Achieving high hardness and low friction at elevated temperatures for nitride-based hard coatings has substantial scientific interest and application significance.In this study,AlCrN/Cu coatings were deposited by a hy...Achieving high hardness and low friction at elevated temperatures for nitride-based hard coatings has substantial scientific interest and application significance.In this study,AlCrN/Cu coatings were deposited by a hybrid PVD technique combining arc evaporation from an Al_(60)Cr_(40) target and magnetron sputtering from a Cu target in a mixed Ar and N_(2) atmosphere.The microstructure,oxidation behavior,and tribological properties of the coatings were investigated.AlCrN/Cu coatings show a dual-phase structure of(Al,Cr)N solid solution and Cu metallic phase.Excessive sputtering power of the Cu target induces the disintegration of interlayer interfaces of the nano-multilayered geometry,accompanied by a decline in hardness from above 30 GPa to 22.7 GPa.Moreover,the formation of fine CuO grains on the coating surface is conducive to reducing the friction coefficient of AlCrN/Cu when exposed to air at high temperatures.The AlCrN/Cu coating with a sputtering power of 0.5 kW obtains a friction coefficient of 0.39±0.05 after pre-oxidation at 800℃,distinctly lower than that of AlCrN,which exhibits a friction coefficient of~0.65.The further transformation of CuO to cubic Cu(Al,Cr)_(2)O_(4),which stems from the solid-state reaction of CuO,Al_(2)O_(3),and Cr_(2)O_(3),would cause a rise in friction coefficient and wear loss.The mechanism of oxidation and tribological behavior of the AlCrN/Cu coatings related to the temperature and Cu content was discussed.展开更多
基金financial support by the National Natural Science Foundation of China under Grant Nos.51801032 and 51875109financial support of the National Key R&D Program of China(Grant No.2017YFE0125400)。
文摘Achieving high hardness and low friction at elevated temperatures for nitride-based hard coatings has substantial scientific interest and application significance.In this study,AlCrN/Cu coatings were deposited by a hybrid PVD technique combining arc evaporation from an Al_(60)Cr_(40) target and magnetron sputtering from a Cu target in a mixed Ar and N_(2) atmosphere.The microstructure,oxidation behavior,and tribological properties of the coatings were investigated.AlCrN/Cu coatings show a dual-phase structure of(Al,Cr)N solid solution and Cu metallic phase.Excessive sputtering power of the Cu target induces the disintegration of interlayer interfaces of the nano-multilayered geometry,accompanied by a decline in hardness from above 30 GPa to 22.7 GPa.Moreover,the formation of fine CuO grains on the coating surface is conducive to reducing the friction coefficient of AlCrN/Cu when exposed to air at high temperatures.The AlCrN/Cu coating with a sputtering power of 0.5 kW obtains a friction coefficient of 0.39±0.05 after pre-oxidation at 800℃,distinctly lower than that of AlCrN,which exhibits a friction coefficient of~0.65.The further transformation of CuO to cubic Cu(Al,Cr)_(2)O_(4),which stems from the solid-state reaction of CuO,Al_(2)O_(3),and Cr_(2)O_(3),would cause a rise in friction coefficient and wear loss.The mechanism of oxidation and tribological behavior of the AlCrN/Cu coatings related to the temperature and Cu content was discussed.
