Study On The Organization And Performance Of Fe-Al₂O₃Functionally Gradient Coating Prepared By Plasma Spraying

Material is one of the three leading industries in the21st century, is the backboneindustry of industrial and agricultural production indispensable and the foundation of thescientific progress, social development and national strength enhanced. Wear and corrosionare two main failure mode of the material, which cause huge economic losses. Metalmaterials have strong plasticity, toughness and process ability, but high temperature andcorrosion resistance are poor. Ceramic materials has high hardness, high temperatureresistant, corrosion resistance, wear resistance and other excellent properties, but thebrittleness is very high, under the action of stress, it is easy to produce the defects such asmicro crack, as the crack spreading brittleness eventually lead to the broken parts or evenrupture. So high brittleness as one of the main defects of ceramic materials，relative to themetal materials, ceramic materials with low fracture toughness will cause the wholecomprehensive performance decline. If we can seek a kind of new material to combinethese two kinds of material effectively, foster strengths and circumvent weaknesses, notonly has good capability of plastic modified metal materials and high temperature resistant,corrosion resistance, corrosion resistance, high hardness and other good performances ofceramic material, so that it can meet the use of material in different work environment,enlarge the using range of the material performance and prolong the service life of thematerial. Along with the deepening of the research on new materials, metal matrix ceramicmaterial has get more and more attention of people, adding ceramic coating on metalsurface is popular in this kind of new material research direction. The main problems in thestudy of this kind of material is that the two kinds of material physical parameters do notmatch, such as elastic modulus and thermal expansion, In the process of adding coatinglayer, there are certain interface between coating and substrate material, due to the bondstrength is not enough often occur in the process of coating crack and even thephenomenon of peeling off from the substrate in practical application, for multilayercoating, it is also exist this problem between coating and coating, shock and vibrationperformance is not ideal, so it can not achieves the desired purpose. Based on theproduction of this kind of phenomenon, material workers put forward the concept offunctionally gradient coating material and began to study functionally gradient material.In this paper use the Q235steel as substrate material, the hydroxyl and reduced iron powder Fe and-Al2O3powder as spraying materials. Use ZB-80plasma sprayingequipment, argon as carrier and protection gas, high purity hydrogen gas for time, usingnegative pressure dc discharge of axial compression argon arc plasma torch, not transferredarc discharge, synchronous send powder to prepare Fe-Al2O3functionally gradient coating.Plasma spraying can melt refractory and molten metal at the same time, by controlling therelative supply rate of two kinds of powder to set the blend ratio in advance. Use powder asthe coating material, with argon as a carrier and shielding gas, blow into the hightemperature plasma jet transfer the energy to the particles. Spraying powder carry by argonplasma arc heating into molten or partially molten state, get some energy and speed,impacting on Q235substrate then formed in coating.Using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray energyspectrum analyzer (EDS) and micro hardness meter, WE-10type universal testingmachine，reciprocating sliding wear testing machine, CS350electrochemical workstationand other testing equipments to study the coating microstructure, hardness, bondingstrength， wear resistance and corrosion resistance. Optimize the technological parametersof plasma spraying process.