銅試片無電鍍鎳後，經800°C'4小時，氧氣保護氣氛熱處理，在鍍層與底材界面會有銅鎳 合金擴散居，擴閥冒厚度與無電鍍鎳鍍層憐含量有關，磷會抑制擴散層生成，所以磷含量較高之無電鍍鎳j晉，在熱l處理時，鎳銅合令擴散層的厚度較小。無電鍍鎳層磷含量大於7wt%時， 其非晶質狀態，熱處理後會有Ni及Ni·1P結晶相析出，在3.5wt%中'I生NaCl溶液中之抗蝕性較 差;銅鎳合金擴閥冒生成且厚度較厚時，腐蝕電位往較鈍態、方向移動，有助於鍍層m蝕性的提高。熱處理後複合鍍層整體耐蝕d性，而見J結晶化無電鍍鎳j晉1J'i�銅鎳合合擴散j商互補情形而定。

Copper nickel diffusion layer could be formed as electrolessly nickel-plated copper was heattreated at 800 for 4 hours under Ar atmosphere. The thickness of CuNi diffusion layer is dependent on the phosphorus content of the electroless nickel coating. The presence of phosphorus inhibits the formation of CuNi diffusion layer during heat treatment. The higher phosphorus content of electroless nickel coating results thinner diffusion layer of CuNi alloy. As P% exceeds 7wt%, the as-plated electroless nickel coating is amorphous. The precipitation of Ni and Ni3P
during heat treatment were observed and adversely to the corrosion resistance in 3.5wt% NaCl aqueous solution . However, formation of CuNi diffusion layer at the interface of coating and substrate shifts the corrosion potential towards more noble direction. The overall corrosionresistant properties of heat-treated electrolessly nickel-plated copper depend on the compensation effect of crystalline electroless nickel layer and CuNi diffusion layer.