| 摘要 |
1492599 Catalysts prepared by powder metallurgy INCO EUROPE Ltd 12 Nov 1974 [12 Nov 1973 (2)] 48888/74 Headings C7A, C7D and C7U A catalyst, for use in removal of nitrogen oxides, hydrocarbons and/or CO, from gas mixtures, is an alloy consisting of Cr 5-50, Ni 5-60, Fe 0-15, up to 5% each and up to 10% total of one or more of La, Ce, Y, Ba, Ag, Pt, Li, Pb, V, Sn, Si or compounds (e.g. oxides) thereof, 0-20% in total and 0-10% each of Co, Mn and Mo the balance being Cu, the Cu and Cr contents falling within the area ABCDEA of Fig. 1 of the drawings (not shown) or an alloy comprising 15-45% Cr balance Cu; the alloy having an oxidized stratified surface consisting of a catalytically active outer region separated from the bulk alloy by a thin substantially continuous Crrich intermediate layer. The catalyst may be prepared by powder metallurgy many Examples being given of techniques involving mechanical alloying, extrusion in a sealed can, isostatic compaction and liquid phase sintering, and specifically at least the Cu and Cr constituents may be prealloyed, applied to a heat resistant support with the aid of a fugitive binder and heated to cause liquid phase sintering in a non-oxidizing atmosphere. The catalytic surface may be prepared by heating in an oxygenating atmosphere (e.g. air) at 816- 927‹C for 2-30 hours.
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