Zirconia ceramics have high hardness, high wear resistance, good high temperature thermal stability and thermal shock resistance. The preparation of high-performance zirconia ceramics relies on high-quality zirconia powder and optimized sintering process parameters.
1. Preparation of high-quality zirconia powder
The preparation methods of high-quality zirconia powder mainly include physical methods and chemical methods. Physical methods include high temperature spray pyrolysis, spray inductively coupled plasma pyrolysis, and freeze drying. Chemical methods include gas phase method, liquid phase method and solid phase method. Among them, the liquid phase synthesis method is widely used because of its high efficiency, good powder particle quality and simple equipment.
2. Sintering method
The sintering process parameters mainly include sintering temperature, sintering pressure and sintering time. When different sintering processes are used for the same ceramic material, ceramic materials with very different microstructures and properties can be obtained. At present, the sintering process methods commonly used in zirconia ceramics at home and abroad include pressureless sintering, hot pressing sintering, and hot isostatic pressing sintering. and spark plasma sintering.
Pressureless sintering, also known as traditional normal pressure sintering, is to sinter prefabricated ceramic bodies under normal pressure and high temperature conditions. Hot press sintering is a sintering method in which axial pressure is applied to the powder in the mold while sintering. Spark plasma sintering (SPS), also known as plasma activated sintering, is a new type of rapid sintering technology.
