Electroless silver coating on fine copper powder and its effects on oxidation resistance

Electroless silver coating on fine copper powder (3.4 mum) and its effects on oxidation resistance were investigated by varying the silver contents. As-coated copper powders were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the uniformity of silver coating was improved with silver content. When the silver content reached 20 wt.%, silver was homogeneously distributed around the copper particles and few free silver particles were detected. As a result, the sheet resistances of metal films reduced with the silver content (presenting the improvement of oxidation resistance), and at the level of 20 wt.% silver content, it had a minimum value and hardly increased with the increasing oxidation time. (C) 2003 Elsevier Science B.V. All rights reserved.