Preparation Process Of Alumina Ceramic Powder

The alumina powder is prepared into powder material according to different product requirements and different molding processes. The particle size of the powder is less than 1μm micron, if the manufacture of high purity alumina ceramic products in addition to the alumina purity of 99%, but also need to ultrafine grinding and make its particle size distribution uniform. When using extrusion molding or injection molding, binder and plastic agent should be introduced in powder, generally thermoplastic plastic or resin with weight ratio of 10-30% The organic binder should be mixed with alumina powder at 150-200 ℃ to facilitate the molding operation. The powder materials formed by hot pressing process do not need to add binder. If the use of semi-automatic or automatic dry pressing molding, there are special technical requirements for the powder, the need to use spray granulation method to treat the powder, make it appear spherical, in order to improve the fluidity of the powder to facilitate automatic filling mold wall molding. In addition, in order to reduce the friction between the powder and the die wall, it is necessary to add 1 ~ 2% lubricant. Like stearic acid? And binder PVA.

In order to dry pressing molding, spray granulation of powder is required, in which polyvinyl alcohol is introduced as binder. In recent years, a water-soluble paraffin has been developed as a binder for spray granulation of Al2O3, which has good fluidity under heating. The powder after spray granulation must have good fluidity, loose density and friction temperature of flow Angle less than 30℃. In order to obtain higher green density, particle size ratio is ideal.