Bone china cups are made of herbivorous animal bone meal (preferably bovine bone meal) through high temperature and low temperature glaze. Generally speaking, bone china with more than 25% bone powder raw materials can be called bone china. High-quality bone china is milky white and has the characteristics of high standardization, good overall light transmission and low moisture. High-quality bone china daily-use porcelain is fired twice with high-temperature and low-temperature glaze. High-quality bone china has smooth glaze and fine porcelain quality, and has become a common utensil on people's daily dining table. At present, the bone china market is also filled with some fake bone china. What are the characteristics of bone china?
1. Mechanical strength: Although bone china belongs to soft porcelain, its mechanical strength is not low. It is a high-strength porcelain in ancient bone china, and its compressive strength is 120-160MPa, which is 80-120MPa higher than ordinary ceramics, exceeding 30%-50%.
2. Thermal stability: Because of its long cylindrical shape and high expansion coefficient, the numerical value is stable. The thermal stability of bone china is better, generally around 160°C. That is to say, the heat exchange of 160-20 ° C water will not burst once), some experts use zirconia toughening to improve thermal stability, so the thermal stability of most products is relatively good.
3. Light transmission. High-quality bone china is transparent, and the entire container is transparent when exposed to direct light. The light that passes through is white light and can be used as a lampshade. Fake bone china is partly transparent, partly opaque, and the light is yellow. If it is high-quality bone china, the light transmission part is transparent, the light transmission part is transparent, the light color is white, and it will not turn yellow.
4. Glaze surface hardness: Bone china is used on ceramic tiles and glazed at a lower temperature (1050-1150°C), so the glaze surface hardness is lower than that of ordinary ceramics, and the hardness is generally 550-600MPa. Glaze hardness can be improved by adding porcelain powder zircon powder.