In the process of working, the zirconia ceramic mold effectively includes a physical dehydration process and a chemical coagulation process. The physical dehydration removes the moisture in the slurry through the capillary action of the porous gypsum mold. The chemical coagulation process is because Ca2+ generated by the dissolution of CaSO4 on the surface of the plaster mold increases the ionic strength in the slurry, causing flocculation of the slurry.
The zirconia ceramic mold is deposited on the wall of the plaster mold by physical dehydration and chemical coagulation. Grouting is suitable for the preparation of large-scale ceramic parts with complex shapes, but the quality of the blanks, including shape, density, strength, etc., is poor, workers are labor intensive and not suitable for automation.
The hot press injection molding of the zirconia ceramic mold is to mix the ceramic powder with the binder (paraffin) at a relatively high temperature (60 to 100 ° C) to obtain a slurry for hot die casting, and the slurry is under the action of compressed air. The metal mold is injected, the pressure is cooled, and the wax blank is obtained by demoulding. The wax blank is dewaxed under the protection of an inert powder to obtain a green body, and the green body is sintered at a high temperature to form a porcelain. The hot injection molded green body has good size, uniform internal structure, small mold wear and high production efficiency, and is suitable for various raw materials. The temperature of the wax paste and the mold must be strictly controlled, otherwise it will cause under-injection or deformation, so it is not suitable for manufacturing large parts, and the two-step sintering process is complicated and energy consumption is high.www.yxhgmould.com