Electrodeposited Composite Coatings Based on Ni Matrix Filled with Solid Lubricants: Impact of Processing Parameters on Tribological Properties and Scratch Resistance

Electrodeposited composite coatings are widely studied for their potential to improve surface properties such as wear resistance and friction reduction. This study investigates the effect of electrodeposition parameters on the structure, morphology, and tribological performance of three coatings: pure nickel (Ni), Ni–graphite (Ni-G), and Ni–MoS2 (Ni-MoS2). Three deposition conditions were selected based on a review of key electrochemical parameters commonly used in the literature. The coatings were analyzed in terms of morphological characteristics, friction and wear resistance. The findings reveal that higher current densities led to increased friction and wear in Ni coatings, while lower pH values promoted finer crystallite sizes and improved tribological behavior. Ni-G coatings exhibited larger cluster formations with reduced friction and wear, especially at low pH, whereas Ni-MoS2 coatings developed a stable cauliflower-like morphology at pH 2, but showed reduced adhesion and structural integrity at higher pH levels. Scratch resistance tests performed under optimal deposition conditions showed that Ni-G coatings provided the highest resistance to mechanical damage, while Ni-MoS2 coatings were more susceptible to microcracking and adhesion failure. These results underscore the importance of optimizing deposition parameters to tailor the microstructure and functional properties of composite coatings for enhanced tribological and mechanical performance.