely new product in the field of ceramics.
At the end of December 1707 was successfully pilot fired white porcelain. The first laboratory of the note on the usable porcelain mixtures refer to January 15, 1708. April 24, 1708 was ordered to create a porcelain factory in Dresden. The first samples of porcelain, the last firing in July 1708, were unglazed. By March 1709 Böttger solved this problem, but the glazed porcelain samples he had submitted to the king only in 1710.

In 1710, at the Easter fair in Leipzig presented MERCHANTABILITY dishes from the "jasper porcelain", as well as samples of glazed and unglazed porcelain.
In Russia, the secret of hard porcelain production was rediscovered University associate DI Vinogradov in the late 1740s. Manufactory in St. Petersburg, where he worked, has evolved to the Imperial Porcelain Factory, better known by the acronym USSR LFZ.
The world's largest private collection of Soviet porcelain belongs lawyer Dobrovinsky, exhibited in five halls of the Pushkin Museum.