手机中电触点的失效分析

研究了大量失效手机中的镀金触点后发现，触点表面污染是造成电接触故障的主要原因之一. 污染物形貌复杂，且主要集中在印制电路板的触点一侧，成分涉及C、O、Si、Al、S、Cl、Na、Ni等很多元素. 污染物来自于环境中的尘土和微动磨损. 采用图像处理技术计算污染物覆盖面积百分比，划分触点污染程度为5级. 污染等级越高，污染物平均厚度越厚，磨损区范围越大. 污染触点上的接触电阻60％超过设计标准，最大接触电阻达4?Ω. 电接触不可靠造成手机可靠性下降.

Analysis on the Electric Contacts Failure in Mobile Phones

The contamination on contact surfaces was found to be one of the main reasons to cause electric contact failure by analyzing lots of gold plated contacts in failed mobile phones. The contaminants are with complex morphology, and mainly concentrated on the contacts on printed circuit boards. The element compositions of contaminants include C, O, Si, Al, S, Cl, Na, Ni etc. They come from the dusts in environment and wear debris by fretting. Image process technology was adopted to compute the coverage areas percentage of contaminants; it concluded that the contamination degree on contacts was classified into 5 levels. As the contamination levels increased, the average thickness of the contaminants raised and the wear zones also expanded. 60% of the contact resistance tested on contaminated zones was higher than the design limitation. The maximum contact resistance attained to 4?Ω. The unreliable electric contact made the reliability of mobile phones degraded.