Multiple phase alloys and metal membranes for hydrogen separation-purification and method for preparing the alloys and the metal membranes

A method for the preparation of an Ni—Ti—Nb based multiple phase alloy for hydrogen separation-purification, consisting of a combined phase which comprises a phase responsible for the hydrogen permeability and a phase responsible for the resistance to hydrogen embrittlement wherein the method comprises the steps of blending desired amounts of Ni, Ti and Nb and then melting a resulting blend according to an arc melting technique carried out in an inert gas atmosphere, a high frequency induction heating technique carried out in an inert gas atmosphere or in a vacuum, an electron beam melting technique carried out in a vacuum, or a laser beam heating technique;

• wherein
• the multiple phase comprises an eutectic mixture (NbTi+NiTi) of an NbTi phase in which Ni is dissolved and which is responsible for hydrogen gas-permeability and an NiTi phase in which Nb is dissolved and which is responsible for resistance to hydrogen embrittlement;
• or a phase comprising the eutectic mixture and the initial phase NbTi.

A method for the preparation of an Ni—Ti—Nb based metal membrane for hydrogen separation-purification, wherein the method comprises the steps of blending desired amounts of Ni, Ti and Nb so that a resulting Ni—Ti—Nb based alloy has a composition satisfying a formula:

• NixTixNb(100-x-y) (wherein x=25˜45 mol % and y=25˜55 mol %);
• melting a resulting blend according to an arc melting technique carried out in an inert gas atmosphere, a high frequency induction heating technique carried out in an inert gas atmosphere or in a vacuum, an electron beam melting technique carried out in a vacuum , or a laser beam heating technique, to form a metal membrane;
• and then forming Pd films or Pd alloy films on both sides of the metal membrane or on a side thereof to which a feed material to be treated is supplied and on an other side thereof from which a purified hydrogen is removed.