Fabrication And Properties Of A ZnO Reinforced Cu-Matrix Composite

Current researches on the reinforcements used in particulate-reinforced composites mainly focus on two categories, hard alloys and cermets. The former includes particulates of steel and tungsten etc, while the latter incudes Al2O3, SiC, TiN, AlN, TiB2, ZrO2 and WC etc. Among them, ZnO is a kind ofâ…¡-â…¥compound semiconductor with a broadband gap. It possesses excellent optical and electrical properties in addition to its low cost and innocuity. ZnO reinforced silver-matrix composites have been reported by previous researchers. While studies on the ZnO reinforced Cu-matrix composites have not been found at literatures as yet. The present study took a preliminary exploration on the fabrication and properties of a ZnO / Cu composite with the aim to find a novel Cu-matrix composite with a combination of high electrical conductivity and high strength.In the present study, a powder metallurgy technique is used to fabricate the composite with various mass fraction of ZnO. Four factors and three levels orthogonal experiment is adopted in the optimization of fabrication technics. The microstructures, phase structures as well as the physical and mechanical properties of the resultant composite have been investigated, including the researches on density, hardness, electrical conductivity, and the properties of compression, bending, wear and corrosion. It is found as follows:1. X-ray diffraction analysis indicates that there is no other phases in the resultant composite in addition to Cu and ZnO.2. Observation of SEM and micro-area chemical analysis show a distict interface between Cu and ZnO. There exists diffusion between the two phases, and the diffusivity of Cu is greater than that of ZnO.3. Compared with the pure Cu fabricated by using the same method, the hardness of the composite has been marked elevated, while decrease of the electrical conductivity is indistinguishable. With increasing the mass fraction of ZnO, the density and electrical conductivity of the composites decrease, while the hardness shows a nonmonotonous change, i.e. hardness firtly increases until reaches a maximum then decreases monotonously. The composite with a 10% mass fraction of ZnO possesses the best general properties, density is higher than 98%, and the hardness and electrical conductivity are HV98 and 41.5MS/m, respectively.4. The wear resistance of the composite is superior to that of the pure Cu fabricated by using the same method. When the content of ZnO is relatively low, an adhesive wear plays a dominant role. With increasing the content of ZnO, the wear mechanism changes into the combination of adhesive wear and fatigue wear. On continued increasing the content of ZnO, an abrasive wear will also appear.