| The main feature of dispersion strengthened copper matrix composites is that ceramic phaseparticles with great physical and chemical stability, It not only has good electrical conductivity andmechanical properties at room temperature, and still keeps its superior conductivity andmechanical properties at high temperature, Dispersion strengthened copper matrix composites havepotential applications in electrical contact areas, such as in high speed railway wire, the relay onthe spacecraft, high and low voltage electrical contact. The density of MgO style is3.85g/cm3, theboiling point is3600℃, melting point is2852℃, and MgO has high hardness, high strength, highthermal conductivity, and the lattice type is similar with copper (face-centered cubic lattice), whichis easy to form a good interface structure, MgO/Cu composite material has high comprehensiveperformance.In this paper., the performance testing and microstructure analysis of MgO/Cu compositeswhich prepared by SPS method, internal oxidation method and power metallurgy method werestudied, Focuses on the content of MgO which prepared by SPS method to the influence of theelectric erosion resistance and different preparation methods for MgO/Cu composite electricerosion performance.The results showed that:1. MgO/Cu composite which prepared by SPS method has small grain size, compact structure,with the increase of MgO style volume fraction, the conductivity of the MgO/Cu compositesshows the tendency of decline gradually, and the hardness after the first increase trend lower. Whenthe MgO particle volume fraction reaches5%the performance of the composite is better, theconductivity of the MgO/Cu composite can achieve78%IACS, hardness is110HV. The MgOparticles in the MgO/Cu composites fabricated by internal oxidation had a good interface bondingwith copper matrix, Internal oxidation technology research shows that when the oxidationtemperature is900℃, the time is10h,, the oxide layer thickness of MgO composite achieve1.203mm, electric conductivity is76%IACS, hardness is123HV, its comprehensive performance isbetter.2. MgO content of MgO/Cu composites has the important influence on electrical erosion resistance.①In the process of electric contact, the quality of MgO/Cu composites which preparedby SPS method transfer from static contact to move contacts, with the increase of content of MgOstyle, the quality loss presented to the lower tendency;②when the content of MgO style is1%,arc energy increase sharply with the increase of electric contact number; with the increase ofcontent of MgO, arc energy changed little when MgO content reaches from3%to5%; however,When MgO content reaches8%, with the increase of the contact number, arc energy has a tendencyto increase.③Within the scope of the experiment, when the content of MgO is5%, the total massloss and arc energy is low, the electrical erosion resistance is better.④Microstructure showed thatMgO/Cu composites dynamic contact surface presented liquid metal flow layer state, the staticcontact surface form pit due to the transfer of the material after electric erosion, the microstructureof Porosity, protuberance and crack were found in the contact surface. Pit area with the increase ofcontent of MgO style has a decreasing trend; pit area is minimal when MgO content is5%.3. Experimental conditions, difference of three kind preparation methods of MgO/Cucomposites electrical erosion resistance is big. The quality loss and arc energy of MgO/Cucomposite which prepared by internal oxidation is minimum. With the increase of the number, arcenergy changed little. Microstructure show that after electric erosion molten drop of MgO/Cucomposite which prepared by internal oxidation is smallest, and electrical erosion resistance isbetter. |
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