Residual Stress In Electrodeposited Nickel Coating Characterized By Instrumented Nanoindentation

With the development of science and technology, the application area in the electrodeposition coating have being expanded. Because the electrodeposited coating is widely used and its needs is becoming larger, the study on the properties of the coating is becoming a important subject. Residual stress in the coating is inevitable, and it has strongly effect on the qualities and properties, therefore it is necessary to study the residual stress in the electrodeposited nickel coating. Because of the high load and displacement resolution in nanoindentation technology, which can continuously record the change of load-displacement during loading and unloading, nanoindentation technology is fit to study of the coating, especially the mechanical properties. In this master thesis, the residual stress in electrodeposited nickel coating is characterized by instrumented nanoindentation.The investigations of this master thesis are divided into two parts. In the first part, the residual stress in electrodeposited nickel coating is measured by the known instrumented nanoindentation theory model. In the second part, a new theory model is proposed for the determination of residual stress in electrodeposited nickel coating using instrumented indentation.At the beginning of this article, related research background and research status are introduced. Then measurement methods of the residual stress are reviewed, and the background about this master thesis is also introduced. Secondly, the principal of electrodeposited and measurement for mechanical properties by instrumented nanoindentation are introduced. Thirdly, the known theory models and their relationship for the determination of residual stress using instrumented indentation are introduced, according to these theory models residual stresses in five kinds of nickel coating are determined from the P-h curves obtained by nanoindentation experiments. By comparing the measurement results with those of XRD method, we find that the results whose depth at the interface of film/substrate systems are more exact. Another important work in this master thesis is the detailed introduction of extracting a theory model for the measurement of residual stress in electrodeposited nickel coating by instrumented indentation according to the equation of the influence for substrate to measurement hardness in nanoindentation experiment and dimensionless analysis.