Aluminum oxide wear resistant ceramics production process(1)

Alumina ceramic at present can be divided into high purity type and ordinary type two kinds.Wearproof plate type high purity alumina ceramic Al2O3 content in more than 99.9% of the ceramic material, due to the sintering temperature up to 1650-1990 ℃, the transmission wavelength of 1~ 6 microns, usually made from molten glass to replace platinum crucible: using alkali metal corrosion resistance is used as the transmission of light and sodium lamp tube;In the electronic industry can be used as a substrate integrated with high-frequency insulation.Ordinary aluminum oxide wear resistant ceramics department according to the Al2O3 content is divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain, and other varieties, sometimes Al2O3 content in 80% or 75% are classified as ordinary aluminum oxide wear resistant ceramics series.99 alumina ceramic materials used in production, resistant to high temperature crucible furnace pipe and special wear-resistant materials, such as ceramic bearings, seals and water valve, etc.;95 alumina ceramics is mainly used as corrosion resistance, abrasion resistance parts;Because in 85 China often mixed with part of talc, improved the electric properties and the mechanical strength, with molybdenum, niobium, tantalum metal sealing, some used for electric vacuum devices.

The process is as follows:

A, powder preparation: will the factory of alumina powder in accordance with the requirements for different products with different molding process preparation into powder materials.Powder particle size in microns 1 micron, if the manufacture of high purity alumina ceramic products in addition to the alumina in 99.99% purity, ultra-fine grinding and also need to make it uniform size distribution.Wear resistant ceramic plate using extrusion or injection molding, powder in the introduction of binder and plasticizer, generally for weight ratio in 10-30% of the thermoplastic plastic or organic binder and alumina powder in mixing, 150-200 ℃ temperatures for the molding operation.Adopt the hot-pressing process molding powder raw materials do not need to join the binder.If use semi-automatic or fully automatic dry pressing molding, has special technological requirements to the powder, needed by the method of spray granulation, powder processing, make its appear round ball, taking to improve liquidity powder molding automatic filling in the wall.In addition, in order to reduce the friction of powder and die wall, also need to add 1 to 2% of the lubricant, such as stearic acid and binder PVA.You would dry pressing molding will be on powder spray granulation, including introducing polyvinyl alcohol as binder.In recent years on a sea research institute to develop a water-soluble paraffin wax as the binder of Al2O3 spray granulation, under the condition of heating has good liquidity.After spray granulation powder must have good liquidity, loose density, flow Angle of friction temperature is less than 30 ℃.Grain size ratio of ideal conditions, such as to get a larger grain density.