Study On The Structure And Properties Of AgCuOIn₂O₃ Electrical Contact Materials

Silver metal oxide electrical contact materials have become the most widely used materials in the field of electrical contact due to their excellent electrical and thermal conductivity,low contact resistance,high hardness and strength,good resistance to welding and arc erosion.One has an irreplaceable status.Because Cd has environmental pollution problems,it is an inevitable trend that traditional AgCdO universal contact materials are replaced by new environmentally friendly contact materials.Copper oxide（CuO）is a new environmentally-friendly phase in the contact material.It has high thermal stability and good interfacial wettability with the silver matrix.Its properties can increase the liquid metal in the molten pool of the contact surface during electrical contact.The surface tension and viscosity limit the formation of the molten pool on the contact surface and enhance the arc erosion resistance of the contact material.In addition,copper oxide（CuO）has the characteristics of abundant raw materials and low price,which further promotes the research and application of AgCuO electrical contact materials,but the single CuO reinforcing phase still cannot improve the comprehensive performance of electrical contact materials.The results show that the AgCuO electrical contact material with the CuO content of 10%has the best performance.It is also shown that the addition of indium（In）to the AgSnO₂ electrical contact material can qualitatively improve the electrical contact properties of the AgSnO₂electrical contact material.Therefore,in this thesis,AgCuO（10）In₂O₃（x）（x=1,2,3,3.5）electrical contact materials were prepared by reactive synthesis method,and the thermodynamic theoretical calculation and analysis were carried out on the reaction process.Physical properties,electrical contact properties,etc.are tested to combine the advantages of both CuO and In₂O₃ to explore the quantitative relationship between the content of In₂O₃ and the electrical contact properties of AgCuO（10）electrical contact materials,and to obtain mature and feasible processing routing.In terms of theoretical calculation,by calculating the thermodynamics and oxygen partial pressure of AgCuO（10）In₂O₃（x）（x=1,2,3,3.5）contact materials,it is found that the pure metal Cu and In are in the oxidation process.The free energy is less than zero,which indicates that the oxidation process of Cu and In can be spontaneously carried out.The calculation of oxygen partial pressure shows that the partial pressure of oxygen in the reaction process of Cu and In is lower than the partial pressure of oxygen in atmospheric pressure,indicating that the reaction process There is no decomposition reaction of oxides.The microhardness,tensile strength and elongation after break of the contact material were tested.The test results show that with the increase of In₂O₃ content,the post-elongation elongation of AgCuO（10）In₂O₃（x）（x=1,2,3,3.5）electrical contact materials is gradually reduced,and the microhardness and tensile strength are both improved.Increased and tensile strength is significantly higher than AgCuO（10）electrical contact material.The test results of the resistivity of the cold drawn sample show that the electrical resistivity of the electrical contact material gradually increases with the increase of the In₂O₃ content,which is caused by the poor conductivity of the metal oxide.The solder resistance,contact resistance and material transfer characteristics of the electrical contact material were tested.The test results show that the content of In₂O₃ can improve the electrical contact properties of AgCuO electrical contact materials,but the better the content,the better the electrical contact performance of AgCuOIn₂O₃ contact materials when the content of In₂O₃ is 2%.The study of contact resistance shows that the contact resistance of AgCuO（10）In₂O₃electrical contact material is higher than that of AgCuO electrical contact material due to the increase of oxide content,but its anti-welding performance is better than AgCuO（10）.The anti-welding performance of the electrical contact material.When the test voltage is raised from12V to 18V,the anti-welding properties of AgCuO（10）In₂O₃ and AgCuO electrical contact materials are worse,indicating that both are more suitable for low-voltage electrical contact;when the voltage is 18V,AgCuO（10）The anti-welding performance of In₂O₃（x）（x=1,2,3,3.5）electrical contact materials is more stable than that of AgCuO（10）electrical contact materials.Research on material transfer characteristics shows that when the voltages are 12V and 18V,the material transfer direction between the moving and static contacts is transferred from the static contact to the moving contact;In addition,the material transfer is mainly carried out by means of fusion bridge.The loss of material decreases with the increase of In₂O₃ content,and the erosion morphology of the surface of the cathode/anode contact is convex and concave.The arc erosion morphology of AgCuOIn₂O₃ electrical contact material was scanned and compared with the arc erosion morphology of AgCuO（10）electrical contact material.The results show that the addition of In₂O₃ makes the total mass loss of AgCuOIn₂O₃ electrical contact material larger than that of AgCuO（10）electrical contact material.This is due to the fact that the surface of the AgCuOIn₂O₃ contact material forms a large molten pool during the electrical contact,and the larger molten pool can reduce the welding force between the contacts during the electrical contact.