Cao Shun-hua

Densification mechanism of warm compaction and powder mixture designing rules

By phenomenological analysis of warm compaction, it is found that, compared with the contribution of particle plastical deformation to densification of powder compact, the particle rearrangement is a dominant densification mechanism for powder warm compaction, and the plastical deformation of particles plays an important role in offering accommodating deformation for particle rearrangement and densifying powder compact at the final stage of pressing. In order to attain density gain as high as possible during warm compaction, six rules for designing warm-compacting powder mixtures were proposed in detail.

Preparation of Electrical Contact Materials by Cold Gas-Spray

Abstract This work shows the feasibility of cold gas-spray technique for the manufacturing of industrial electrical contact materials. Microstructure and mechanical properties of the material were investigated using optical microscopy, scanning electron microscopy, hardness test and shearing test. Results show that the bonding strength of the material is determined by the hardness of substrates. High hardness results in low bonding strength. Bonding strength of AgSnO 2 sprayed onto aluminum is the best, followed by copper and brass. The bonding strength of silver graphite is not as good as that of silver tin-oxide. The most appropriate particle size is 20 μm for a bulk particle according to the optimization.