Parameters optimization of electroless deposition of Cu on Cr-coated diamond

Electroless copper plating on diamond particles precoated with 1% Cr was carried out to evaluate the effects of various experimental parameters on coating quality and deposition rate to obtain the optimized reaction parameters. The formulated samples under optimized parameters were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectra and optical microscopy. The best parameters, where uniform and maximum coating thickness was achieved, are etching with 20% NaOH for 30 min, sensitization and activation with SnCl₂ and PdCl ₂ for 5 and 20 min, respectively. The composition of the copper solution bath was 16 g/L CuSO₄·5H₂O, 35 mL/L formaldehyde (HCHO), 23 g/L KNaC₄H₄O₆ at 60 C, pH=13 and stirring at (350±15) r/min under ultrasonication.