In Situ Fabrication and Static Contact Resistance of CdMoO4 Reinforced Cu Matrix Composites

Abstract

Particle-reinforced Cu-based electrical contact materials prepared by traditional powder metallurgical methods suffer the same critical problem, where the agglomeration of the addition phases in the Cu matrix significantly deteriorates the performance of the composites and restricts their application. In this work, CdMoO4/Cu matrix composites were fabricated by an in situ method and followed by a powder metallurgical process. Firstly, CdMoO4/particles formed a nucleus and grew up based on the surfaces of Cu particles, realizing the controllable in situ synthesis of mixed powders with homogeneously dispersed CdMoO4 nanoparticles via a one-step reaction. Secondly, the bulk CdMoO4/Cu composites were fabricated by pressing and sintering and then densified by hot-extrusion and cold rolling processes. The microstructures and properties of the extruded and rolled specimens were characterized, respectively. The results indicated that the rolled CdMoO4/Cu composite exhibited excellent comprehensive properties of electrical conductivity and mechanical properties for electrical contact materials. Moreover, the effects of the contact force on the static contact resistance of the extruded and rolled composites were evaluated in the closed state of the contact materials. It was found that the rolled CdMoO4/Cu contact materials possessed a stable electrical contact characteristic with low and steady contact resistance. This work designed ternary CdMoO4 particles to reinforce Cu-based composites with well-balanced performances by an in situ synthesis method and this strategy can be extended to the design of ternary oxide/metal composites utilized as electrical contact materials.

Synthesis of TiCx/Al Composites via In Situ Reaction between AlxTi Melt and Dissolvable Solid Carbon

“…In the ex situ method, ceramic particles are directly added to the metal matrix from the outside, whereas in the in situ method, ceramic reinforcement phases are generated within the matrix directly through chemical reactions. Generally, the interface between the reinforcement phase and the metal matrix in composites synthesized by in situ methods is cleaner and straighter, and it exhibits a higher bonding strength compared to composites synthesized by ex situ methods [19,20]. In TiC x /Al composites prepared through the in situ method, TiC x forms a strong interface bond with the Al matrix, resulting in stronger mechanical properties and higher hardness than the matrix alloy.…”