Molybdenum Disulfide (MoS2) Coating on AISI 316 Stainless Steel by Thermodiffusion Method

Molybdenum disulfide (MoS₂) is one of the most widely used solid lubricants applied in different ways on the surfaces under friction. In this work, AISI 316 austenitic stainless steel was coated with MoS₂, using thermo-diffusion method at different temperatures and times. Coatings properties were investigated using SEM, EDX, XRD and FTIR, Hardness Tester and Roughness tester. The results illustrated the formation of a uniform layer on the surface, containing MoS₂ and MoO_3–X phases. The thickness, grain size and the hardness of the coatings were 20-50 μm, 400-1000 nm and 350- 550 HV respectively. Friction tests carried out using ball-on-disc method under normal loads of 10 N under ambient conditions showed values of the friction coefficient 0.30-0.40. In addition, the kinetics of diffusion layers between the substrate and the coating were also investigated. It was found that there at steady temperature there is a parabolic relationship between the thickness of the diffusion layer and the treatment time. The activation energy for the process was estimated to be 143 kJ mol^-1. Depending on the treatment time and temperature, the thicknesses of diffusion layer varied between 0.5 and 2.5 microns.