| abstract |
The invention provides a silicon nitride ceramic ball and a preparation method thereof, belonging to the technical field of ceramic materials. The present invention adopts the vacuum injection molding method, which can realize the forming of large-size and super-large-size silicon nitride ceramic balls with high sphericity and uniform density; the present invention adopts microwave drying, the drying speed is fast, and the deformation of the green body is small; Cold isostatic pressing of the degummed ceramic balls is beneficial to increase the density of the ceramic balls after sintering; the present invention adopts a two-step air pressure sintering process, which is beneficial to the elimination of pores inside the ceramic balls and the further improvement of the density. In the present invention, the surface and core of the large-sized and super-sized silicon nitride ceramic balls prepared by the method of injection molding combined with cold isostatic pressing and two-step gas pressure sintering have different properties such as relative density, Vickers hardness and fracture toughness. There are obvious differences, and the homogenization of the density and mechanical properties of large-sized and super-large silicon nitride ceramic balls can be achieved. |