高速电弧喷涂Fe_3Al/WC复合涂层高温冲蚀行为研究

Erosion Behavior of Fe3Al/WC Intermetallic Matrix Composite Coating Produced By High Velocity Arc spray at Elevated Temperature

采用自行研制的新型热喷涂Fe3Al/WC复合合金粉芯丝材，成功地用高速电弧喷技术制备出了Fe3Al金属化合物基金属陶瓷复合涂层。对涂层成分、显微组织、涂层相结构和组成进行了分析，结果表明，涂层由以Fe-26Al为主的Fe3Al基体相与约20%的WC、W2C和 a-Al2O3相组成。对比研究了Fe3Al/WC涂层和电站锅炉钢20 g从室温至650 ℃氧化环境条件下不同攻角的高温冲蚀磨损性能，结果表明Fe3Al/WC涂层的高温冲蚀磨损抗力高于20 g钢，650 ℃和30°攻角下的稳态相对冲蚀磨损抗力为20 g钢的3.14倍。温度对Fe3Al/WC涂层的冲蚀行为有较大影响：温度 < 450℃，涂层的冲蚀率变化不大，表现出塑性材料的冲蚀行为；温度 >450 ℃，涂层冲蚀率变化较大，呈现典型的脆性材料冲蚀磨损行为。并对其高温冲蚀磨损机理进行了分析。

A novel cored wire for producing Fe3Al/WC intermetallic matrix composite (IMC) coating by thermal spraying was developed. High velocity arc wire spray technology was successfully applied to prepare the Fe3Al/WC IMC coating. The coating composition, microstructure and phases were investigated by energy dispersive X-ray (EDX), X-ray diffraction (XRD), scanning electron microscope (SEM) and image analyzer. Results show that the cored wire arc sprayed iron aluminide IMC coating consists of major phases of Fe3Al (Fe-26Al) and the reinforced hard phases of about 20%WC,W2C and a-Al2O3. As compared with boiler tube steel, the solid particles erosion-corrosion behavior under different incidence angles and test temperatures of Fe3Al/WC IMC coatings were determined. Results indicate that the erosion-corrosion resistance at elevated temperature of Fe3Al/WC IMC coating is higher than that of 20g steel. Under oblique impact condition, the relative erosion-corrosion resistance of Fe3Al is 3.14 times than that of 20g steel at temperature of 650℃. It seems that test temperature has great effect on the solid particle erosion behavior of Fe3Al/WC IMC coating. It is found that the Fe3Al/WC coating exhibits typical erosion behavior of ductile materials as increasing test temperature prior to 450℃. With increasing temperature beyond 450℃,the Fe3Al/WC IMC coating turns to exhibit the erosion behavior of brittle material. The erosion-corrosion mechanisms of Fe3Al/WC IMC coatings under elevated temperature were discussed.