Alumina particles, production process thereof, composition comprising the particles and alumina slurry for polishing

Abstract

Alumina particles obtained from aluminum chloride by a gas phase method, the alumina having an amorphous form or a crystalline form of transition alumina, with primary particles thereof having an average particle diameter of approximately 5 to 100 nm, and secondary particles, resulting from the aggregation of the primary particles, having an average particle diameter of approximately 150 to 800 nm and wherein the particles having a secondary particle diameter larger than 45 μm are contained in an amount of about 0.05% by mass or less.

1 . Alumina particles obtained from aluminum chloride by a gas phase method, said alumina having an amorphous form or a crystalline form of transition alumina, with primary particles thereof having an average particle diameter of approximately 5 to 100 nm, and secondary particles, resulting from the aggregation of said primary particles, having an average particle diameter of approximately 150 to 800 nm and wherein the particles having a secondary particle diameter larger than 45 μm are contained in an amount of about 0.05% by mass or less.  
     
     
         2 . Alumina particles obtained from aluminum chloride by a gas phase method, said particles having a crystalline form of δ or θ or a mixed form thereof.  
     
     
         3 . A composition comprising the alumina particles as set forth in  claim 1 .  
     
     
         4 . A composition comprising the alumina particles as set forth in  claim 2 .  
     
     
         5 . An alumina slurry for polishing, comprising the alumina particles as set forth in  claim 1 .  
     
     
         6 . An alumina slurry for polishing, comprising the alumina particles as set forth in  claim 2.