Hiroyasu Mitani1 and Masaru Yokota1
1Department of Metallurgy, Faculty of Engineering, Osaka University, Suita
In a previous paper(1) we have already reported that the addition of nickel powder to the Cu- γ 2(Cu9Al4) mixed powder compact reduced the expansion of the compact during sintering.
By using chemically nickel plated copper or γ 2 composite powders, in the present study we carried out a more detailed examination of the sintering process for mixed powder compacts of the Cu- γ 2-Ni system in order to improve the distribution of nickel in the compacts.
The results obtained were as follows:
(1) The Cu-( γ 2-Ni) mixed powder comact expanded comparatively during sintering. However, the (Cu-Ni)- γ 2 mixed powder compact shrinked remarkably during sintering, where (A-Ni) denotes the chemically nickel plated A-powder.
(2) Homogenization at a given sintering condition proceeds more rapidly in the mixed powder compact of (Cu-Ni)- γ 2 than in the Cu-( γ 2-Ni) mixed powder compact.
(3) The above differences in the dimensional changes and the homogenization process between the (Cu-Ni)- γ 2 and the Cu-( γ 2-Ni) mixed powder compacts were explained on the basis of unequal interdiffusion of each element: if the mass of A-atoms diffused into the B-particles is the (MA)B, (MAl+MNi)Cu (MCu+MNi)γ 2, in the (Cu-Ni)- γ 2 system and (MAl+MNi)Cu<(MCu+MNi)γ 2 in the Cu-( γ 2-Ni) system.
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