The Preparation And Properties Of Ti₂AlC₂/Cu Composites

Cu-based composites are widely applied in aerospace, machinery, electricity and so on. Ti3AlC2is one of the new layered ternary ceramics which combines the good properties of ceramic and metal, moreover, it has self-lubrication like graphite and MoS2. Therefore, Ti3AlC2can be the ideal reinforcement phase in copper.This paper studied the electroless plating process of copper coated on Ti3AlC2particles, and the Ti3AlC2/Cu composites in different volume percentage were prepared by hot pressing. Its density, electrical conductivity, hardness, flexural strength, friction and wear properties were measured and the morphology and microstructure of the Ti3AlC2/Cu composites were observed by optical microscope (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD). Then the relationship between the microstructure of composites and mechanical, physical and tribological properties were analyzed and the effect of surface modification of powder on the properties of Ti3AlC2/Cu composites was also discussed.The influence of reducing agent, the concentration of Ti3AlC2particles and the temperature of the plating solution on the uniformity of copper layer were investigated. The optimum parameters of copper plating process as follows:pH is12～13, the capacity of Ti3AlC2is4-5g/L, the concentration of HCHO is10～15ml/L, the temperature of the bath is65℃. Uniform and dense plating copper layer with a thickness of500～900nm could be obtained with optimal parameters.Electroless plating a layer of copper onto Ti3AlC2particles can improve the interfacial wettability between ceramic particles and copper matrix, enhance the interfacial bonding strength, improve the physical and mechanical properties of the composites. The density, electrical conductivity, hardness and flexural strength of coated or uncoated Ti3AlC2/Cu composites in different particle contents shown the same tendency, but at the same contents of particles, the properties of coated composites were better than them of uncoated. The relative density and electrical conductivity of composites decreased with the increase in the content of Ti3AlC2, when the Ti3AIC2content was25Vol.%, the relative density of Cu-coated composite was96.35%, the electrical conductivity of composites was6.203×106Ω-1·m-1， improved by44.16%compared with uncoated composite. The flexural strength of the composite was464Mpa when the Ti3AlC2content was25Vol.%, it was improved by89.39%compared with uncoated composite.The friction coefficient of composite decreased with increasing the load, but the wear rate increased with the increased of the load. The friction coefficient and wear rate of Cu-coated Ti3AlC2composites were lower than that of uncoated Ti3AlC2composites. When the load was120N, the friction coefficient of Cu-coated15Vol.%Ti3AlC2/Cu composite could reach0.15, reduced by33.33%compared with uncoated composite, the wear rate was7.670X10-5mm3/N-m, decreased by21.93%compared with uncoated composite.