Preparation And Repair Technology Of Key Components In Injection Pump By Using Ultrasound Jet Electrodeposited Ni-SiC Nanocoatings

In recent years,polymer injection pump is one of the most important injection equipmentfor the three stages oil injection.As a kind of volumetric reciprocating piston pump,the injection pump can be move circularly to change the working volume in the cylinder,and achieve the purpose of conveying high pressure and high viscosity polymers.Because the injection pump has been running in high viscosity and strong acid working medium for a long time,it is easy to appear the corrosion,wear and break for metal breakable parts such as injection pump cylinder,plunger,inclined disks,crankshaft and so on.Therefore,the repairing technology and performance of the metal parts of the injection pump has become one of the key technical problems which need to be explored for the third oil recovery field.Jet electrodeposition is a special processing method for the formation of metal base composite coatings on the cathode surface by spraying a certain pressure electrolyte solution to the plating part at high speed through the bath circulation system,thus it makes the metal ions in the bath undergo electrochemical reaction.Because of its particularity in mass transfer mode,diffusion layer thickness and limit current density,jet electrodeposition technology has become one of the key research topics at home and abroad.The ultrasonic processing technology is introduced into the jet electrodeposition technology,which can not only stir and disperse the particles in the bath,refine the grains,but also clean the electrode and promote the continuous electrodeposition processing.SiC nanoparticles were embedded into nickel grains by ultrasonic jet electrodeposition,resulting in Ni-SiC nanocoatings.Then,the application of the coatings in the repairing field of metal breakable parts of the injection pump can significantly improve the surface performance of the injection pump.therefore,how to determine and optimize the repairing process parameters of the metal breakable parts of the injection pump is of great significance for the preparation of Ni-SiC nanocoatings with high hardness,high strength,good wear resistance and corrosion resistance.Ni-SiC nanocoatings were taken as the research object in this research,and produced on the surface of Q235 steel used in polymer injection pump by using ultrasonic jet electrodeposition method.The process parameters of ultrasonic jet electrodeposited Ni-SiC nanocoatings were optimized by orthogonal test method.The effects of different plating parameters on the SiC content,microhardness,wear and corrosion of the coatings were also discussed.The optimum plating parameters for the ultrasonic jet electrodeposited Ni-SiC nanocoatings were obtained as follows:SiC nanoparticle concentration 8 g/l,cathode current density 2.5 A/dm~2,pulse duty cycle 50%,ultrasonic power 200 W,nozzle outlet diameter 8 mm,nozzle contraction angle 30°,pole spacing 20 mm,injection pressure 8 k Pa,injection speed 1 m/s.SEM analysis showed that the surface of the Ni-SiC nanocoating prepared by electrodeposition method is uneven and there were some large raised particles.When the ultrasonic jet electrodeposition method was applied in this experiment(ultrasonic jet electrodeposition combination parameter was 2),the surface protruding structure of the Ni-SiC nanocoating basically disappeared,and the coating surface was relatively flat and tight.AFM analysis showed that on the surface of electrodeposited Ni-SiC nanocoating,the larger granular tissue appears under atomic force microscope in the micro region,and the uneven phenomenon of the coating surface is obvious.When the ultrasonic electrodeposition was used,the particle size on the Ni-SiC nanocoating became smaller,and the surface of the coating also had obvious uneven phenomenon.However,when the ultrasonic jet electrodeposition was adopted(ultrasonic jet electrodeposition combination parameter was 2),the particle size on the surface of the coating was significantly smaller and distributed uniformly on the surface of the coating.The TEM analysis showed that there are large SiC particles on the surface of the Ni-SiC nanocoating prepared by electrodeposition method,and the agglomeration of SiC nanoparticles was serious.While the size of SiC nanoparticles prepared by ultrasonic electrodeposition was obviously smaller and the agglomeration phenomenon was obviously reduced.Nevertheless,the SiC nanoparticle size was much smaller in the Ni-SiC nanocoating obtained by ultrasonic jet electrodeposition,and the average particle size was approximately 30?50 nm.Moreover,the average particle size of Ni and SiC in ultrasonic jet electrodeposited Ni-SiC nanocoating was 48.81 nm and 36.85 nm,respectively.