Production of high conductive copper alloys and investigation of electric contact performance

Copper is the best conductor after silver in terms of electrical conductivity. However, copper cannot maintain its properties such as conductivity and strength at high temperatures. Even if its strength is increased by cold shaping, it softens immediately at high temperatures. This problem is tried to be solved by making copper alloy or composite. For this purpose, many copper and its alloys developed for electrical contacts are widely used. Within the scope of this study, copper, nickel and SiC (Silicon carbide) powders and particles were mixed in different proportions and the resulting mixtures were shaped by compression under 850 MPa pressure and finally sintered while embedded in graphite for 2 hours at 950 C. After the sintering process, measurements such as metallographic examination, electrical conductivity, hardness and density were made on the samples. In the second stage of the study, hot pressing (SP) was also applied to some TM contact samples at the sintering temperature and the electrical conductivity, density and hardness changes of the samples were re-examined. The results obtained before and after hot pressing were compared. In density measurements, it was observed that the density of the produced contact samples decreased as nickel and silicon carbide were added to copper. Hardness measurements were carried out with a Rockwell (HRA) device. It has been observed that the hardness increases significantly when silicon carbide is added to copper and copper-nickel alloy. In addition, as the SiC particle ratio increased in TM samples produced from copper and copper nickel alloys, a significant decrease in electrical conductivity occurred. It was observed that there was a slight increase in the density, hardness and conductivity values of hot-pressed TM samples at the sintering temperature. Among the TM contact composite samples produced within the scope of this study, the highest hardness value (HRA93) was measured in the hot-pressed (SP) Cu+4%Ni+5%SiC composite, and the highest conductivity value (76% IACS) was measured in the hot-pressed (SP) Cu+1%SiC composite. However, hot-pressed Cu+2Ni+2.5SiC composite, which has both a reasonable electrical conductivity (70%) and a good hardness measurement value (HRA72.3), can be considered a more suitable contact material.