| 摘要 |
PURPOSE:To improve the service life of the alumina carbon type sliding nozzle plate by adding calcium hexaboride into raw materials of refractories at specific weight % or below. CONSTITUTION:The calcium hexaboride (CaB6) powder having <=0.1mm grain size is compounded with the whole refractories at <=5wt% of the entire part thereof. CaC2 and various kinds of borides and oxide are formed by a chemical reaction at a high temp. at the time of compounding alumina, carbon, metallic silicon powder, metallic aluminum powder and a phenol resin of a binder and molding the mixture to a prescribed shape, then calcining the mixture. The CaB6 forms carbides and borides by making partial chemical reaction in a reducing atmosphere, by which the bonding strength of the structure is increased and the gap structure included in the refractories is coarsened. Further, the effects of thermal impact resistance, oxidation resistance, decrease of surface roughening, etc., are obtd. |
