Electroless Ni–P–TiO₂ Nanocomposite Coatings for Enhanced Durability and Saltwater Corrosion Protection of Jet Ski Engine Components

Jet ski engine components operate in aggressive marine environments where prolonged saltwater exposure
accelerates corrosion and mechanical degradation, leading to reduced service life and high maintenance costs. This study
investigates the development and performance of electroless (Nickel - Phosphorus - Titanium oxide) Ni–P–TiO₂
nanocomposite coatings as a protective surface modification for mild steel components. The coatings were produced using
an optimized electroless plating bath incorporating nano-sized TiO₂ particles into the Ni–P matrix to refine grain structure,
reduce porosity, and enhance passive film stability. Surface morphology and composition were examined using scanning
electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), while phase structure was analyzed via X-ray
diffraction (XRD). Mechanical performance was evaluated through microhardness testing, and corrosion resistance was
assessed using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 3.5 wt% % NaCl solution
to simulate saltwater exposure. The incorporation of TiO₂ nanoparticles produced a dense, uniform coating with improved
adhesion to the mild steel substrate. EIS measurements indicated significantly higher polarization resistance, confirming
superior long-term corrosion protection. These improvements are attributed to the barrier effect of well-dispersed TiO₂
nanoparticles, which impede chloride ion ingress and stabilize the passive layer. The results highlight that electroless Ni–P–
TiO₂ nanocomposite coatings present a cost-effective and high-performance strategy for extending the operational life of
mild steel jet ski engine components in harsh saltwater environments