摘要
目的采用异质双丝和同质双丝制备3种超音速电弧喷涂铁基涂层,对比研究3种防护涂层在700℃下的抗高温氧化性能。方法采用光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对在700℃高温氧化前后涂层的微观结构、表面形貌和化学成分以及物相组成进行表征和分析。采用Matlab软件对涂层的孔隙率进行测定,采用显微硬度计测量涂层的显微硬度。结果制备得到的3种涂层的孔隙率均低于10%,满足电弧喷涂的要求。3种涂层的显微硬度均达到了400HV以上,其中FeAlCrMoVC/FeAlNiMoCrC涂层的孔隙率最低、显微硬度最高,分别为5.00%和456.91HV。在700℃循环氧化下,FeAlCrMoVC、FeAlNiMoCrC和FeAlCrMoVC/FeAlNiMoCrC涂层的单位面积氧化增重分别为10.67、3.32和2.02mg/cm^(2)。它们的氧化动力学符合经典的抛物线规律,抛物线速率常数(kp)分别为3.08×10^(-10)、2.20×10^(-11)和5.60×10^(-12)g^(2)·cm^(-4)·s^(-1)。从高温氧化后涂层的扫描电镜图观察到,异质双丝法制备的涂层表面氧化膜主要由3种致密形貌组成,结合EDS和XRD分析,推断它们主要由Fe_(3)O_(4)、Fe_(2)O_(3)、Cr_(2)O_(3)和Al_(2)O_(3)以及尖晶石结构的NiCr_(2)O_(4)组成。截面分析发现,异质双丝制备的FeAlCrMoVC/FeAlNiMoCrC涂层的内氧化和表面氧化膜厚度最小,分别约为5.3、24.7和118.2μm。结论涂层的内氧化从孔隙和氧化夹杂物等缺陷开始,而生成的致密氧化物能够提高涂层的抗氧化性。超音速电弧喷涂制备的3种涂层都具有良好的抗高温氧化性能,而异质双丝法制备的FeAlMoCrC/FeAlNiMoCrVC涂层的抗高温氧化性能更好。
Because of its low cost,easy operation,and high deposition efficiency,supersonic arc spraying technology is extensively used in the field of preparation and repair of protective coatings.Hybrid twin-wire arc spraying technology is a process that employs two kinds of metal wires with distinct compositions to prepare composite coatings.Nonetheless,little research has been conducted on the high-temperature oxidation resistance of iron-based coatings made with the hybrid twin-wire method.The work aims to adopt two kinds of wire materials with similar but different components to solve the problem of the large difference in melting point of hybrid twin-wire arc spraying.Three kinds of ultrasonic arc-sprayed iron-based coatings were prepared on 45 steel substrates by hybrid and homogeneous twin-wires.The microstructure,surface morphology,chemical composition and phase composition of the coatings before and after high-temperature oxidation at 700℃were characterized by optical microscope(OM),scanning electron microscope(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD).The porosity of the coatings was measured by Matlab software,and the microhardness of the coatings was measured by a microhardness tester.The porosity of the three coatings was all lower than 10%,which could meet the requirements of arc spraying.The microhardness of the three coatings reached above 400HV,among which the hybird FeAlCrMoVC/FeAlNiMoCrC composite coating had the lowest porosity of 5.00%and the highest microhardness of 456.91HV.The high-temperature oxidation results showed that the mass gain/area of FeAlCrMoVC,FeAlNiMoCrC,and FeAlCrMoVC/FeAlNiMoCrC coatings reached 10.67,3.32 and 2.02 mg/cm^(2),respectively.Notably,the oxidation kinetics of the three coatings conformed to the classical parabolic law,and the parabolic rate constants(kp)were 3.08×10^(-10),2.20×10^(-11) and 5.60×10^(-12) g^(2)·cm^(-4)·s^(-1),respectively.According to the scanning electron microscopy(SEM)images after high-temperature oxidation,compared with
作者
任当精
唐旭
李雷
张一凡
江旭东
许征兵
曾建民
REN Dangjing;TANG Xu;LI Lei;ZHANG Yifan;JIANG Xudong;XU Zhengbing;ZENG Jianmin(State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,Nanning 530004,China;Key Laboratory of High-Performance Structural Materials and Thermo-Surface Processing,Education Department of Guangxi Zhuang Autonomous Region,Nanning 530004,China;Centre of Ecological Collaborative Innovation for Aluminum Industry in Guangxi,Nanning 530004,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第4期77-88,共12页
Surface Technology
基金
国家自然科学基金(51961008)
广西自然科学基金(2020GXNSFAA297269)。
关键词
异质双丝
超音速电弧喷涂
铁基涂层
动力学分析
抗高温氧化性能
hybrid twin-wires
supersonic arc spraying
Fe-based coatings
kinetics analysis
high-temperature oxidation resistance
