This study employed a combination of direct current magnetron sputtering and high-power pulse magnetron sputtering techniques to deposit Cr/Cr2N multilayer coatings on Cr-Ni-Mo-V steel substrates that had undergone mirror polishing, pickling, nitriding, and grinding. The microstructure, mechanical properties, and adhesion of the coatings were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), hardness testing, indentation testing, and scratch testing. When the roughness of substrates with the same hardness increased from 0.086μm to 0.744μm, the adhesion of the coating, Lc2, decreased by up to 41%. Substrates subjected to plasma nitriding exhibited the highest roughness. However, plasma nitriding refined the grains while maintaining a coherent interface between the coating and the substrate. Due to the combined effects of substrate load-bearing capacity and grain refinement in the coating, both the fracture toughness (by 54%) and adhesion (by 55%) of the coating were significantly enhanced, effectively compensating for the degradation in coating performance resulting from the increased roughness. The bearing capacity and ability to promote crystallization of the substrate surface are more crucial factors compared to its roughness.
 

surface feature,adhesion,hardness,surface roughness,multilayer