Research Of Copper-based Friction Meterial By Metal Injection Molding

Metal Injection Molding (MIM) for its products with high quality, high-precision powder metallurgy industry and so become a hot research in recent years. For copper and copper alloy with high heat conductivity, good plasticity, extension rate, small oxygen affinity at room-temperature, high corrosion resistance and a series of advantages, in the modern thermal conductivity, friction materials, such as to occupy an important position.This article was prepared by Metal Injection Molding to produce friction material, optimize the parameters of material preparation process. On the basic of technology, the microstructure,density , friction and wear characteristics of the copper-based powder metallurgy friction material treated by surface transformation were systematically studied and analysised by means of scanning electron microscopy(SEM), X-ray diffraction (XRD),and wear tester and other equipment. Finally, given the comprehensive performance of friction and wear by comparative studies.Based technology test showed that the best injection molding feedstock preparation process: powder loading: 54%, adhesive formulations: 60% PW +25% LDPE +10% SA, mixing temperature: 150℃, mixing time: 2h. The injection pressure, injection temperature, injection speed and their interaction on the quality of preform injection were studied by orthogonal system to evaluate the various parameters on the forming blank quality, access the effection of injection molding process parameters optimization on injection .Optimal injection parameters were: injection temperature 155℃, injecting pressure of 110MPa, the injection speed 40 m?s-1 clamping force of 90MPa, holding time of 10s. The best skim process parameters were 40℃for degreasing 6h. The following sintering at 560℃, the heating rate should be controlled under the 2℃·min-1; rapid cooling can be a way to cool after the heating process. When Sintering, with the increasing of the temperature, the density of the sample gradually increase; extend the high temperature stage's holding time conducive to 10min to eliminate porosity, thereby increasing the density of the sample.Friction and wear tests show that with the graphite content increases the metal powder injection molding preparation friction material increases the porosity, causing the density of the matrix material and hardness decreased. When the graphite content of less than 10%, with the increase of graphite content, reducing friction material and the wear rate of the coupled parts decreased. When the graphite content is 10% to 15%, the wear rate low and the friction coefficient can be stable at low levels, thereby reducing the friction-reducing material consumption to form a protective film reduces wear on the coupled parts, protection of the coupled parts; When the graphite content is more than 15%, the wear rate of friction increase, the friction coefficient increases. When the graphite content from 10% to 15% both anti-friction material to obtain better density, hardness, friction-reducing effect and can give full play to the protection of dual pieces.