Preparation and Properties of Borosilicate‐Coated Alumina Particles from Alkoxides

Abstract

This paper describes the synthesis of borosilicate‐coated alumina particles. Coated particles are agglomerate‐free and contain up to 50 vol% coating. The ability to form uniform coatings is highly dependent upon both the solution chemistry and the control of the nucleation and growth of the borosilicate on the alumina. The coated particles show markedly improved densification compared to that of a mechanical mixture of borosilicate and alumina. These composite powders (borosilicate‐coated alumina particles) are moisture‐sensitive, resulting in a leached, phase‐separated, boric oxide. The particles can be stabilized by further encasing the particle with a thin layer of silica.