Coated fused alumina particles and production process thereof

#1. Field of the Invention

#The present invention relates to fused alumina particles coated with aluminum titanate, a process for producing the same, abrasive grits of the coated fused alumina particles, and a grinding wheel and coated abrasive using said abrasive grit.

#2. Description of Related Art

#500 g of white fused alumina abrasive (WA produced by Showa Denko K. K.) with a grain size of #60 was charged in a tray of SUS304. The grain size of #60 is defined as 350 to 210 .mu.m. 1.25 g of anatase-type TiO.sub.2 powder (Ishihara Sangyo K. K., A-100; average particle size of 0.2 .mu.m, 0.25% by weight as TiO.sub.2 to 100% by weight of alumina) was dispersed in 50 ml of distilled water. The resultant 2.44 wt %-dispersion was added to and mixed with said abrasive in said tray while stirring, so as to apply the TiO.sub.2 powder to the abrasive particles.

#Then, the particles were dried in a fan drier at 60.degree. C. for 16 hours to reduce the remaining water content to 2.3% by weight.

#The powder-applied abrasive was transferred to an aluminum crucible and heated in a muffle furnace up to 1,500.degree. C. in 7 hours and kept at 1,500.degree. C. for 10 hours, followed by allowing to cool in the furnace. When the temperature in the furnace reached room temperature, the abrasive was screened with a sieve of 350 to 210 .mu.m so as to remove aggregated coarse grains and unreacted TiO.sub.2 powders. Thus, abrasive particles with a grain size of #60 were obtained.