The Microstructures and Properties of Novel-Type Cu/Cr2Nb Contact Materials Fabricated Mechanically Activated Hot-Pressing

Abstract:

Using Cu, Cr, Nb elemental powders activated by mechanical alloying (MA) for 25 h, the novel-type Cu/Cr2Nb contact materials were fabricated by vacuum hot-pressing at 1000 ℃ for 1 h. The microstructures and the properties of Cu/Cr2Nb contact materials with different compositions were investigated. The results show that Cr2Nb phase can not be synthesized during MA, but can be fully synthesized during vacuum hot-pressing. The prepared Cu/Cr2Nb contact materials have homogeneous and fine microstructures, and Cr2Nb phase sizes fall in several micro. The relative density of Cu/Cr2Nb contact materials with 25%~35% Cr2Nb is comparable with those of CuCr50 prepared by conventional or infiltrating process, but the hardness and conductivity of the former are obviously superior to those of the latter

Key words:Cu/Cr2Nb contact materials; mechanical alloying; vacuum hot-pressing; microstructures and properties