Sub-micron Co–Al₂O₃ composite powders prepared by room-temperature ultrasonic-assisted electroless plating

Sub-micron Co–Al₂O₃ composite powders were synthesized by ultrasonic-assisted electroless plating process at room temperature with a one-step activating method pretreatment. The effect of process parameters on plating rate, Co content, and the uniformity of cobalt layer was analyzed by transmission electron microscopy (TEM). The results show that as the initial pH values of plating bath increase, the plating rate increases. The plating rate declines as the load increases when the load of powders is less than 12 g·L⁻¹, but increases when the load is greater than 12 g·L⁻¹. The relative Co content of the Co–Al₂O₃ powder declines with the powder load increasing.