Online Measurement Of Stress During Nickel Electroplating Based On Fiber Bragg Grating

Electroplating stress is very universal in plating coating, on the one hand, it makes important influence on quality and performance of the plating coating, on the other hand, it also can indicate the internal structure change of the plating coating. Obviously, measuring and researching the stress in the process of electroplating has very important significances.Optical Fiber Bragg Grating(FBG)has lots of advantages when compared with tradition conductors, such as small size and quality, strong stability, resistant to corrosion and high degree multiplexing. When there have some disturbances acting on FBG, the FBG center wavelength has a shift, and we can infer the disturbances by calculate the shift. This study explores a new way to measurement the coating stress is based on the feature of FBG sensors.The main job of this paper includes three aspects:(1)We introduce the sensing model under the uniform axial stress and lateral stress based on the stress and strain sensing principle of fiber Bragg grating, and provide theoretical basis for application in electroplating stress by synthesizing its features.(2)We analyze two kinds of electroplating residual stress measurement methods, mechanical release measurement method and nondestructive measurement method,which are the most widely applied at present. And compare their advantages and disadvantages with the method that we used in this study, so that we can confirm the advantages of this thesis project.(3)A new method of using FBG as stress sensor to monitor electroplating stress real time when it was electroplated has been proposed and three groups of control experiments which in different temperature and main salt concentration by simple variable method have been done, then the nine groups experimental data were obtained after the spectrum analyzer recorded the FBG center wavelength and shift directions in real time. The rightness and feasibility of the method were confirmed when we demonstrated the experiments result combined with the theoretical analysis.The results indicate that FBG can monitor electroplating stress, it has the advantages of real-time and literality, broadens the application of FBG in sensing field.