ENHANCING ADHESION STRENGTH AND WEAR PERFORMANCE OF ALCRN COATING ON COOL-WORK TOOL STEEL THROUGH INTRODUCING CRNX ADHESION LAYER

摘要

Hard thin coating directly deposited on soft steel substrate often suffers low adhesion strength and load-bearing capacity. In this work, CrNx-type adhesion layers (ALs) were introduced between hard AlCrN coating and soft cool-work tool steel substrate to enhance the adhesion strength and wear performance. The microstructure of CrNx ALs prepared with different nitrogen pressure and its influence on adhesion strength and tribological properties were investigated. The results show that with the nitrogen pressure increase from 0.5 Pa to 3.0 Pa, the phase transformation sequences occurring in ALs are: Cr + Cr2N -> Cr2N + CrN -> CrN. The adhesion strength increases with the increase of nitrogen pressure due to the formation of CrN which provides better load support resistance than the fragile Cr2N and soft Cr. In addition, the adhesion strength of the samples with ALs is always higher than that of the one without ALs. The improvement of adhesion strength for samples with CrNx-type ALs is beneficial for improving wear resistance, especially at high wearing loads.

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