Study Of Al₂O₃/FeSiB Composite Coating Prepared By Plasma Spraying

In this paper,Al₂O₃/Fe Si B composite coating was prepared by plasma spraying technology,and the preparation process of Fe Si B coating and Al₂O₃/Fe Si B composite coating was studied.The effect of Al₂O₃ content on wear resistance and corrosion resistance of Al₂O₃/Fe Si B composite coating was studied by adding Al₂O₃ceramic powder with different content.The results are as follows:（1）Al₂O₃/Fe Si B composite coating was successfully prepared by plasma spraying technology,and the structure was compact and no obvious defects existed.With the increase of spraying current,the ductility of Fe Si B and Al₂O₃ particles in the composite coating increases,porosity decreases,surface roughness decreases,and microhardness increases.When the spraying current is 650 A,the hardness of the coating is about 3 times of the base material,and the bonding strength is the best.Friction and wear experiments show that the composite coating has good wear resistance after adding Al₂O₃ ceramic,and the friction coefficient decreases gradually with the increase of spraying current.（2）Al₂O₃/Fe Si B composite coating was prepared by adding 5%,10%,15%and 20%Al₂O₃ to Fe Si B coating,respectively.Al₂O₃ phase is evenly distributed in the Fe base phase,and the surface roughness increases with the increase of Al₂O₃ content.When the Al₂O₃content is 20%,the hardness value is the highest and the bond strength is the best.（3）In 3.5%Na Cl solution,the self-corrosion potential becomes more and more positive with the increase of Al₂O₃ content.When Al₂O₃ content is 15%,the self-corrosion current is the minimum.In the friction and wear test,the friction coefficient decreases with the increase of Al₂O₃ content.The failure mode of coating changes from abrasive failure to coating shedding due to crack increase,and the wear mechanism changes from abrasive wear to fatigue wear.