Abstract
Over the past years,hard wear resistant TiN coatings deposited by magnetron sputtering have gained increasing importance in the field of decorative and cutting tool coatings. With the ongoing trend to multifunctional operating cutting tools,new solutions in the design of tools are demanded.The alloying of TiN coatings with additional elements,for instance,can effectively enhance hardness,wear resistance and so on.Both TiAlN and TiSiN coatings,well-studied nitride systems,yield superior oxidation resistance,and extend the life of cutting tools by significant margins in comparison with TiN coatings.Numerous research activities focus on TiAlN,TiSiN systems, whereas limited efforts have been made to characterize TiMoN coatings.Low coefficient of friction is a common property in various Mo-containing coatings that can react with oxygen in the air into Magneli phase(M0O_3).The effects of Mo alloying on mechanical properties and wear resistance of TiN-based coatings remain to be investigated.TiMoN composite films with various Mo concentrations were deposited using RF reactive magnetron sputtering and characterized by SEM,EDS,XRD, nano-indentation and wearing tester.The results show that TiMoN coatings have fcc structure. When atomic fraction of Mo in total metallic elements(X) is less than 68.37%,a TiMoN solid solution was formed by dissolution of Mo into the TiN lattice;when X is more than 68.37%,a TiMoN solid solution was formed by dissolution of Ti into the Mo_2N lattice.With Mo contents increase,preferential orientation change,microhardness increase significantly,the coefficient friction and grain size decrease, friction and wear of TiMoN coatings are excellent.Low coefficient friction can be primarily attributed to the formation of lubricious MoO_3 on the wear track surface in dry sliding wear conditions.The principles of a crystal chemical model relating the lubricity of complex oxides to their ionic potentials can explain this mechanism.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
