Nano-Y2O3 effects on the electrical contact properties of Al2O3-Cu/35Cr3TiB2 composites

Abstract

Al2O3-Cu/35Cr3TiB2 and 0.5Y2O3/Al2O3-Cu/35Cr3TiB2 electrical contact composites were prepared by vacuum hot pressing sintering endo-oxidation method. Both composites were over 98% dense with tensile strengths of 395 MPa and 413 MPa and compressive strengths of 839 MPa and 898 MPa, respectively. The TEM results showed that Cr and TiB2 particles along with Al2O3 nanoparticles generated by internal oxidation were uniformly distributed in the Cu matrix. The addition of Y2O3 had almost no negative effects on the electrical conductivity and hardness of the composites. The electrical contact parameters such as arc energy, arc duration, and weld force between pairs of contacts were analyzed. The material transfer direction of both composite contacts was from cathode to anode. The average welding force of the contacts decreased by 24.6% after the addition of Y2O3, and the material transfer and loss decreased by 28.6% and 42% at 35 A current, respectively. The addition of Y2O3 reduced the arc energy and duration by 43.7% and 55.9% at 25 A and 35 A, respectively, and improved the stability of the contacts during disconnect and closure.