Production process of zirconia ceramics

The production of zirconia ceramics requires the preparation of high-purity, well dispersed, ultrafine particles and narrow particle size distribution powders. There are many methods for the preparation of zirconia ultrafine powders. The purification of zirconia mainly includes chlorination and thermal decomposition, alkali metal oxidation decomposition, lime melting, plasma arc, precipitation, colloid, hydrolysis, spray pyrolysis, etc.

Production process of zirconia ceramics:

1. Injection molding

The forming process of grouting molding includes physical dehydration process and chemical coagulation process. Physical dehydration removes water in the slurry through the capillary action of porous gypsum mold. The chemical coagulation process is because the Ca2+generated by the dissolution of CaSO4 on the surface of gypsum mold increases the Ionic strength in the slurry, causing the slurry flocculation. Under the action of physical dehydration and chemical coagulation, ceramic powder particles are deposited and formed on the gypsum mold wall.

2. Hot Die Casting Forming

Hot press casting is the process of mixing ceramic powder with a binder (paraffin) at a high temperature (60-100 ℃) to obtain a slurry for hot press casting. The slurry is injected into a metal mold under the action of compressed air, cooled under pressure, and demolded to obtain a wax billet. The wax billet is dewaxed under the protection of inert powder to obtain a plain billet, which is then sintered into porcelain at high temperature. The green body formed by hot press casting has precise dimensions, uniform internal structure, less mold wear, high production efficiency, and is suitable for various raw materials.

3. Casting forming

Tape casting molding is the process of fully mixing ceramic powder with a large amount of organic binders, plasticizers, dispersants, etc. to obtain a viscous slurry that can flow. The slurry is added to the hopper of the tape casting machine, and the thickness is controlled by a scraper. It flows out to the conveyor belt through the feeding nozzle, and is dried to obtain a film blank.

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