To provide an innovative material which combinedly has physical properties, namely, high corrosion resistance and high strength even under ultrasevere corrosive conditions such as a boiled concentrated sulfuric acid solution (e.g. a 75% H2SO4 aqueous solution (at 180°C)), high strength even at high temperatures and high toughness even at low temperatures, the properties not having been combinedly exhibited heretofore, and to provide a method for efficiently producing the same.
In the highly corrosion resistant, high strength, high toughness, nitriding-treated Mo alloy worked material, fine nitrides formed in such a manner that nitride forming metallic elements formed into a solid solution are internally nitrided are dispersed over the inside of the worked material, and an Mo nitride layer formed in such a manner that the worked structure or recovered structure at the surface of the worked material is externally nitrided is formed on the surface thereof. The worked material is produced by subjecting an alloy worked material in which Mo is used as a matrix phase, and at least one kind of metal selected from Ti, Zr, Hf, V, Nb and Ta is allowed to enter into the solid solution to be subjected to the internal nitriding treatment so as to stepwise increase treatment temperature, and next performing external nitriding treatment.
NAGAE MASAHIRO
NAKANISHI MAKOTO
TAKITA TOMOHIRO
UNIV OKAYAMA
ALLIED MATERIAL CORP
Next Patent: INORGANIC FILM DEPOSITION METHOD