Atmospheric sintering is to sinter the material under atmospheric pressure without applying pressure. It is currently the most commonly used sintering method. It includes atmospheric sintering under air conditions and atmospheric sintering under certain special gas conditions. This method has a higher sintering temperature, higher requirements in the furnace, and a greater waste of energy.
A|20g has a high melting point, so the preparation of Al2O3 ceramics often requires the addition of sintering aids to achieve compactness through liquid phase sintering. This method usually promotes the sintering of A|20g ceramics. The liquid phase sintering of Al2Og ceramics generates a liquid phase through chemical reactions. It promotes diffusion and viscous flow to achieve the particle rearrangement and mass transfer process, and reduces the sintering temperature of A|2Og ceramics. Accelerate effective sintering.
Since atmospheric sintering has no external driving force, it is very difficult to eliminate all the pores in the ceramic to reach the theoretical density. The special sintering process refers to adding sintering driving force in the sintering process of alumina ceramics to promote the densification of ceramics. At present, the common special sintering processes mainly include hot pressing sintering, hot isostatic pressing sintering, microwave heating sintering, microwave plasma sintering, spark plasma sintering and so on.