| 摘要 |
PURPOSE:To provide a guide rail for a metal heating furnace which does not make chemical reaction with metal and scale in spite of heating the metal to a specific high temp. and withstands long-period use by comprising said rail of composite ceramics essentially consisting of alumina and contg. silicon carbide particles having a specific average grain size or below. CONSTITUTION:The raw material powder which consists essentially of the alumina powder having >=98% purity and <=5mum average grain size and contains preferably 2-20wt.% silicon carbide particles consisting of fine particles having <=3mum average grain size in particular is prepd. A sintering assistant, dispersant, PVA and antifoaming agent are then added to said raw material powder and the mixture is subjected to wet process mixing, by which slip is obtd. The slip is molded by slip forging under a pressure in a gypsum mold and is then dried. The molding is sintered in a gaseous Ar atmosphere. The resultant guide rail for the metal heating furnace is chemically stable and hardly reacts chemically with the metal such as iron and scale even at a high temp. of >=1,250 deg.C.
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