Investigation of structural, mechanical and tribological properties of TiNi/MoS2 coatings deposited by magnetron sputtering method

The aim of this study is to produce functional layered solid lubricant coatings as a new type in literature by depositing the solid lubricant MoS2 films with TiNi films having shape memory feature which has become widespread in recent years. It is aimed to improve the sudden impact resistance, vibration damping and initial friction coefficient of MoS2 films. Using the closed area unbalanced magnetic field sputtering method (CFUBMS) as the coating method, the said functional coatings were grown on 52100 bearing steel and D2 tool steel base materials. The deposited films were carried out at different levels according to the Taguchi experimental design method. TiNi films must be crystalline in order to show shape memory. However, the TiNi films produced are known to be deposited in an amorphous structure and require proper heat treatment to obtain a crystalline structure. The TiNi coating was heat treated at 550°C for 1 hour under suitable conditions for crystallization. After obtaining the desired crystalline structure (martensite phase at room temperature), MoS2 films which are solid lubricant layer were deposited on the surface of the samples. Thus, functional layer TiNi/MoS2 coatings were deposited. Structural properties of TiNi / MoS2 films were determined by XRD, SEM tribological properties in atmospheric conditions Pin-on-disc wearing tester and mechanical properties by Vickers microhardness tester in atmosphere. TiNi/MoS2 films were found to vary depending on sputtering parameters the chemical composition and film thickness. It was determined that the abrasion rates of the samples differed according to the spatter parameters and base material and the lowest abrasion rate was found to be 0.35x10-5. It was also found that the highest hardness value was 436 Vickers and the lowest coefficient of friction was µ= 0.025. It has been observed that the coating parameters for the wear resistance of the films have a combined effect over each other.