Alumina ceramics occupy a large proportion in living ceramics and industrial ceramics, especially in power plants, cement plants, ports, mines and other heavy wear fields, high-purity alumina ceramics are more favored, but the melting point of alumina is as high as 2020, sintering is extremely difficult, how to reduce the sintering temperature without affecting the performance of alumina has been a research topic for many manufacturers, so what are the factors that affect the sintering temperature of alumina?
1.Sintering method: direct sintering, it is very difficult to burn alumina to a molten state, as the temperature rises, the energy consumption will increase sharply, and the requirements for the sintering kiln, sintering environment, etc. will be higher and higher, and the sintering cost will also increase sharply. In order to solve this problem, wear-resistant ceramic manufacturers such as Jingcheng Special Porcelain use powder metallurgy technology to reduce the sintering temperature of alumina to below 1700, which greatly reduces the difficulty of sintering and reduces the cost. On this basis, the atmospheric pressure sintering temperature of alumina ceramics is above 1800, the hot pressing (20MPa) sintering is about 1500 to obtain products close to the theoretical density, and the high-temperature isostatic sintering (400MPa) has reached densification at about 1000.
2.Auxiliaries: Auxiliaries are usually added to reduce the sintering temperature during the sintering process, and the selection of reasonable additives can also effectively reduce the sintering temperature.
3.Embryo body forming method: The embryo body forming method can eliminate the defects of the embryo body to a certain extent, so that the microstructure of the embryo body is evenly distributed, and the phases are evenly distributed, which affects the temperature required for sintering. Therefore, choosing the appropriate embryo body forming method can also reduce the sintering temperature.
4.Powder particle size: the powder sintering process is used to calcine the alumina sintering temperature and the powder particle size is also related, Jingcheng special porcelain is to use the method of long-term grinding to make the alumina powder more fine and more uniform, so that you can obtain better quality alumina products at the same sintering temperature.
In addition, the gas composition and environmental humidity in the kiln will also affect the alumina sintering temperature, and it is necessary to combine these factors and use them rationally to reduce the sintering temperature and improve the quality of alumina ceramics.