Study On The Structure And Properties Of Ni-W-P-TiO₂ Nanocomposite Coatings

Ni-W-P alloy coating is an alloy coating that is expected to replace the chromium coating.It has high strength,hardness,excellent wear resistance and corrosion resistance,and is widely used in daily life and industrial production.In order to further improve the performance of the Ni-W-P alloy coating,nanoparticles are added to the Ni-W-P alloy plating solution to make it evenly dispersed in the alloy coating during the deposition process.The composite coating obtained has the comprehensive properties of matrix metal and solid particles.In this paper,based on composite chemical deposition technology and composite electrodeposition technology,particle-reinforced Ni-W-P-TiO₂ nanocomposite coating and sol-enhanced Ni-W-P-TiO₂ nanocomposite coating were prepared.The influence of phase composition,micromorphology,hardness,wear resistance and corrosion resistance of Ni-W-P-TiO₂ nanocomposite coating was systematically studied.The conclusions are as follows:?Particle-reinforced electroless Ni-W-P-TiO₂ nanocomposite coating:Compared with pure Ni-WP alloy coating,the addition of 1g/L TiO₂ nanoparticles refined the grain of particle-reinforced Ni-W-P-TiO₂ nanocomposite coating,making the coating changes to amorphous state.The hardness of the coating was increased by 25%to 689HV,and the wear resistance and corrosion resistance were enhanced.However,excessive TiO₂ nanoparticles were seriously agglomerated,resulting in increased porosity of the particle-reinforced Ni-W-P-TiO₂ nanocomposite coating,loose coating,reduced hardness,poor wear and corrosion resistance.?Sol-enhanced electroless Ni-W-P-TiO₂ nanocomposite coating:Compared with pure Ni-W-P alloy coating,the addition of 5m L/L TiO₂ sol improved certain density and uniformity of sol-enhanced Ni-W-P-TiO₂ nanocomposite coating.The hardness of the coating was increased to 625HV,the increase was up to 3%,and the wear resistance and corrosion resistance were strengthened.Meanwhile,compared with the Ni-W-P-1g/L TiO₂nanocomposite coating with better performance,the hardness of the sol-reinforced Ni-WP-5m L/L TiO₂ nanocomposite coating was slightly lower,but the microscopic morphology was better,the wear resistance and the corrosion resistance was better.?Particle-reinforced electroplated Ni-W-P-TiO₂ nanocomposite coating:Compared with pure Ni-W-P alloy coating,the amorphization degree of particle-reinforced Ni-W-P-TiO₂ nanocomposite coating prepared by 1g/L TiO₂ nano-particle coating is deepened.The thickness was the largest,reaching 22.5?m,the hardness of the coating was increased by 26%to 635HV,and the wear resistance and corrosion resistance were improved.The agglomeration of excessive TiO₂ nanoparticles made the surface morphology of the particle-reinforced Ni-W-P-TiO₂ nanocomposite coating change significantly,the thickness of the coating decreased,and it behaved poor wear resistance and corrosion resistance.?Sol-enhanced electroplated Ni-W-P-TiO₂ nanocomposite coating:Compared with pure Ni-W-P alloy coating,the disorder degree of the amorphous structure of the sol-enhanced Ni-W-P-TiO₂ nanocomposite coating increased when the TiO₂ sol is 5m L/L,the flatness of the coating surface was improved to a certain extent.The hardness of the coating was increased by 10%to 588HV,and the wear resistance and corrosion resistance were improved.Meanwhile,the sol-enhanced Ni-W-P-5m L/L TiO₂ nanocomposite coating had better wear resistance and corrosion resistance than the particle-reinforced Ni-W-P-1g/L TiO₂nanocomposite coating with better performance.