Study On The Preparation Process And Mechanical Properties Of Plasma Nirtrocarburizing And AlCrN Duplex Coatings

In this dissertation, the AlCrN multilayer films with different deposition temperatures and different nitrogen partial pressure of adhesion layer were deposited on the T10 steel and SKD11 steel with and without nitrocarburizing by Arc ion plating(AIP) technique. The effect of depositing parameters on compositiosn, phase structure,cross-sectional and surface microstructures, hardness, adhesion strength and tribological properties of the duplex coatings were investigated by the means of X-ray diffraction(XRD), Scanning electron microscopy(SEM), Transmission electron microscope(TEM), Optical microscope(OM), Energy dispersive spectrometers(EDS),Nanoindentation tester, Rockwell indentation tester and Scratch tester. The conclusions were summarized as follows:(1) The nitrocarburizing pretreatment was used before AlCrN films deposited on the T10 steel to create the nitrocarburizing-AlCr N duplex coatings. The nitrocarburizing layer provided a transition layer between the substrate and AlCrN coating.Compared with the single AlCr N coating, the adhesion strength of the duplex coatings increased by 10 N, and the friction coefficient decreased from 0.6 to 0.4.(2) The AlCrN films were deposited on the SKD11 steel with or without nitrocarburizing layer under deposition temperature of 350?, 400 ? and 450 ?.With the increasing of deposition temperature, the microstructures of the AlCrN coating became denser. The deposition efficiency were 0.533 ?m/h?0.587 ?m/h?0.674 ?m/h, which increased with deposition temperature from 350 ? to 450 ?. At the same deposition temperature, the wear resistance of the duplex coating was higher than that of the single AlCr N coating by 3~4 times.(3) The AlCrN films were deposited on the SKD11 steel with or without nitrocarburizing layer under different nitrogen partial pressure of bonding layer,which varied from 0.8Pa, 2Pa to 3Pa The formation of the preferred orientation of{200}CrN of the adhesion layers improved the adhesion strength of the duplex coatings,which increased from 48 N to 65 N. The improved adhesion strength contributed to the improvement of hardness and wear resistance of the duplex coatings.