Sintering is the last process of ceramic green body molding. For different ceramics, the sintering temperature to obtain the best effect is different. A large part of the performance of ceramic products is determined by sintering. So what factors will Affect the sintering temperature of zirconia ceramics?
Factors affecting the sintering of zirconia ceramics mainly include the particle size of the original powder, additives, sintering temperature and holding time, the choice of salts and its calcination conditions, atmosphere and molding pressure, etc., all of which have varying degrees of influence on the properties of the material.
The method of sintering zirconia ceramics, the selection of sintering method is the key to make zirconia ceramics have ideal structure and predetermined properties. A suitable sintering method can effectively reduce the sintering temperature. Al2O3 ceramics can be sintered under normal pressure above 1800°C, hot-pressed (20MPa) sintered at about 1500°C to obtain a product close to the theoretical density, and high-temperature isostatic sintered (400MPa) has reached densification at about 1000°C.
The larger the lattice energy in the crystal, the stronger the ion combination, the more difficult the ion diffusion, and the higher the required sintering temperature. The combination of various crystals is different, so the sintering temperature is also very different, even for the same crystal, the sintering temperature is not a constant value.
In the high-temperature stage of sintering, volume diffusion is the main method, while in the low-temperature stage, surface diffusion is the main method. If the material is sintered at low temperature for a long time, not only will it not cause densification, but it will change the shape of pores due to surface diffusion, which will damage the manufacturing performance. Therefore, theoretically, the analysis should increase from low temperature to high temperature as quickly as possible to create conditions for volume diffusion.
The content of zirconia in zirconia ceramics is related to the temperature suitable for sintering. Generally speaking, the higher the content of zirconia, the higher the temperature used for sintering. We can also design it to select the appropriate ceramic material. The appropriate flux can also help the sintering temperature of zirconia ceramics. come down. In the corresponding design method, zirconia ceramics will add a lot of additives, which can promote the sintering of zirconia ceramics. We can divide them into two categories, one is solid-liquid additives, and the other is liquid-phase additives.
