Investigation of surface properties of electrical contact material coated with Cu-TiB2 composite by using hot pressed sintering method

In this study, Cu substrate material was coated with Cu-TiB2 powders using hot pressing sintering method. In the applied coating method, the mechanical and microstructural properties of the composite materials forming the coating layer were investigated depending on the effects of reinforcement ratio and sintering temperature. In the coating process, 0%, 5%, 12.5%, 20% and 25% TiB2 powder by volume was added into the Cu matrix powders and mixed with a 3D mechanical mixer. In the mixing process, the mixing speed was determined as 350 rpm, the mixing time was 25 minutes and the ball/powder ratio was determined as 15:1. The powders mixed at different ratios were subjected to sintering process at 900 °C, 950 °C and 1050 °C in a steel mold in an argon gas atmosphere. The samples produced after sintering were compressed unidirectionally under 110 MPa pressure in an argon atmosphere. In order to determine the effects of production parameters on the physical and mechanical properties of the samples, OM and SEM images of the coating layer and cross-section microstructure, XRD and EDS analyzes were taken. In addition, the coating layer was subjected to macrohardness and linear back and forth wear tests. According to the results obtained, when the Cu substrate material was coated with the hot pressing sintering method, it was observed that the Cu and TiB2 powders mixed homogeneously and formed a good bond in the OM and SEM images. It was determined that the macrohardness of the coating surface increased and the wear loss decreased as the TiB2 volume ratio increased in the Cu-TiB2 coating layer. It was determined that with the increase of the sintering temperature used in the coating process, the spaces between the powders in the microstructure of the samples decreased and became smaller, resulting in an increase in macrohardness and a decrease in wear mass loss.