SILVER COATING ON CARBON AND SIC FIBERS

Electroless silver coating on carbon fibres using silver nitrate solutions has been studied. It was observed that the rate of silver coating depends on the degree of graphitization of carbon fibres. Fibres with a higher degree of graphitization were coated.faster than those with a lower degree of graphitization' A physical model considering the number of nucleation sites on the carbon fibre surface as a function of the degree of graphitization is proposed for the silver coating process. The strength and modulus of coated and uncoated fibres have been determined using a high-sensitivity load cell with an Instron tensile testing machine. It was observed that silver coating did not alter the strength or modulus of the fibre. Aluminium matrix composites have been successfully fabricated with these fibres. The same coating technique was also used to coat silicon carbide fibres. Improvement in the infiltration during composite fabrication was observed when the fibres were silver-coated.