Optimizing the anti-erosion performance of ZrAlSiN coatings by adjusting nitrogen flow rate

To optimize the anti-erosion performance of ZrAlSiN coatings, a series of ZrAlSiN coatings were fabricated at different nitrogen flow rates by the means of magnetic filtered cathode vacuum arc technology. The effects of the nitrogen flow rate on the microstructure and mechanical properties of ZrAlSiN coatings were systematically investigated. Their sand erosion resistance and corresponding damage mechanisms were elaborately explored as well. The results showed that the increased nitrogen content in ZrAlSiN coatings promoted the crystallinity and the formation of metal nitrides. With increasing nitrogen flow rate, the hardness and residual stress of coatings increased initially and then decreased, while the adhesion strength displayed an opposite variation trend. Therein, the ZrAlSiN coating prepared at 100 sccm nitrogen flow rate exhibited the best sand erosion resistance due to the optimal combination of high hardness and adhesion strength, as well as appropriate residual stress. As the nitrogen flow rate increased, the erosion damage mechanism of ZrAlSiN coatings transformed from ductile to brittle characteristics. The N25 coating predominantly displayed ductile damage characteristics, including deformation, cutting and plough, while the N50, N75 and N100 coatings were more prone to brittle spalling as a result of the initiation and propagation of cracks.