合金化效应对Ni-W镀层微观组织和力学性能的影响

The effect of processing technology and microalloying addition on the microstructure and mechanical properties of Ni-W coatings prepared by electrodeposition was studied. The surface morphology, microstructure, and tensile properties of Ni-W coatings were studied with a small W addition of less than 2.0at%. The results show that the Ni-W coatings have a single-phase fcc structure. By increasing the W content, the surface morphology of the coatings varies from the grooves between the coarse pyramid structures to uniformly distributed micropores. At the same time, the intensity of Ni(220) diffraction peak of the coatings is also gradually weakened, with the reduction of surface roughness and the grain size. There is a critical W addition of about 1.0at%, where the yield strength of Ni-W coating increases sharply from ~1.0 GPa at the W addition <1.0at% to ~2.0 GPa at the W addition >1.0at%. However, the tensile elongation is insensitive to the W content, which keep almost unchanged within the studied W addition range. In addition, strain hardening capacity of the coatings is also stable with the W content. In this work, the mechanical properties of Ni-W coating with micro-addition of W are optimized through manipulation of microalloying effect on the surface defect and microstructure.