Investigation of mechanical and corrosion properties of copper matrix hybrid composite materials produced by powder metallurgy method

Pure copper is widely used in various electrical applications due to its high electrical conductivity and high thermal conductivity. Although copper has these excellent properties, the ductility of copper makes it vulnerable to mechanical stress. For this reason, studies on copper alloys and copper matrix composite materials are quite intense. In this study, the microstructure, mechanical and corrosion properties of Cu-Cr-B4C-CNF hybrid composites produced by powder metallurgy were investigated. While microstructural properties were examined by optical, SEM-EDS and XRD analyzes, hardness and wear tests were carried out to determine the mechanical properties. Pin-on-disc wear method was used to determine the wear performance of the composites. Three different wear loads (5N, 10N and 15N) were selected in the wear test. The corrosion properties of the composites were determined using the potentiodynamic method. For potentiodynamics and corrosion rate, Cu-Cr-B4C-CNF hybrid composites were immersed in a 3,5 wt% NaCl solution at pH 6-7. Corrosion current density, corrosion potential and corrosion rate of hybrid composites were calculated from the Tafel curves read directly from the corrosion device. The microstructure results showed that the reinforcement elements were distributed relatively homogeneously in the copper matrix. Cu, CrB2, Cr2B3 and C phases were detected in the microstructure. The hardness of the composite increased with the addition of reinforcement and reached the maximum value (72,5 HB) of 1% of CNF, and after this CNF ratio, a slight decrease in the hardness value occurred. According to the wear results, while the friction coefficients and wear rates decreased depending on the reinforcement ratios, both the friction coefficients and the wear rates increased with the increase of the wear loads. Corrosion test results showed that Cu matrix had the best corrosion resistance. It was determined that when the reinforcement was added, the corrosion resistances decreased partially, but the Cu-8B4C-6Cr-2CNF hybrid composite had the best corrosion resistance among the composites.