The Preparation And Properties Of Duplex Treated TiN/TiCN Multilayer Coatings By Plasma Surface Nitriding And Multi-arc Ion Plating

In order to further optimize the deposition process of TiN/TiCN coating,and improve its practical performance,the duplex treated TiN/TiCN multilayer coatings were deposited on DC53 die steel by plasma surface nitriding and multi-arc ion plating.Three TiN/TiCN coatings with different structures were designed and characterized by XRD,SEM,EDS,TEM,scratch test,friction and wear experiment,the composition,structure,bonding adhesion strength and tribological properties of different coatings were analyzed.The effects of different deposition process on the properties of TiN/TiCN coatings were investigated systematically.In addition,the effect of plasma nitriding and nitrocarburizing treatment on the properties of TiN/TiCN coatings are studied.The conclusions were summarized as follows:The TiN/TiCN coatings named A1,A2 and A3 with different alternating structures were deposited on DC53 substrate.The results showed that those cotings contained mainly the Ti(C,N)solid solution phase and amorphous carbon phase.A few large particles and pits were observed on the coating surface and A3 coating exhibited maximum surface roughness,which had significant effect on coating application.A2 and A3 multi-layer coatings showed better adhesion than A1 bilayer coating.The wear resistance of the coatings showed different under different friction materials.The wear of coatings was more serious during grinding abrasion with steel ball.On the whole,the wear resistance of A2 coating was poor.Three composite TiN/Ti CN coatings named B1,B2,and B3 were deposited on the DC53 substrate after plasma nitriding with the same deposition process as those of A1,A2,and A3,respectively.After ion nitriding,the phase structure of DC53 substrate surface was changed to Fe3 N and ?'-Fe4 N phase from the ?-Fe phase.The hardness of substrate increased from 607.1 to 1041.2 HV0.05.The adhesion strength of the coatings was improved,and that of B1,B2 and B3 coatings was 18.0 N,26.5 N and 30.5 N,respectively.The wear results showed that the B1 and B3 composite coatings exhibited better wear resistance.DC53 substrate after plasma nitrocarburizing,the surface phase was mainly Fe3 N phase and ?'-Fe4 N phase.Three composite TiN/TiCN coatings named C1,C2,and C3 were deposited on the DC53 substrate after plasma nitrocarburizing with the same deposition process as those of A1,A2,and A3,respectively.All coatings showed nano-columnar structure througth TEM cross-section analysis,and the thickness of TiN sublayer directly affected the growth of columnar crystal.The C1 coating exhibited smaller grains and denser structure.The existence of ?'-Fe4 N phase provided strong support for TiN/TiCN coating,and provided nucleation particles for epitaxial growth of TiN coating,which improved the hardness and adhesion of composite coatings remarkably.