Abstract:In order to improve the tribological properties of the coating in vacuum or high temperature,CrN and CrN/Ag coatings were deposited on stainless steel substrates by medium frequency DC magnetron sputtering system.A variety of technologies were employed to characterize the composition and structure of the coatings,including scanning electron microcopies,transmission electron microscope,X-ray diffraction.The mechanical properties and friction behaviors of as-deposited coatings were investigated by scratch tester,nanoindentation tester and friction and wear tester.The results show that the hardness and load-carrying capacity of CrN/Ag coatings decrease with the addition of Ag,but the bonding strength increases.The friction coefficient of CrN and CrN/Ag coatings decreases with increasing temperature at high temperature in vacuum.CrN coating depends on reducing shear strength and resistance by softening the coating during sliding,thereby reducing the friction coefficient.However,CrN/Ag coating can form Ag lubricating film on the friction surface induced by thermal driving force produced at high temperature,thereby reducing the friction coefficient.CrN coating participates in friction process relying on their shear properties,while CrN/Ag coatings are able to keep self-lubrication and sustained lubrication at high temperature in vacuum,indicating their potential application as a self-lubricating coating for tribo-components.
