Sintering of Cr-60Ni-W and Cr-70Ni-Al alloys bimodal powders prepared by electric explosion of wires

Bimodal powders of chromium-nickel heat resistant alloys containing both micro—and nano-sized particles have been prepared by the electric explosion of wires and characterized by TEM, SEM and XRD methods. The size distribution curve has been found to shift to a smaller particles size as the energy introduced into wire increases. The densification of the alloys samples when sintering has been established to start at temperature above 600 °C. The alloys samples sintered at 1300 °C showed density 0.89 of theoretical for Cr-70Ni-Al alloy and 0.95 for Cr-60Ni-W alloy while encapsulated samples showed density 0.94 and 0.98 respectively. The use of acetylacetone as an encapsulator leads to the formation of a barrier layer on the particles surface which prevents the oxidation and agglomeration of the particles. Microhardness of alloys samples sintered is 2.04 GPa for Cr-70Ni-Al alloy and 2.89 GPa for Cr-60Ni-W alloy. (paper)