Effect of Ni-Fe and Ni-Cr Alloys Addition on Sintering of Molybdenum Powders
A small addition of pure nickel powders not only lowers the sintering temperature of Mo but also remarkably increases its sintered density. For example, a 2wt.% addition produces a 94% achieved density even at one-half of the homologous temperature for Mo, the achieved density strongly depending on the sintering temperature. The sintering proceeds quickly with a lower activation energy compared to the Mo bulk diffusion energy, and the entire sintering is accomplished in a rather short period of time.<BR>On the other hand, when Ni-Fe and Ni-Cr alloys powders are respectively added to Mo, each achieved density is greatly increased at a much higher rate too. For example, a 5wt.% (Ni-20 wt.% Fe) powder addition produces 98.5% at 1673K. The sintering temperature on Ni-Fe and Ni-Cr alloys additions is further increased compared to the case of Ni addition. However, the activation energy (129 kJ/mol) for densification on Ni-Fe alloy addition is less and it (206 kJ/mol) on Ni-Cr alloy addition is more than that (143 kJ/mol) obtained by adding Ni.
粉体および粉末冶金 44(7), 689-693, 1997-07-15
Japan Society of Powder and Powder Metallurgy