Wear properties of self-lubricating Cr_xS_y/Ni coatings on 304 stainless steel by pre-placed laser cladding

Abstract

Self-lubricating NiCrBSi-Ni/MoS 2 coatings are prepared on 304 stainless steel by pre-placed laser cladding, in which Ni/MoS 2 is almost completely decomposed and the Cr x S y antifriction phase is in situ generated. Meanwhile, (Cr, Fe) 2 B and (Cr, Fe) 7 C 3 are generated from the molten pool as a result of oversaturated B and C atoms in γ-Ni and the diffusion of Fe atoms. Therefore, the composite coatings are mainly composed of γ-(Ni, Fe), (Cr, Fe) 2 B, (Cr, Fe) 7 C 3 , and Cr x S y . When compared with the substrate, the wear rate of the coatings with 20 wt-% Ni/MoS 2 is reduced by 21.16%, owing to the Cr x S y lubricating phase, while it is reduced by 25.61% for the coatings with 5 wt-% Ni/MoS 2 , owing to blocky (Cr, Fe) 2 B or (Cr, Fe) 7 C 3 hard phases. The wear mechanism of the coatings is adhesive wear and oxidative wear.

Advances in Laser-Clad, Particle-Reinforced Wear-Resistant Coatings: Enhancing Durability Through Material Innovation

“…Although the addition of Ti 3 SiC 2 can enhance the wear resistance of the coating, it also reduces the fluidity within the melt pool, causing the interfaces to become wavy and the highest hardness layer of the coating to shift downwards [86]. For cobalt-based coatings reinforced with Ti 3 SiC 2 , a 15 wt% addition provided the best wear resistance both at room temperature and at 600°C [87]. When Ti 3 SiC 2 reinforced Fe-based materials, the defect of Ti 3 SiC 2 inhibiting melt pool fluidity was amplified, causing the grains within the coating to grow coarser and the hardness to decrease, yet the coating's wear resistance was still improved through the formation of TiSi [88].…”