Study of corrosion and friction reduction of electroless Ni-P coating with molybdenum disulfide nanoparticles

One composite coating of Ni-P alloys containing MoS2 nanoparticles was prepared by electroless technique based on the better friction reduction ability of MoS2 and better anticorrosion property of electroless Ni-P alloys on carbon steel surfaces. Electrochemical method-that is, using Tafel polarization curves-was carried out in order to study the corrosion performance of the coating. The results indicate that the anticorrosion ability of the composite coating was decreased because of the addition of nano-MoS2 particles. The corrosional surfaces were studied and analyzed through scanning electron microscopy (SEM). The corrosion mechanism of the composite coatings was mainly ascribed to the formation of microcells around the nanosized MoS2 particles, and the active ion-like Cl- destroyed the surface film and induced the corrosion on the inside part of the coating. The friction coefficient of electroless composite coatings was measured by end-facing tribometer. It was found that the friction coefficient of the Ni-P-(nano-MoS2) composite coating decreased greatly compared with those of Ni-P electroless coatings.