| Metal material are indispensable and important materials in human life,but they have been facing problems such as corrosion,wear and aging,and many protective measures have been developed to solve this problem.Thermal spraying technology can spray a coating on the surface of metal materials,play the role of wear-resistant and corrosion-resistant protective film,so it has a wide range of applications in surface protection of metal materials.High-speed arc spraying is a relatively efficient and convenient kind of thermal spraying.In this paper,three kinds of coatings were prepared on 45 steel substrate by high speed arc spraying.The microstructure,phase composition,hardness and tensile strength of the coating were analyzed by optical microscope,scanning electron microscope（SEM）,Spectrum analysis and energy spectrum analysis attached to the JXA-8230 electron probe microanalyzer,X-ray diffractometer（XRD）,microhardness tester and universal tensile tester.The pin-on-disk abrasive wear tester,electrochemical workstation and muffle furnace were used to characterize and analyze the friction and wear properties,electrochemical stability,high temperature oxidation resistance and thermal corrosion resistance of the matrix material and coating.The main conclusions are as follows:1)The cross-section of the three coatings are typical layered structure,which is mainly composed of metal particle phase,oxide phase and pores,and the bonding mode with the substrate is mainly mechanical bonding.The porosity of the three coatings is low,all below 10%.2)The surface hardness of the three coatings is about 2 to 3 times that of 45steel.Among them,the comprehensive mechanical properties of the ARC-1/ARC-2 coating are the best,the hardness of the surface is the highest,which is 45.79 HRC,and the tensile strength is also the highest,which is 40.67MPa.The wear resistance of the three coatings is higher than that of 45 steel substrate,and the friction wear of ARC-1/ARC-2 coating is the lowest,which is14.4mg,which is about 1/1.43 of 45 steel.3)The corrosion resistance of the three coatings is better than that of 45steel substrate.Electrochemical tests show that the self-corrosion potential of ARC-1/ARC-2 coating is the highest,the self-corrosion current density is lowest,and electrical chemical reaction resistance values is largest,which are-585.1m V,93.84μA·cm-2 and 7145Ω·cm2 respectively.In the high temperature properties of the sample,the high temperature oxidation weight gain and hot molten salt corrosion weight gain of ARC-2 coating were the lowest,which were 11.6mg/cm2 and 5 mg/cm2 respectively.The analysis shows that the coating has good corrosion resistance due to the dense oxides such as Al2O3 and Cr2O3 formed in the process of spraying and corrosion.4)When arc spraying adopts two kinds of wire materials with similar composition but not exactly the same,the coating prepared by this method has better comprehensive properties.It can not only solve the disadvantage of the large difference in melting point of two kinds of wires during heterogeneous twin-wire arc spraying,but also reduce the use of rare and precious metals,save cost and provide new ideas for heterogeneous twin-wire arc spraying.5)The three coatings were heat treated at 600℃for 2 h and sealed with LG-3 high temperature sealing agent.The surface structure of the coatings was observed and the comprehensive properties were tested.It was found that the hardness,wear resistance and corrosion resistance of the coatings were improved.Heat treatment and sealing treatment can change the physical structure of the coating and improve the compactness of the coating,thus enhancing comprehensive properties of the coating. |
