초록 ▼

A problem addressed by this invention was how to obtain very long lengths of refractory metal-coated multifilamentary yarns having a uniform coating on the filaments which make up each yarn, the coating being uniform throughout the length of the yarn such that the coated yarns are suitable for being

A problem addressed by this invention was how to obtain very long lengths of refractory metal-coated multifilamentary yarns having a uniform coating on the filaments which make up each yarn, the coating being uniform throughout the length of the yarn such that the coated yarns are suitable for being woven and are suitable for a variety of other uses. The solution is a continuous process which employs a chemical vapor deposition reaction at relatively low temperature and pressure and a separation of the gaseous reaction products from the coated yarn prior to allowing the coated yarn to cool.

대표청구항 ▼

A method of coating long lengths of at least one multifilamentary yarn with a first metal selected from the group consisting of tantalum, niobium, tungsten, molybdenum, and rhenium, said multifilamentary yarn being made up of a bundle of individual filaments and being made of a material selected fro

A method of coating long lengths of at least one multifilamentary yarn with a first metal selected from the group consisting of tantalum, niobium, tungsten, molybdenum, and rhenium, said multifilamentary yarn being made up of a bundle of individual filaments and being made of a material selected from the group consisting of graphite, carbon, ceramics, and metals, so as to produce yarn which is substantially uniformly coated on all filaments throughout each yarn bundle, said method comprising: (a) passing said at least one multifilamentary yarn continuously through a coating chamber into which a mixture of a gaseous halide of said first metal and H2 gas is being continuously introduced and then passed along a line which is substantially parallel to said yarn, said coating chamber being heated to a chosen temperature which is sufficiently high to enable said halide of said first metal and said hydrogen to react to form said first metal, said chosen temperature being lower than about 1100°C. and said coating chamber being operated at a total pressure within the range from about 1 to about 300 torr, (b) allowing said gaseous halide of said first metal and said H2 gas to react at said chosen temperature to form said first metal at the surfaces of said yarn filaments, thus producing at least first metal-coated fibers and an acid halide gas, (c) separating said first metal-coated fibers from said acid halide gas and from all reactants and other gaseous reaction products in said coating chamber by passing an inert gas purge over said first metal-coated fibers so as to minimize contact by back-diffusion of said first metal-coated fibers with said reactants, said acid halide gas and said other gaseous reaction products, and then (d) allowing said first metal-coated fibers to cool.