| 摘要 |
PURPOSE:To obtain advantageously silicon carbide whiskers having an excellent crystal form while obtaining silicon nitride whiskers by treating chaff in gaseous nitrogen to form silicon nitride whiskers and treating the separated and recovered carbide residue to separate silicon carbide whiskers. CONSTITUTION:Chaff is treated with an acid, and calcined at 600-1,300 deg.C in a nonoxidizing atmosphere. The obtained material is placed in the gaseous nitrogen in a controlled atmosphere furnace at 1,300-1,450 deg.C for >=2hr to form the silicon nitride whiskers. The material is charged into a liq. mixture M (the liq. mixture of a hydrophobic org. liq., water, and hydrochloric acid), and the silicon nitride whiskers are moved separately in the water phase and the carbide residue in the hydrophobic org. liq. phase. Both materials are separately recovered. Then acid-treated chaff is added to the recovered carbide residue as an auxiliary material, and the residue is calcined in a nonoxidizing atmosphere at 1,750-1,800 deg.C for >=1hr to form the silicon carbide whiskers in the carbide residue. The material is charged into the liq. mixture M, and the silicon carbide whiskers are moved separately in the water phase and the carbide residue in the hydrophobic org. liq. phase. both materials are separately recovered. |
