Laser cladding process of Cobalt and Nickel based hard-micron-layers on 316L-stainless-steel-substrate

Abstract

ABSTRACTIn the present study, two different types of coatings such as Cobalt (Co-Cr-W-C) and Nickel (Ni-Cr-B-Si-C) based layers have produced using a high power of Ytterbium-doped yttrium aluminum garnet (Yb:YAG) disk laser on 316L stainless steel substrate. Then the coatings were analyzed to expose their phase characterization, microstructure, and hardness using X-ray diffraction analysis, electron microscopes and microhardness tester. Further, tribo-test has performed through a ball-on-plate machine to analyze the wear properties of coatings. Besides, worn-surfaces of cladding and surface roughness have examined. The results showed that both Cobalt and Nickel based cladding have exhibited a dendrite homogeneous structure with some changes in shape and grain size due to higher cooling rates. XRD results indicate that the mixing of a γ-Co peak with other metastable phases such as Cr7C3 and Cr23C6 were noticed on Cobalt coating and γ-Ni rich matrix was the most dominant peak in Nickel-based coating. Microhardness of the cladding layers has remarkably increased than the substrate. The wear performance of Nickel cladding has increased than Cobalt cladding and substrate sample, which reveals that Nickel-based laser cladding plays a role in wear resistance. The analyzed wear track indicates that adhesion and abrasion were the two major wear mechanisms.