Study on Microstructure and Properties of Nickel-Based Self-Lubricating Coating by Laser Cladding

Abstract

Ni35 + 20% SiC + 20% Ni/MoS2 self-lubricating coatings were fabricated on a grade 45 steel surface by laser cladding to obtain better comprehensive performance of wear resistance and corrosion resistance. The macroscopic morphology, microstructure, microhardness, phase composition, corrosion resistance and wear resistance of the coatings were investigated. The results show that the microstructure of the cladding layer is dense, mainly composed of cellular crystal and equiaxed crystal; The average microhardness of the coating is about 700 HV; The phase composition of the coating mainly includes Ni-Cr-Fe solid solution and metal sulfide, such as MoS2, NiS, Cr2S3, and CrMo3S4; Under the simulated seawater environment of 3.5% NaCl, the self-corrosion potential is 0.052 V and the self-corrosion current density is 1.69 × 10−5 A∙cm2. Compared with grade 45 steel, the corrosion resistance is greatly improved; After 20 min of wear, the weight loss of the cladding layer is about 0.17 times that of the grade 45 steel, the friction coefficient is small, and the wear resistance is significantly improved.