触点镀金材料的自然腐蚀和电接触特性研究

Natural corrosion and electrical contact property of gold plating on contacts.

由于国内环境污染严重，镀金表面经过长期室内自然暴露后生成了大量呈岛状离散分布的腐蚀物。腐蚀物由处于中心的腐蚀核及环绕的腐蚀晕圈组成，腐蚀核下是微孔。在镀金表面的腐蚀物上进行微动试验，发现较薄的腐蚀晕圈同样会造成高且波动的接触电阻，随微动周期增加，腐蚀物被推开后电阻降低。加大接触正压力，初始接触电阻降低，波动减弱，较少微动周期后电阻降为正常值。由于腐蚀晕圈远大于腐蚀核在表面覆盖的面积，因此腐蚀晕圈上的高电阻及其不稳定性造成电接触失效概率大大提高。

Products may be corroded, appearing islands-like spots, after long exposure to severely contaminated environment. A corroded part is composed of a protruding core and a halo around it. Under the core are small pores. Fretting test on the corroded part show that even the thin corroded halos may cause high and unstable contact resistance. With increase of the test cycle, contact resistance decreases, for the corroded being pushed away. Application of stronger force on front surface leads to a lower and more stable initial resistance. Since the area covered by the halos is much larger than that by the cores, the high and unstable contact resistance of the halos is more likely to cause contact failure