Research On And Modification Mechanism Of Fe-Al Coating Reaction By Thermal Spraying

Due to the development of economy,the wear and high temperature loss of steel is more and more serious,so for high temperature oxidation resistance and wear resistance of the steel has certain requirements.At present,surface treatment is the most commonly used for the protection of steel,and the thermal spraying coating is the most commonly used method of surface treatment.Arc spraying is one of the best methods of thermal spraying because it has the advantages of low cost,high efficiency and high safety.The aluminum coating has a individual high temperature oxidation resistance,Fe-Al inter metallic compound has high room temperature good high temperature strength,and high temperature oxidation resistance,corrosion resistance and abrasion resistance and are widely used in high temperature materials and wear resistance materials.Therefore,the preparation of Fe-Al inter metallic compounds by Al coating can meet the requirements of anti-wear of steel surface,which can greatly improve the service life of materials.The diffusion depth of Al in carbon steel determines the ability of coating to protect the material and the service life of coating.If the diffusion depth is deeper,the protective ability of the coating is stronger,and the service life is longer.So it is necessary to study the diffusion process and diffusion coefficient.The Al coating was prepared by arc spraying,use the heating diffusion method to form the Fe-Al inter metallic compound.Study the Al coating after the heat treatment and diffusion layer morphology,microstructure,phase composition,also tested the high temperature oxidation resistance,hardness of Al coating and micro hardness of diffusion layer.The results show: The coating thickness,the heating time and the heating temperature can promote the formation of the diffusion layer,Fe-Al phase diffusion coefficient is 2.5×10-11m2s-1 at 1000?,the hardness of the coating and the diffusion layer is remarkably improved.The Fe-Al coating was prepared by arc spraying,use the heating diffusion method to form the Fe-Al inter metallic compound.This paper observe the morphology and phase composition of the coatings,and test the high oxidation resistance of the composite coating,and micro hardness.The experimental results show that: use the heating diffusion method to dispose Fe-Al double wire coating,diffusion layer is not formed,when the coating heated to 800?,the main formation Fe Al,Fe Al₂,Fe₂Al₅,when the coating heated to 800 ?,the main formation Fe Al₂,Fe Al₃,Fe₂Al₅.The double wire coating is five times the hardness of the Al coating,after heat treatment,the high temperature oxidation resistance of double wire coating is excellent.