The process of electroplating ternary SnCuZn alloy on Fe, Cu or Al part includes the following steps: electroplating Cu, Ni or bright Cu to form a coating of 5-50 micron thickness; chemically plating Ni-P or Ni on the said coating optionally to form a coating of 3-30 micron thickness; electroplating ternary SnCuZn alloy layer; roasting the plated part at 110-150 deg.c for 0.5-3 hr to form a coating of 3-30 micron thickness. The present invention is superior to available technology, and the plated part can pass through the environmental test including salt fog test of 48 hr, moisture and heat alternating test of 120 hr and mold test of 392 hr. |