Abstract

Silver coated copper composite powders were prepared by electroless plating method by controlling the activation and deposition process variables such as feeding rate of silver ions solution, concentration of reductant and molar ratio of activation solution (NH_4OH/(NH_4)_2SO_4) at room temperature. The characteristics of the product were verified by using a scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic absorption (A.A.). It is noted that completely cleansing the copper oxide layers and protecting the copper particles surface from hydrolysis were important to obtain high quality Ag-Cu composite powders. The optimum conditions of Ag-Cu composite powder synthesis were NH_4OH/(NH_4)_2SO_4 molar ratio 4, concentration of reductant 15g/l and feeding rate of silver ions solution 2 ml/min.

• Keywords: Ag-Cu composite powders;Electroless plating;Electronic materials;EMI shielding;Surface characteristics;