Preparation Of Nano Alumina Abrasive

Nano alumina abrasive has a comprehensive potential in application. Its performance is superior to SG abrasive. Aluminum hydroxide, the precursor of alumina, was synthesized by precipitation reaction of aluminum nitrate and sal volatile. The effects of the final pH value, the additive amount of dispersant, and the aluminum nitrate concentration on particle size of ultra-fine alumina powders were studied systematically. The influences of doping nano alumina seed, magnesia and silicon dioxide with the precursor on the sintering characters and microstructure of the nano alumina abrasive were discussed. Sintering process, powder treatment process as well as doping methods also had effects on particle size, single particle strength and the sintering characters of the alumina. Suitable process for nano alumina abrasive sintering was optimized. Properties of samples were tested and analyzed by TG-DTA, BET, TEM, SEM, laser particle analyzer and single particle tester. The single particle strength of nano alumina abrasive and conventional white alumina, imported SG abrasives was contrasted.The results showed that dispersant amount, aluminum nitrate concentration and pH value of solution played significant roles in the particle size of nano alumina. The suitable preparation condition for nano alumina abrasive was as follows: the precursor of nano alumina was synthesized when the react temperature=45℃, pH=5, content of dispersant=1.0% and aluminium nitrate concentration=0.1mol/L and with additions ofα-alumina seed, magnesia and silicon dioxide. Dryed grains after isostatic pressed at 220MPa was sintered at 1450℃for two hours. The abrasive, with a relative density of 99.4%, average particle size of 100nm and single particle strength of 23.52N, was obtained.The single particle strength was better than those of white alumina abrasive and SG abrasive.