Nanoparticle-Reinforced Electroless Composite Coatings for Pipeline Steel: Synthesis and Characterization

Area of Science:

• Materials Science
• Surface Engineering
• Tribology

Background:

• Protective coatings are crucial for extending the lifespan of industrial components like oil and gas pipelines.
• Wear and corrosion are persistent challenges in these harsh operating environments.
• API X60 steel is a widely used high-strength carbon steel in pipeline infrastructure.

Purpose of the Study:

• To develop and characterize nano-sized TiO2-reinforced electroless nickel-based ternary (Ni-W-P) alloy and composite coatings.
• To evaluate the impact of TiO2 nanoparticles on coating properties and tribological performance.
• To investigate the effect of annealing on the microstructure and wear resistance of the developed coatings.

Main Methods:

• Electroless plating in an alkaline hypophosphite-reduced bath.
• Coating characterization using optical microscopy, FESEM, EDS, XRD, AFM, and 3D profilometry.
• Tribological testing including Vickers microhardness and reciprocating wear tests.

Main Results:

• The TiO2 nanoparticle-reinforced composite coating achieved ~24 µm thickness with enhanced microhardness and reduced coefficient of friction (COF).
• Annealing at 400 °C significantly improved tribological properties due to grain growth, phase transformation, and Ni3P crystallization.
• XRD confirmed a phase evolution from amorphous to crystalline Ni3P upon annealing, enhancing wear resistance.

Conclusions:

• The developed Ni-W-P composite coatings with TiO2 nanoparticles offer superior wear resistance and hardness.
• Annealing further boosts tribological performance, making these coatings suitable for high-wear applications in the oil and gas industry.
• Excellent adhesion was observed for both alloy and composite coatings.