摘要
利用外观检查、X射线检查、金相切片分析、扫描电子显微镜分析和光电子能谱分析等手段对压力变送器的PCB的腐蚀失效现象进行了分析。结果表明,该PCB的失效原因为:三防漆与板面结合不良、内部存在裂纹、涂覆不均匀和局部未见明显的三防漆覆盖等,导致其对空气中水汽的防护能力减弱,造成了焊点在较高的残留离子、持续电场和空气中水汽的共同作用下发生了电化学反应,从而生成了焦黄色或蓝绿色的腐蚀物。
The corrosion failure phenomenon of PCB for pressure transmitter is analyzed by means of visual The results show that inspection, X-ray inspection, microsection analysis, SEM and EDS the reasons for the failure of PCB are as follows： the poor bond between conformal coating and board, internal crack, uneven coating and the lack of obvious conformal coating in local position result that the protective ability of PCB to water vapor in the air is weakened, and then cause that the electrochemical reaction of the solder joint occurs under the coaction of high content of residual ions, the continuous electric field and the water vapor in the air, which results that the yellow or blue-green corrosion forms.
出处
《电子产品可靠性与环境试验》
2017年第2期19-23,共5页
Electronic Product Reliability and Environmental Testing
