Hydrogen-permeable alloy, and hydrogen-permeable film and its production method

Abstract

A hydrogen-permeable Nb—Ti—Ni alloy having a composition represented by Nb 100-x-y Ti x Ni y , wherein 10≦x≦60, and 10≦y≦50 by atomic %, with an oxygen content of 1000 ppm or less in an as-cast state, which comprises (a) a hydrogen-permeable primary phase containing 70 atomic % or more of Nb and 10 atomic % or less of Ni, and (b) a eutectic phase having a particle phase comprising Nb and Ti as main components with a small Ni content and having an average particle size of about 5 μm or less, which is dispersed in a matrix phase comprising 60 atomic % or more in total of Ni and Ti and having hydrogen embrittlement resistance, the alloy having a structure substantially free from an intermetallic compound phase.

1 . A hydrogen-permeable Nb—Ti—Ni alloy comprising a hydrogen-permeable phase and a hydrogen-embrittlement-resistant phase, which has an oxygen content (measured in an as-cast state) of 1000 ppm or less. 
     
     
         2 . The hydrogen-permeable alloy according to  claim 1 , which has a primary phase having an oxygen content (measured by EPMA) of 2000 cps or less. 
     
     
         3 . The hydrogen-permeable alloy according to  claim 1 , which has Vickers hardness of 270 HV or less. 
     
     
         4 . A hydrogen-permeable film produced by heat-treating and rolling the hydrogen-permeable alloy recited in  claim 1 . 
     
     
         5 . A hydrogen-permeable Nb—Ti—Ni alloy having a composition represented by Nb 100-x-y Ti x Ni y , wherein 10≦x≦60, and 10≦y≦50 by atomic %, with an oxygen content of 1000 ppm or less in an as-cast state, which comprises (a) a hydrogen-permeable primary phase containing 70 atomic % or more of Nb and 10 atomic % or less of Ni, and (b) a eutectic phase having a particle phase comprising Nb and Ti as main components with a small Ni content and having an average particle size of about 5 μm or less, which is dispersed in a matrix phase comprising 60 atomic % or more in total of Ni and Ti and having hydrogen embrittlement resistance, said alloy having a structure substantially free from an intermetallic compound phase. 
     
     
         6 . A method for producing a hydrogen-permeable film having a thickness of 0.01-1 mm, comprising heat-treating and rolling a cast alloy body having a composition represented by Nb 100-x-y Ti x Ni y , wherein 10≦x≦60, and 10≦y≦50 by atomic %, and an oxygen content of 1000 ppm or less. 
     
     
         7 . A method for producing a hydrogen-permeable film having a composition represented by Nb 100-x-y Ti x Ni y , wherein 10≦x≦60, and 10≦y≦50 by atomic %, and a thickness of 0.01-1 mm, comprising the steps of (1) mixing alloy materials comprising Nb metal, Ti metal and Ni metal each having an oxygen content of 1000 ppm or less, with 30-1000 ppm of a deoxidizer based on the entire weight of said alloy materials, (2) melting said alloy materials in an atmosphere obtained by evacuating to 6×10 −3  Pa or less and then introducing an inert gas, to produce a cast alloy body having an oxygen content of 1000 ppm or less, and (3) repeatedly annealing and rolling said cast alloy body to a thickness of 0.01-1 mm.