Research On Erosion-corrosion Properties Of Electrodeposition Process Alloy Plating

During the transportation of corrosive medium containing particles in pipelines,electrochemical reactions on metal walls and physical erosion caused by particle impact can generate wall thickness thinning and perforation,which will not only cause economic losses,but also pose potential safety hazards.Concerning the erosion and corrosion damage to underground pipeline columns in oil and gas fields,the paper selects N80 pipe steel as the matrix material,and electrodeposits Ni-W alloy coating and Ni-W/SiO₂ and Ni-W/TiO₂composite coating on its surface.Applying the testing methods of SEM,XRD,microhardness testing,electrochemical workstation,and liquid-solid erosion corrosion test bench,the influences of complexing agent concentration,plating solution temperature,current density,p H value of the plating solution,as well as the concentration of SiO₂ and TiO₂ nanoparticles on the microhardness,phase structure,surface morphology,corrosion resistance and erosion resistance of the alloy coating are explored.Combining the experimental results,the conclusions are drawn as follows:（1）The damage test results of Ni-W alloy coating and Ni-W/SiO₂and Ni-W/TiO₂composite coating on the surface of N80 steel show that the addition of SiO₂ and TiO₂nanoparticles refines the grain size of the Ni-W alloy coating and enhances the microhardness of the alloy coating.Influenced by the properties of the nanoparticles themselves,the Ni-W/SiO₂composite coating achieved a stronger effect on microhardness compared to the Ni-W/TiO₂composite coating.The microhardness increased by 1.4 times compared with the original matrix.（2）The test results of electrochemical corrosion resistance on Ni-W alloy coating and Ni-W/SiO₂and Ni-W/TiO₂ composite coating show that N80 steel with alloy coatings can effectively enhance the corrosion resistance of the substrate.When the concentrations of TiO₂and SiO₂ nanoparticles in the plating solution are 6 g/L and 10 g/L respectively,the Ni-W/TiO₂composite coating and Ni-W/SiO₂composite coating exhibit the strongest corrosion resistance.Especially,the Ni-W/TiO₂composite coating realized the most significant improvement in the corrosion resistance of the substrate,of which the self-corrosion current density decreased by73%compared to the substrate,and the impedance increased by 41 times compared to the substrate.（3）The test results of the anti-erosion damage of Ni-W alloy coating and Ni-W/SiO₂ and Ni-W/TiO₂ composite coating show that the anti-erosion performance of the coating is directly proportional to its microhardness when the high-speed fluid carries sand vertically on the surface of the coating.The surface erosion rate of N80 steel with the coating is about 2～5 times lower than that of the substrate,of which Ni-W/SiO₂ composite coating on the surface of N80 steel shows the optimal erosion resistance performance.