Tribological Performance Of CrTiAlN PVD Coatings Under Abrasive Particles Lubrication

With the rapid development of modern mould manufacturing technology,more and more high performances are requiremented of the mould.It can effectively improve the performance and its working life,by deposition the hard thin film on steel surface.The CrTiAlN coatings are deposited on the surface of nitriding and un-nitriding Cr12MoV cold work die steel by the closed field unbalanced magnetron sputtering ion plating(CFUMSIP)technology.The phase structure of the coating,chemical composition and microstructure,microhardness,film/bonding strength were characterized using XRD,SEM and EDS,rockwell hardness tester and scratch tester.And the friction and wear resistance are tested under the condition of dry friction and wear particle lubrication friction.Some significant results were obtained as follows:The thickness of CrTiAlN coatings nearly 2 ?m,and have smooth dense and uniform surface particles,the cross-section microstructure shows the structure of the columnar crystal,nitriding sample film were small angle to growth of the columnar crystal,while un-nitriding sample was in vertical growth.The main crystal phase are CrN and TiN,both have strong(200)crystal plane and weaker(111)preferred orientation.Scratch method measured not nitriding/adhesion for 46N kind of membrane,membrane/adhesion of nitriding specimen for 57N,significantly higher than the un-nitriding sample;The test results are consistent with the indentation method.Matrix nitriding can enhance the bonding strength of the film.Matrix nitriding treatment can also improve CrTiAlN film abrasion resistance.Dry friction,the wear mechanism of the membrane including adhesive wear,abrasive wear and friction properties of thin film also related to the load,sliding velocity and other test conditions.Grinding grain of the lubrication condition,wear thin film is mainly due to the extrusion of abrasive,cutting effect and aggregation,cause the extension of film internal micro cracks,reduce lubrication to wear.Wear and tear on membrane associated with abrasive particle size,load,the wearness of the films mainly occurs in the running-in stage,with the increase of wear time,wear rate decreased.