Study of the Properties of a Carbon-Graphite–Based Composite Impregnated with Aluminum Alloys After Preliminary Electroplating of Open Pores with Copper or Nickel

Abstract

The physicomechanical properties of a skeleton composite based on carbon-graphite AG-1500 impregnated with aluminum alloys were investigated after preliminary electroplating of copper or nickel onto the surfaces of the open pores. To improve impregnation of the carbon-graphite by an autoclave-free technique, coatings that form the eutectic with aluminum were used. Investigation of the effect of impregnation temperature showed that increasing the impregnation temperature with AK12 alloy to 750°C led to filling of 43.57% of the open pores of the carbon-graphite pre-plated with copper, while for nickel-plated samples this value was 37.32%. With a further increase of the temperature to 800°C, pore filling increased to 72.27% for the copper-preplated samples and to 66.25% for the nickel-plated samples. Using an Al–Mg–Zn–Cu alloy at an impregnation temperature of 750°C, pore filling of the pre-coppered samples reached 56.87%, and of the pre-nickel-plated carbon-graphite samples 49.25%. It was found experimentally that the copper coating is more effective at improving infiltration of the matrix aluminum alloys than the nickel coating. Analysis of the chemical composition of carbon-graphite impregnated with the Al–Mg–Zn–Cu alloy revealed chemical inhomogeneity of the metal alloy composition in the pores, manifested as segregation of the more active elements (magnesium, zinc) of the matrix alloy toward the interfacial zone with the carbon-graphite. It was established that with increasing degree of pore filling by the matrix alloy, the physicomechanical properties increase (compressive and flexural strength, wear resistance, and specific electrical resistivity of the composite).