Characteristics of Diffusion Annealing Between Martensitic Stainless Steel and Nickel in the Form of Coating and Foil

Characteristics of interaction between martensitic stainless steel type AISI 410 with nickel in the form of coating layer and foil were investigated. Nickel was coated on AISI 410 substrate by electroplating in various thicknesses (6-16 μm). The 300-μm-nickel with purity of 99.9% was employed as a foil layer. All specimens were annealed in the temperature range of 700-900 °C for 5, 10, 15, and 60 min. Optical microscopy, SEM and EPMA analyzer were carried out in order to characterize the interdiffusion behavior differences between nickel and AISI 410 while using nickel layer in different form. It was observed that the thickness of nickel coating had a minor effect during annealing on the interaction between Ni and substrate at faying surface. However, the results show that the interaction of nickel coating layer with base material is much faster than foil layer during annealing process. This study suggests that the coating layer diffused faster to the substrate than foil layer; moreover, in the former case, heavy outer load was omitted. The concentration profiles were plotted for two cases. Although in case of using layer in the form of coating the annealing time was relatively short (5-15 min), it was observed that the concentration profiles for main elements had shapes close to the theoretical curve. For various thicknesses (6-16 μm) of Ni coating, the experimental results show that the interaction at faying surface caused the thickness of nickel coating growth. The diffusion zone width was plotted against the annealing temperature and time for both cases and the growth of the diffusion zones was compared.