The Research On Wear And Corrosion Behavior Of Copper Alloy

Copper alloys have a series of good comprehensive performances:high electrical conductivity, good corrosion resistance, high elastic modulus, high strength and marine pollution resistance. Some also have good cutting performance or wear resistance. Therefore, copper alloys are widely used in many industries such as ship parts, valve stem, submarine pipeline, railway contact wires and metal lead frame. In this paper, the corrosion resistance of the Cu-Zn alloy and wear resistance of copper alloy using on contact wire were studied.It is generally known that the Cu-Zn alloy containing about 27-30 wt.%Zn is widely used in many countries of the world, due to its good corrosion resistance and high strength. In general, produced Cu-Zn alloys with Zn in the 27-30 wt.% range are considered to be eligible in industry. In fact, the variety of Zn in this range may have an obvious influence on the corrosion performance of Cu-Zn alloy. At present, most researchers focus on adding or reducing some trace alloy elements such as Al, Fe, B and RE, so as to enhance the corrosion resistance of Cu-Zn alloy. Up to now, there are few reports about the influence of tiny differences on Zn component of Cu-Zn alloy on the corrosion behavior of copper in the range of a specified alloy. Therefore, this paper aims to investigate the corrosion resistance of a series of tin Cu-Zn alloys with small different Zn contents in chloride solution by the salt spray exposure measurement and electrochemical methods. The purpose is to study the optimum Zn composition or corrosion resistance versus tiny Zn content change in the Cu-Zn alloy with 27-30 wt.%Zn. In the present study, a series of Cu-Zn alloys (CuZnSnAlNiAsBRE) with different Zn contents were designed and their corrosion behavior in salt spray environment was investigated. The corrosion behavior was characterized using mass loss, electrochemical impedance spectroscopy (EIS), polarization curves, and surface morphology observation, with exposures lasting up to 360 h. With the increasing exposure time, the mass loss increases but the corrosion rate decreases. Corrosion rates of the alloys containing 28.3-28.8 wt.%Zn are lower than those of the other alloys. The corrosion products are a mixture of ZnO, SnO2, CuCl, CuCl2, CuO, Cu2O and Cu(OH)2. The present study clearly demonstrates that tiny different Zn contents have an obvious influence on corrosion resistance The investigated Cu-Zn alloys containing 28.3-28.8 wt.%Zn are found to have a better corrosion resistance in salt spray environment.Copper alloy should possess high mechanical property and excellent wear performance at the same time of maintaining high electrical conductivity and thermal conductivity. This paper also focuses on the dry sliding friction and wear performance of Cu-Sn, Cu-Ag and Cu-Mg alloy using on contact wire prepared by continuous extrusion. The experiment equipment is a MMS-2 screen-displayed friction and wear testing machine. This experiment has tested and analyzed friction coefficient, wear rate, the friction and wear surface morphology and its friction and wear mechanism of copper alloy with different composition. The effect of normal load and sliding velocity on friction and wear performance was investigated. The morphology and composition of the worn surface of specimens were analyzed by SEM, and the corresponding mechanism was discussed. Wear rates and friction coefficients were measured in a sliding velocity range of 0.1-0.3 m s-1 and normal load range of 50-110 N. The main conclusions are as follows:(1) The friction and wear performance of Cu-Ag alloy is much better, the friction and wear performance of Cu-Mg alloy is much worse. (2) The friction and wear property of copper alloy is different under different load and sliding velocity. The greater the load is, the higher the wear rate is. Under the condition of low sliding velocity, the greater the sliding velocity is, the higher the wear rate is. The varying friction coefficients remarkably influenced by the formation of a continuous tribofilm which consists of oxidation film. Varying of wear rate under different normal loads and sliding velocities is correlated to the wear mechanism. (3) The main wear mechanism of copper alloy is abrasive wear, adhesive wear, oxidation wear and plastic deformation. Oxidation and abrasion mechanisms dominate at the lower sliding velocities and loads. Increasing loads and velocities leads to a combination of oxidation and adhesion. Plastic deformation is detected for the higher applied load and sliding velocities.