| 摘要 |
PURPOSE:To produce high-purity sialon powder having fine and uniform particle size, by adding a specific amount of carbon powder to a specific powdery mixture of silica and alumina, and calcining in nitrogen atmosphere. CONSTITUTION:A mixture of a silicon alkoxide (e.g. methyl silicate) and an aluminum alkoxide (e.g. aluminum ethoxide) at an atomic ratio (Si/Al) of about 0.5-2 is dissolved in isobutanol, etc., and added with about 3-4pts.wt. of water and a small amount of ammonia water per 1pt.wt. of the alkoxide. The obtained precipitate is heated at about 500-700 deg.C for about 1-5hr to obtain a powdery mixture of silica and alumina composed of 50-80mol% silica and 50-20mol% alumina. The above powdery mixture is mixed with 16-25wt% carbon powder (preferably carbon black), and the mixture is calcined at 1,350-1,550 deg.C in nitrogen atmosphere.
|
