SILICON NITRIDE ARTICLE

专利名称：SILICON NITRIDE ARTICLE发明人：ADLERBORN, J.,LARKER, H.申请号：AU2157477申请日：19760124公开号：AU507155B2公开日：19800207

摘要：Method of manufacturing an object of silicon nitride by isostatic pressing of apreformed body of silicon nitride powder with a pressure medium at a temperaturerequired for sintering the silicon nitride, the preformed body then being subjected to adegassing before the isostatic pressing, characterized in that on the preformed powderbody there are applied an inner porous layer of a first material and outside this an outerporous layer of a second material, the inner porous layer, possibly in cooperation withthe second material, being transformable into a layer, impermeable for the pressuremedium, at a temperature below the sintering temperature for the silicon nitride and theouter porous layer being transformable into a layer, impermeable for the pressuremedium, at a temperature which is lower than that for the inner porous layer, whereafterthe preformed body is first subjected to a degassing and to a heating to a temperaturewhich is required for the formation of a layer, impermeable for the pressure medium ofthe outer porous layer but which maintains the inner porous layer porous, and then to aheating to a temperature which is required for the formation of a layer, impermeable forthe pressure medium, of the inner porous layer while maintaining a pressure outside saidlayers which is greater than the gas pressure inside these layers, the isostatic pressing ofthe preformed product then being carried out.

申请人：ASEA AKTIEBOLAG

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