Synergistic optimization of SiC concentration in Ni–SiC–WS2 hybrid coatings: Balancing tribology, mechanical properties, and corrosion resistance

One of the main challenges with composite coatings is achieving hardness and lubricity. Most existing studies on electrodeposited composites focus on binary systems: Ni–SiC, which enhances hardness but lacks self-lubrication, and Ni–WS 2 , which lowers friction but weakens mechanical strength. The combined incorporation of SiC and a solid lubricant (WS 2 ) introduce co-deposition challenges. This work addresses this gap by optimizing the ternary system to achieve high hardness and effective intrinsic lubricity. The goal of this study is to optimize the Ni-SiC-WS 2 hybrid coatings. The concentration of WS 2 is set at 3 g·L -1 , and the concentration of SiC is varied up to 10 g·L -1 . The optimal concentration of the coating is determined as a mixture of Ni, 3 g·L -1 WS 2 , and 5 g·L -1 SiC. The maximum micro-hardness is 1323±71 HV, representing a 253% improvement over pristine Ni. The coating also has the lowest coefficient of friction, 0.21, and the best corrosion resistance, with I corr = 3.9 ×10 -6 A·dm -2 . The improvement in the mechanical properties of the coating is quantitatively related to the Hall-Petch grain refinement and Orowan dispersion strengthening. The improvement in the corrosion resistance of the coating is due to a two-fold mechanism. Firstly, there is a geometric blocking mechanism, wherein inert nanoparticles block the passage of ions. Secondly, there is an enhanced repassivation of the matrix, facilitated by the grain boundaries. Increasing the concentration of 10 g·L -1 SiC results in catastrophic failure of the coating, due to extreme agglomeration and a critical concentration of lattice microstrain, exceeding 1%.