散热片铆接引脚的腐蚀变色失效原因  

Failure Reason of Corrosion Discoloration of Heat Sink Riveted Pin

作　　者：姚彦 刘燕芳 于全耀 潘启智 YAO Yan;LIU Yanfang;YU Quanyao;PAN Qizhi(Failure Analysis Lab,Delta Electronics(Jiangsu)Co.,Ltd.,Suzhou 215200,China)

机构地区：[1]中达电子(江苏)有限公司失效分析实验室,苏州215200

出　　处：《腐蚀与防护》2021年第7期86-90,共5页Corrosion & Protection

基　　金：中国博士后科学基金(2017M621849)。

摘　　要：某产品中引脚经高温高湿试验,出现不同程度变色和腐蚀破损现象。采用宏观、微观形貌观察及能谱分析,镀层截面切片分析,对引脚表面镀层腐蚀失效原因进行分析。结果表明:镀层表面变色物质以铁的氧化物为主。镀层存在孔隙、裂纹等通道,使环境中氧气、水与基材接触,致使镀层出现鼓起和破裂等现象。镀层中夹杂的非金属元素碳与金属元素铁形成原电池,加速Fe的腐蚀。此外,镀层厚度存在差异,防护能力不一,因而产品呈现不同程度腐蚀。为防止此类失效再次发生,提出了镀层的改善工艺。Pins riveted with heat sink of a product had different degrees of discoloration and corrosion failure after high temperature and high humidity test.Macroscopic and microscopic observation with energy spectrum analysis were carried out on the corroded coating of pin,the cause of corrosion failure of the coating was analyzed.The results showed that the surface of pin coating was heavily corroded around the edges,the discoloration area of coating was mainly Fe oxide.Oxygen and water entered into coating via pores,cracks and other channels,and then oxidation corrosion of substrate Fe occurred,resulting in coating appearance bulging and cracking failure phenomena,etc.The C nonmetal inclusion in the coating facilitated the galvanic effect with metal element Fe and accelerated oxidation corrosion of Fe.In addition,differences in coating thickness led to different protection ability,so the product showed different degrees of corrosion.In order to prevent this kind of failure from happening again,the improvement process of the coating was proposed.

关 键 词：铆接引脚 镀层 腐蚀 失效分析 夹杂物 

分 类 号：TG174[金属学及工艺—金属表面处理]