Tribological Properties and Thermal Stability of Fe/TiO2-Reinforced Ni Base Composite Coatings Fabricated Using Pulse Electrodeposition

M142 aluminum alloy, commonly used in piston systems, exhibits inadequate performance under prolonged high-temperature and high-load conditions. This study developed a TiO 2 nanoparticle-reinforced Ni-Fe composite coating via electrodeposition to address this. The effect of FeSO 4 ·7H 2 O concentration on Ni-Fe coatings was first investigated. The results show that hardness increased with FeSO 4 ·7H 2 O concentration, while the wear rate initially decreased and then increased. Adding TiO 2 nanoparticles effectively mitigated the adverse effects of high Fe content, leading to a dense, homogeneous composite structure (NFT15). Compared to the NF25 coating, the TiO 2 -reinforced coating demonstrated a 19.5% increase in hardness, a 30% improvement in adhesion strength, and a 30.9% decrease in wear rate. It also exhibited superior thermal stability, maintaining structural integrity and showing a 41.7% hardness increase after thermal cycling. Finally, a multi-performance evaluation identified the composite coating with 15 g L −1 TiO 2 as possessing the optimal overall properties.