Preparation And Tribological Behaviors Of Duplex Treated Multi-component CrN-based Coatings By Plasma Nitriding And Arc Ion Plating

In this study,a series of CrMeN?C?multi-composite coatings?Me=V,Mo?were deposited on DC 53 mold steel by combined plasma nitriding and arc ion plating technique,aiming at the improvement of the anti-galling and wear resistance of clod work molds.The structure,mechanical properties and wear performance of the coatings deposited with different process conditions were systematically studied.The effects of the composition and structure on the anti-galling properties were mainly investigated.The conclusions were summarized as follows:?1?CrVN coatings with different V content were prepared by adjusting the arc current of CrV alloy target.The arc current had less influence on the V content of coatings?7.8¹0.7 at.%?.The prepared coatings were mainly composed of face-centered cubic?Cr,V?N solid solution with?111?preferred orientation.With doping of V element,the microstructure of CrVN coatings became more dense and the hardness was enhanced due to solid solution strengthening.When the arc current of CrV alloy target was 130 A,the highest coating hardness of 2400 HK_0.05.05 was obtained,along with superior wear resistance?WC-Co hard alloy as friction pair?.Compared with CrN coating,the lower surface roughness and generated self-lubricating VO₂ phase improved the anti-galling properties of CrVN coatings.?2?The microstructure and properties of CrVCN coating were affected by the carbon content.The CrVCN coatings prepared with various flow rate of C₂H₂ were mainly composed of?Cr,V??C,N?solid solution phase and amorphous carbon phase.As the flow rate of C₂H₂ increased,the component of soft amorphous carbon increased,resulting in decrease of the hardness of coating.When the flow rate of C₂H₂ was 75 sccm,the adhesion strength of CrVCN coating reached up to 67.10 N.As the flow rate of C₂H₂ increased,the anti-galling properties of the coatings were improved due to graphite-like lubricating phase.?3?The effect of substrate bias on the microstructure and properties of CrMoN coatings were investigated.CrMoN coatings were composed of face-centered cubic?Cr,Mo?N solid solution with?111?preferred orientation.The growth of columnar structure of the CrMoN coatings was inhibited due to the incorporation of Mo.When the substrate bias voltage was-50 V,the hardness and adhesion strength of the coatings reached the highest value of 2397 HK_0.05.05 and 69.5 N,respectively.Consequently,the coatings showed the best wear resistance.The hardness of the coatings decreased with the bias voltage increased,the anti-galling properties of coatings were improved during the sliding process against the aluminum alloy.?4?The carbon doped CrMoN coatings were investigated to further improve the anti-galling properties of coatings.The as-deposited CrMoCN coatings showed a random orientation microstructure.The amorphous carbon content of coatings was increased with the increase of C₂H₂ flow rate.When the carbon content was 40.7 at.%,the coatings showed the best adhesion strength?74.0 N?.The higher carbon content induced loose microstructure on the surface layer of coatings,resulting in the decrease of adhesion strength.The hardness and wear resistance of the coatings decreased due to the carbon dopping,but the anti-galling properties of coatings were.enhancedIn summary,the ternary CrVN and CrMoN coatings showed excellent mechanical properties and wear resistance.While the quaternary CrVCN and CrMoCN coatings showed excellent anti-friction and anti-galling properties.