Getter activation and use
A method for removing a contaminant from an environment is described comprising the steps of: (i) heating a reduced and passivated getter material containing crystallites of a metal in elemental form encapsulated by a layer comprising an oxide of the metal to a temperature in the range (TT−X) to (TT+Y), where TT is the Tammann temperature of the metal in elemental form in degrees Centigrade, X is 400 and Y is 200, to form an activated getter material having active surface for contaminant removal and (ii) exposing the activated getter material to the environment containing the contaminant.
1 . A method for removing a contaminant from an environment comprising the steps of: (i) heating a reduced and passivated getter material containing crystallites of a metal comprising nickel, cobalt, or copper in elemental form encapsulated by a layer comprising an oxide of the metal and dispersed over the surface of a support to a temperature in the range (T T −X) to (T T +Y), where Tris the Tammann temperature of the metal in elemental form in degrees Centigrade, X is 400 and Y is 200, to form an activated getter material having a surface active for contaminant removal and a reduced metal surface area in the range of 5 to 50 m 2 /g and (ii) exposing the activated getter material to the environment containing the contaminant.
2 . The method according to claim 1 , wherein the heating step is performed on the reduced and passivated getter material before, during or after it is transferred to a container in which it is to be used.
3 . The method according to claim 2 , further comprising a step of sealing the container under a vacuum or an inert gas to form a sealed container.
4 . The method according to claim 1 , wherein the metal in the reduced and passivated getter material comprises nickel.
5 . The method according to claim 4 , wherein the nickel content of the reduced and passivated getter material is in the range 1 to 95% by weight.
6 . The method according to claim 1 , wherein the crystallites of the metal in elemental form encapsulated by the layer comprising an oxide of the metal are formed by precipitation of reducible metal compounds and support compounds from solution or impregnation of reducible metal compounds on a support.
7 . The method according to claim 1 , wherein the reduced and passivated getter material has a degree of reduction in the range of 10 to 90%.
8 . The method according to claim 1 , wherein the heating step is performed under a vacuum of at least 98.7%.
9 . The method according to claim 1 , wherein the heating step is performed under an inert gas selected from nitrogen, helium and argon.
10 . The method according to claim 1 , wherein the metal in the reduced and passivated getter material is nickel and the temperature to which the reduced and passivated getter material is heated is in the range 190 to 790° C.
11 . The method according to claim 1 , wherein the contaminant is selected from one or more of hydrogen, carbon dioxide, water, oxygen, carbon monoxide and a hydrocarbon.
12 . The method according to claim 1 , wherein the contaminant is hydrogen.
13 . The method according to claim 4 , wherein the nickel content of the reduced and passivated getter material is in the range 10 to 60% by weight.
14 . The method according to claim 1 , wherein the heating step is performed under nitrogen containing less than 0.010% by volume of oxygen.
15 . The method according to claim 1 , wherein the metal in the reduced and passivated getter material is nickel and the temperature to which the reduced and passivated getter material is heated is in the range 300 to 700° C.
16 . The method according to claim 1 , wherein the metal in the reduced and passivated getter material is nickel and the temperature to which the reduced and passivated getter material is heated is in the range 400 to 600° C.