What is porcelain?
Up to now, there is not a unified understanding about what is porcelain in academic circles. But, think porcelain should have the following four conditions, everybody's understanding is consistent still.
These four conditions are:
First, the porcelain must be made of porcelain clay. China clay is a rock-like mineral that has long been used in China to make porcelain. Because of China's vast territory, Porcelain clay varies in quality, but the most important ingredient should be Kaoline. The Kaolin got its name because it was used to make porcelain in the mountains not far from Jingdezhen. In the long-term extension use, Kaolin is also used to refer to porcelain clay, has become the international common name. The different composition of porcelain clay in different parts of China makes the texture and color of porcelain vary widely, which is also the important reason for the formation of different porcelain systems. But in any case, the use of raw materials must account for a higher proportion of Kaolin, which is an important difference between porcelain and pottery.
Second, porcelain must go through 1250 degrees Celsius high-temperature baking, so that the Matrix fully sintered, compact structure. Test method is that the physical determination of the Matrix should be less than 1% of water absorption or not. The high temperature firing process is the main chemical reaction process from porcelain clay to porcelain, and is one of the key points that distinguishes porcelain from pottery.
Third, the porcelain surface should be applied high temperature firing of glass glaze. The glaze is completely melted at the standard high temperature to reach vitrification. So in the surface of the object formed a layer of non-absorbent, bright and clean protective layer, which is one of the greatest advantages of porcelain. The amount of iron oxide in the glaze and the different atmosphere in the kiln during firing result in the white, black and blue color of the finished porcelain. Adding copper, cobalt and other different elements in the glaze, the porcelain can present the beautiful colors of red, green and blue, making it colorful and beautiful.
Fourth, after porcelain sintering, matrix solid, hard, knock on the sound of clear metal. This is in fact closely related to the quality and sintering of porcelain-making raw materials. But it is an easily identifiable and intuitive standard.