Method of coating metal carbide nitride, and carbonitride whiskers with metal carbides, nitrides, carbonitrides, or oxides

摘要

A method for coating single crystal whiskers of carbides, nitrides or carbonitrides of Ti, Zr, Hf, V, Nb, Ta, or W with one or more layers of a carbide, nitride or carbonitride of Ti, Zr, Hf, Nb, Ta, or W, or oxides of Al, Zr, or Hf. The method involves flowing past the whiskers at about 1025 DEG -1125 DEG C. a mixture of hydrogen and one of the following gaseous mixtures: Group I comprises one or more of Ti, Zr, Hf, Nb, Ta, or W hhalides mixed with one or more of N2, NH3, or suitable free carbon forming aliphatic hydrocarbons. The atomic ratio of carbon and/or nitrogen to metal is about 5:1-16:1, and the volume ratio of hydrocarbon and/or N2 and/or NH3 to H2 is about 1:5 to 1:20. Group II comprises one or more Al, Zr, or Hf halides mixed with one or more suitable oxygen donor gases, in proportions selected to form the desired metal oxide.