Study On Preparation And Tribological Properties Of Ni-CeO₂ Composite Coating Based On High-Velocity Oxygen-Fuel

Stainless steel materials have been widely used in the industrial field because of their good plasticity and corrosion resistance.However,under some complex working conditions,they have exposed their deficiencies in friction and wear resistance and corrosion resistance.The use of the high-velocity oxygen-fuel(HVOF)method to prepare protective coatings on stainless steel substrates,and to explore its friction,wear and corrosion resistance is of great significance to the protection of stainless steel materials.The Ni-based coating has good corrosion resistance and wear resistance,and the nano-CeO₂ particles can further improve the quality of the Ni-based coating.Therefore,this paper analyzes the flame behavior and the flight characteristics of Ni-based powder during the supersonic flame spraying process with the help of numerical simulation method,and prepares the Ni-CeO₂ composite coating under the optimized process parameters,and through friction,wear and electrochemistry In the experiment,the wear resistance and corrosion resistance of the composite coating were studied,and the details are as follows:Based on the method of computational fluid dynamics(CFD),Take the JP8000 spray gun as the research object,the optimal oxygen-to-oil ratio O/F=3 is obtained,and the flame flow characteristics are the best at this time;in order to explore the fluid-solid coupling characteristics of the fluid flame flow and the solid powder particles,the spray powder is analyzed The dynamic behavior of the particles in the flowing flame provides the relationship between the particle size and the physical state(melting temperature,impact velocity)of the particles when they are deposited.Numerical calculation results systematically show the influence of oxygen and oil flow parameters,powder incidence speed,particle size on the temperature,velocity and flight trajectory of solid particles.The CeO₂-Ni composite coatings obtained at different nano-CeO₂ ratios were prepared by the HVOF process.The surface characteristics of the coatings were analyzed through experimental methods.The experiments proved that the existence of nano-CeO₂ achieved a good modification effect,the porosity,hardness,and bonding area between the coating and the substrate of the Ni composite coating are better than those of the Ni-based coating without CeO₂added.When the addition amount is 1%,the Ni-based composite coating has the flattest morphology,showing the best coating surface characteristics.The friction and wear characteristics and mechanism of the composite coating were explored with the help of a friction and wear test machine;the corrosion law and mechanism of the composite coating were explored with the aid of an electrochemical workstation.Experiments show that the amount of wear decreases first and then increases with the increase of the proportion.The wear mechanism gradually changes from adhesive wear to abrasive wear.When the proportion is 1%,the friction coefficient of the Ni-CeO₂ composite coating and The wear amount is the smallest and the wear resistance is the best;the corrosion resistance shows a trend of first strengthening and then weakening with the increase of the proportion.When the proportion is 1%,the Ni-CeO₂ composite coating has the strongest corrosion resistance.In summary,when the proportion of nano-CeO₂ is 1%,the composite coating has the best tribological performance.