Abstract:TiAlN,CrAlN and TiCrN coatings were prepared by using DC and RF magnetron cosputtering system.The mechanical properties of the coatings and their tribological properties in air and in water based cutting fluids were investigated,and the wear mechanisms were also revealed.It is found that the Al elements exist in TiAlN and CrAlN coatings in the form of solid solution.The corresponding microhardness of the three coatings are HV7193,HV10225 and HV9735 respectively.The steadystate friction coefficient of three coatings sling against SUS440C steel balls is 1.25,114 and 131 in air,respectively,and the wear mechanisms of TiAlN and CrAlN coatings are mainly oxidation wear,while the wear mechanisms of CrTiN coating mainly is abrasive wear.The friction coefficient in water based cutting fluid is obviously reduced,and the steady friction coefficient was 044,047 and 077 respectively,whilst the scratches on the wear scars are intensified,therefore the corresponding wear mechanism is mainly abrasive wear.