Effect Of Substrate Bias Voltage On Structural And Properties Of MoS₂-Ti And MoS₂-Ti/TiN Composite Films

MoS2,as a solid lubricant with excellent performance,is widely used in machining,electronics,aerospace and other fields.However,the use of pure MoS2 films due to the susceptibility to wet oxidation to lubricate their applications has been limited.At present,MoS2 based composite films are mainly prepared by magnetron sputtering co-deposited doped metal to solve this problem.During the magnetron sputtering deposition process,the substrate negative bias voltage has a significant effect on the composition and structure of the film.Therefore,based on MoS2-Ti composite films with good comprehensive performance,MoS2-Ti and MoS2-Ti/TiN composite films were prepared by changing the substrate negative bias voltage and adding TiN interlayers,and then the effect of substrate negative bias voltage on the microstructures,mechanical and tribological properties of composite films,and the influece of TiN interlayer on the structure and properties of MoS2-Ti/TiN composite films were studied.Research indicates:With the increase of substrate negative bias voltage,the MoS2-Ti composite film transition from crystalline to amorphous state.When the substrate negative bias voltage is 30V,the MoS2-Ti composite film has MoS2 nanocrystalline,intermittently embedded in the amorphous structure,when the negative bias voltage is greater than 50V,the MoS2-Ti composite film completely transformed into an amorphous structure;With the increase of negative bias voltage,S/Mo of MoS2-Ti composite film gradually decreased,from 1.7 at negative bias voltage of 30V to 1.3 at negative bias voltage of 110V,and the thickness of MoS2-Ti composite film gradually reduced from 3.82?m to 3.26 ?m.A part of the Ti atoms in the MoS2-Ti composite film replaces Mo atoms in the MoS2 to TiS2,and another part enters the layered structure of the MoS2.The MoS2-Ti/TiN composite film consists of a TiN columnar layer with a thickness of about 400 nm and a dense,amorphous MoS2-Ti layer.The hardness of MoS2-Ti and MoS2-Ti/TiN composite films increases with the increase of negative bias voltage.The hardness of MoS2-Ti composite films increases from 8.8 GPa at negative bias voltage of 30V to 9.8GPa at negative bias voltage of 110V.The hardness of the MoS2-Ti/TiN composite film increases from 9GPa at a negative bias of 30V to 10.3GPa at a negative bias of 90V.At room temperature,the friction coefficient of MoS2-Ti and MoS2-Ti/TiN composite films are stable at 0.05-0.10 and 0.03-0.06,respectively,when the negative bias voltage is between 30V and 90V,and the friction coefficient of the composite film reaches the minimum when the negative bias voltage is 70V,which is 0.05 and 0.03 respectively.In the high temperature environment of 350 ?,the friction coefficient of MoS-2-Ti composite films prepared under different substrates negative bias voltage were significantly lower than that at room temperature.The addition of TiN interlayer improved the tribological properties of the composite films.The wear mechanisms of MoS2-Ti and MoS2-Ti/TiN composite films at different temperatures are dominated by abrasive wear and adhesive wear.