Microstructure,Mechanical And Tribological Properties Of CrTiAlCN Coatings In Water Based Cutting Fluid

CrAlN,CrTiAlN,CrTiAlCN coatings were deposited on 316 L stainless steels and Si?100?wafer while CrTiAl?C?N composite coatings with different C concentration were deposited on HISI M2 steels by using closed-field unbalanced magnetron sputtering system.CrAl?C?N with different C concentration were deposited on HISI M2 steels and Si?100?wafer by using DC and RF magnetron cosputtering system.The chemical composition,structure,hardness and adhesion strength of the deposited coatings were characterized via appropriate methods.The influences of deposited parameters and tribological conditions on frictional property of the coatings in air and water based cutting fluid were studied.Meanwhile,the wear mechanism was discussed after studing the tribopairs morphology after friction test.The results showed that:1)The main crystal in CrAlN,CrTiAlN,CrTiAlCN coatings was fcc-CrN.With the incorporation of Ti,C element,the hardness of the coatings were decreased from 1233HV0.01 to 1110HV0.01.In the lubrication condition of air,the friction coefficient of the coatings were all in the range of 0.85¹.1.The wear rate of each coatings were increased with the increase of friction velocity.In the lubrication of water based cutting fluid,the friction coefficient of the coatings were lower than that in the air.Futher more,the friction coefficient were decreased obviously with the increase of friction velocity.The lowest friction coefficient was 0.24 for CrTiAlCN coatings while the minimum wear rate was 1.43×10^-7mm³/Nm for CrAlN coatings when friction velocity was 0.4m/s.2)The main crystal in CrAl?C?N coatings was CrN/Cr2N.and the ratio of CrN/Cr2N were decreased while the amorphous carbon were increased with the increase of C concentration.The hardness of CrAl?C?N coatings were increased first and then decreased with the increase of C concentration.The highest value of hardness was 1095HV0.01 when C content was 50.28 at.% for these CrAlCN coatings.The friction coefficient of the CrAl?C?N coatings were decreased with the increase of C concentration both in air and in water based cutting fluid.In the lubrication condition of air,the friction coefficient decreased from 1.06 to 0.34.In the lubrication condition of water based cutting fluid,the friction coefficient decreased from 0.60 to 0.11.CrAlCN4 coatings have the lowest specific wear rate both in air and water based cutting fluid on count of its low friction coefficient.3)CrTiAlCN coatings are mainly comprise of fcc-CrN with few fcc-TiN/AlN.And the amount of fcc-CrN had been decreased and was displaced by a-C with the increase of C concentration.The hardness of these coatings raised with C incorporation into CrTiAlN with the highest hardness of 2999 HV0.05 with the C content of 22.5 at.%.The value of the critical load of CrTiAlN coatings were 76 N.With the increase of C concentration,the adhesion strength were weakened all through.The friction coefficient had reduced from 1.24 to 0.37 in the tribology environment of ambient air with the increase of C content.In the tribology environment of water-based cutting fluid,the friction coefficient had reduced from 0.60 to 0.53.In ambient air,the minimum value of the specific wear rate was 9.82×10^-7mm³/Nm for CrTiAlCN5.And in the tribology environment of water-based cutting fluid,the minimum value of the specific wear rate was 1.15×10^-6 mm³/Nm for CrTiAlCN5.