Influence of Plasma Treatment on the Electroless Deposition of Copper on Carbon Fibers

Air and nitrogen glow discharge were used to replace chromic acid pretreatment to deposit copper film on carbon fiber surfaces from an CuSO₄‐HCHO electroless system. A greater copper uptake and a more uniformly coated copper film were obtained for plasma‐treated carbon fibers. The adhesion between the copper film and the carbon fibers was also improved. An orthogonal table L₉(3⁴) was used to study the effects of discharge pressure, discharge power, time and gas type on the copper uptake. Scanning electron microscopy (SEM), reflection absorption infrared spectroscopy (RAIR) and X‐ray photoelectron spectroscopy (XPS) at different depths were applied to characterize the physical and chemical changes of the surface of the carbon fibers. The results showed that after plasma treatment, the carbon fiber surface became rough and several types of polar oxygen groups, such as carboxylic acid COOH, esters COOC, quinones Ph?O, etc., were introduced into the carbon fiber surface. A mechanism of plasma treatment effects on copper electroless deposition on the carbon fiber surface is also suggested.