GB491722A - Improvements in the manufacture of sintered hard articles containing metallic carbides - Google Patents

Abstract

Sintered hard articles which contain metallic carbides are prepared by mixing a number of different high melting metals and/or inorganic compounds of different high melting metals with carbonaceous reagents (e.g. coal) in sufficient quantity to form the carbides, subjecting them in common to carbonization which simultaneously in a sintering operation converts them into the sintered hard material, and, before or during this treatment, which may occur in stages with disintegration of the intermediate product and renewed admixture, giving the mixture the form of the desired hard article which is thereby obtained directly in the solid condition as a useful workpiece. According to an example, tungsten or chromium is admixed with titanic and vanadic oxides and sufficient coal for carburization, the mixture being made by first mixing the proper proportion of coal with the individual metal or oxide and finally mixing the three mixtures together. The final mixture is heated to somewhat above 1500 DEG C. The mixture is moulded into the form of a plate with the employment of a not excessive pressure before carburization. The Specification as open to inspection under Sect. 91 comprises also the production of borides and silicides, and is not confined to sintering processes or to the production of the shaped articles before the completion of conversion. This subject-matter does not appear in the Specification as accepted.ALSO:Sintered hard articles which contain metallic carbides are prepared by mixing a number of different high-melting metals or their inorganic compounds or both with carbonaceous reagents (e.g. coal) in sufficient quantity to form the carbides, subjecting them in common to carburization which simultaneously in a sintering operation converts them into the sintered hard material, and, before or during this treatment, which may occur in stages with disintegration of the intermediate product and renewed admixture, giving the mixture the form of the desired hard article, which is thereby obtained directly in the solid condition as a useful work piece. According to an example, tungsten or chromium is admixed with titanic and vanadic acid and sufficient coal for carburization, the mixture being made by first mixing the proper proportion of coal with the individual metal or oxide and finally mixing the three mixtures together. The final mixture is heated to somewhat above 1500 DEG C. The mixture is moulded into the form of a plate with the employment of a not excessive pressure before carburization. The Specification as open to inspection under Sect. 91 comprises also the production of borides and silicides, and is not confined to sintering processes or to the production of the shaped articles before the completion of conversion. This subject-matter does not appear in the Specification as accepted.