Microstructure And Properties Of Ceramic Particles/carbon Fibre Hybrid Reinforced/Cu-graphite Composites

The fundamental principles and basic techniques of copper coating on the surface of TiB₂ ceramic particles as well as electroless plating on the surface of carbon fibre were discussed in this paper. By the adjustment of the traditional composition of solution through degreasing and coarsening the surface of ceramic particles without sensitizing and activation treatment, copper electroless plating can be proceeded directly with lower speed. The influence of temperature, pH value, initial concentration of CH₂O and loading capacity on copper coating were studied. The results indicates that smooth and compact layer can be gained when the temperature is 55～60℃, pH value about 12.5, initial concentration of CH₂O 16 ml/L, loading capacity 4 g/L and time for electroless plating 20～30min.TiB₂-Cf-Cu-graphite matrix composite and copper-coated-TiB₂-Cf-Cu-graphite matrix composite were obtained by powder metallurgy process. The relationship between the content of TiB₂ as well as carbon fibre and density, electrical resistivity, hardness, and bending strength was researched. The investigation showed that with the increase of the content, the density, HV and bending strength of Cu matrix composite were enhanced accordingly, but the electrical resistivity decreased. With the same components, when copper-coated-TiB₂-Cf-Cu-graphite matrix composite was compared to the TiB₂-Cf-Cu-graphite matrix composite, the HV and bending strength of the former was higher than the latter and the former electrical conductivity was superior to the latter.The frictional wear tests were carried out on six kinds of composites. By comparing the mechanical wear extent, the results showed that with the stable content of TiB₂ or carbon fibre, the wear capacity of the samples were distributed in curve and reached its minimum when the content of TiB₂ or carbon fibre was 1%. By comparing copper-coated TiB₂ with TiB₂, the wearing resistance of the former was superior to the latter and for the compound of carbon fibre and TiB₂, it was superior to the single.