Properties Research Of HVAS Fe-Al/Cr₃C₂ Composit Coatings

Compared to high velocity flame spraying techniques,high velocity arc spraying technology has such advantages such as:high spraying efficiency,energy-saving, cost-effective,better automatic and it could obtain good performance coating.by adjusting the powder of Fe-15Al/45Cr₃C₂,in the process of HVFS,six kind of different compound cored wires were obtained.In this present work,high velocity arc spraying (HVAS) cored wire technology was selected,the inter-metallic coatings with superior corrosion and wear resistance at high-temperature were also found,It is a good foundation for the industrial application of the coating in future.The adhesion strength,micro-hardness,corrosion and wear resistance at high temperature, erosion-wear resistance at high temperature and friction and wear behaviour of six Fe-Al/Cr₃C₂ composite coatings were investigated in this work.The morphology of coatings were observed by SEM and EDAX,its phase compositions were analyzed by XRD.The corrosion,erosion and the effect mechanism of rare earth oxidation on them were investigated.The main results of this work were summarized as follows:By microstructure analysis,it was found that the composite coating possessed typical laminate structure and the porosity,un-melted particles as well as large and flat size particles with small amount interface crack were existed in it,the particles bounded very well,a thin oxidation film existed between large and flat size layers and the reinforcement phase Cr₃C₂ distributed uniformly.The compound phases mainly included Fe,Al,Cr₃C₂,Fe₃Al/FeAl,FeCr as well as small amount Ce₂Ni₇.The adhesion strength of the three kind of coatings with the matrix were all more than 33MPa,the highest micro-hardness reached 444.32HV,as well as 44.02HRC.The composite coatings possess better property of hot corrosion resistance.The curve of corrosion dynamics follows the disciplinarian of parabola generally.The weight gains of the three composite coatings were about 67.25%,37.32% and 29.15% of the 20G substrate after 150h hot corrosion,and about74.6%,41.4%,32.3% of the Fe-15Al/45Cr₃C₂ composite coating of HVFS.The composite coatings can protect the substrate because of better erosion resistance.Because of the anomalous yield behavior of Fe-Al substrate,the erosion resistance decreases with the temperature increasing whether the erosion angle is 45°or 90°.The test results indicate that the composite coatings are provided with better colligation properties and lower cost which can satisfy the requirment of locale.So Fe-Al/Cr₃C₂ composite coating can be applied extensively.