Study On The Microstructure Regulation And Properties Of TaN_x/MoN_x Nano-Multilayer Films

With the rapid development of aerospace,automobile industry,special machinery manufacturing and other fields,the demand for the application of green processing and manufacturing technology represented by high-speed dry cutting continues to increase.However,due to the high friction and high temperature of high-speed dry cutting The significant decline in service life has become a bottleneck problem that limits the application of high-speed dry cutting technology.Therefore,it is particularly important to develop a hard coating with high hardness and low friction coefficient in a wide temperature range.In view of this,on the basis of MoNbased films with low-temperature and high-temperature self-lubricating properties,MoNx/TaNx nano-multilayer films were prepared by introducing the valence electron concentration control element Ta to try to improve the seriousness of the films caused by the decrease of H/E in the medium temperature region.The problem of self-lubricating loss caused by abrasive wear,and considering the potential impact of the structural performance characteristics of TaNx monolayer film on the tribological behavior of TaNx/MoNx nano-multilayer films,in this paper,reactive magnetron sputtering technology was used to prepare TaNx thin films and TaNx/MoNx nanomultilayer films with different structures by changing the flow rate of reactive gas N2,and studied the influence of N2 flow rate on the microstructure,mechanical and tribological properties of the films Construct the relationship between the hardness,H/E value and oxidation behavior of the film and the tribological behavior in the wide temperature range,and discuss the friction and wear mechanism of the film in the wide temperature range.The research results show that:The phase structure of TaNx films changed from fccTaN0.1→hcpTa2N+fccTaN mixed phase with the N2 flow increased from 4sccm to 20sccm.With the increase of N2 flow rate,the hardness of TaNx film increases from 25.4GPa to 46.8GPa.The hardness of the TaNx films prepared when the N2 flow rate is higher than 12 seem is higher than 45GPa,showing superhardness;the H/E values are higher than 0.11,indicating that the TaNx thin films have good toughness.The friction coefficient of TaNx film at room temperature is generally high,ranging from 0.76 to 0.96,and the friction coefficient at 400℃ and 600℃ decreases significantly,and the lowest drops to 0.24.frictional lubricationThe phase structure of TaNx/MoNx nano-multilayer films changed from hcpTa2N+bccMo mixed phase→fccTaN+fccMo2N mixed phase as the N2 flow increased from 5sccm to 17sccm.With the increase of N2 flow rate,the hardness of TaNx/MoNx nano-multilayer films increased from 16.4GPa to 44.8GPa.The H/E of the TaNx/MoNx nano-multilayer films prepared under the N2 flow rate exceeding 9 sccm is close to 0.1,which is 25%higher than that of the single-layer MoN film.The room temperature friction coefficient of TaNx/MoNx nano-multilayer films is relatively high,and its value varies from 0.84 to 1.19.The friction coefficient at 400℃ and 600℃is significantly lower than that at room temperature.The decrease in friction coefficient is due to the formation of Ta2O5 and magnéli phase oxide Mo4O11,which have lubricating and antifriction effects,on the surface of the wear scar at medium and high temperatures.