Electric discharge sintering of binary powder mixtures

Abstract

1. Experiments on Cu-Ni composite specimens have provided evidence in support of the hypothesis [7] that electric discharge sintering can induce very rapid alloy formation in powder mixtures (for example, the degree of homogenization attained in a 50% Cu-50% Ni mixture subjected to orthodox isothermal sintering for 4 h at 1050°C requires only 45 sec in the EDS process). 2. The key factors in the attainment of a given degree of homogenization in EDS are the integral power consumption and the rate of supply of electrical energy to the powder being sintered. 3. It is shown that in the case of a Ni-Mo composite electric discharge sintering, like ordinary isothermal sintering, is accompanied by dissolution of the molybdenum in the nickel. 4. The formation of an alloy with a high degree of homogeneity from a mixture of Ni and Mo powders in the EDS process occurs very rapidly (in 1.5–1.75 min), whereas in conventional sintering the same degree of alloy formation is reached only after 2 h at 1500° C.