Study On Preparation And Properties Of Novel Ti₃SiC₂-Cu Vacuum Contact Materials

The level of dependency and demand grows day by day along with the humanity on the electric power. The vacuum switches control the electrical power system in safe operation, which gradually becomes the important key equipment in the electric power profession. The contact material as the vacuum switch's core, its properties immediately influence work reliability, stability of conduction system. At present in the vacuum contact device, the commonly used WC-Ag contact material price is expensive, the electricity wearing capacity is big; But WC-Cu or W-Cu contact material cut-off level, electricity life characteristics are obvious low, therefore the development for higher qualified new vacuum contact material has the very vital practical significance.The ternary compound Ti₃SiC₂ has been lay more emphasize as new compound materials. Compared with WC which is commonly used as the enhancement part of the electrical contact materials, Ti₃SiC₂ has similar electrical resistance, better thermal conductibility and higher melting point. Its elasticity modulus and coefficient of thermal expansion are more adjacent to metal, and it has lower specific gravity, its self-lubrication and anti-oxidation properties are better. To mix it with copper instead of WC, it can diminish density of contact materials, reducing material costs, while improving the electrical contact materials performance, saving valuable strategic resources tungsten. Because of these advantages, it is hopeful to be utilized as new electrical contact materials with high properties.In order to improve Ti₃SiC₂/ Cu contact surface union condition, this article first applied electroless copper-plating technique to process pure Ti₃SiC₂ powder body, then with the earlier preparation technical study's foundation, we set the composites agglutination soaking time further optimized, and did comparison of different composites performance between the electroless copper plated Ti₃SiC₂/ Cu and pure Ti₃SiC₂/ Cu.Study results indicated that both the Ti₃SiC₂/ Cu contact material owned very high electric conductivity and extremely high flexural strength intensity; after electroless copper-plating, composites density improved, but the conductivity improvement effect was not ideal. The analysis indicated that factors which affect the Ti₃SiC₂/ Cu composites electric conductivity the factor mainly have two: namely the density and the interface reaction degree. To enhance the compactness, to reduce the interface reaction degree will be helpful to improve the composites electric conductivity. To maintain the other technological parameter under the same condition, to extend soaking time may enhance the Ti₃SiC₂/ Cu composites density and electric conductivity.In this article tests scope, to apply 40vol% pure Ti₃SiC₂ and 60vol%Cu in the agglutination temperature 1000℃, pressure 39MPa with soaking time 120min vacuum condition, we prepared the Ti₃SiC₂/Cu contact material whose electronic resistivity reaches0.047μΩ·m,its flexural strength achieves 1256.83MPa,the entire performance has surpassed the present actual applied WC-Cu contact material.To further examine the practical performance of Ti₃SiC₂/Cu contact material, we made the manufactured contact material processed into (?)32×5mm vacuum contact devices, which smoothly went through the copper brazing experiment. Then we produced three vacuum interrupter chambers, and tested their vacuum degree and the short-time line frequency withstand voltage. Results indicated that their performances were higher than the same type product quality requirments.