文献类型：期刊文献

中文题名：激光熔覆 CoCrFeNi-（Mn，Al）高熵合金涂层的耐腐蚀性能研究

英文题名：Study on Corrosion Resistance of Laser-Clad CoCrFeNi-(Mn, Al) High-Entropy Alloy Coating

作者：Luo, Fangyan[1];Jin, Hongtao[1];Chen, Zehuan[1];Shi, Wenqing[2];Huang, Jiang[1,3]

机构：[1]Guangdong Ocean Univ, Sch Elect & Informat Engn, Zhanjiang 524088, Guangdong, Peoples R China;[2]Guangdong Ocean Univ, Sch Mat Sci & Engn, Yangjiang 529500, Guangdong, Peoples R China;[3]Guangdong Prov Key Lab Intelligent Equipment South, Zhanjiang 524088, Guangdong, Peoples R China

年份：2026

卷号：63

期号：7

外文期刊名：LASER & OPTOELECTRONICS PROGRESS

收录：EI(收录号：20261920660051)、ESCI(收录号：WOS:001758340100029)、WOS

语种：中文

外文关键词：high-entropy alloys; corrosion resistance; laser cladding

外文摘要：Objective In this study, CoCrFeNi, CoCrFeNi-Mn, and CoCrFeNiAl coatings were fabricated on Q235B steel using laser cladding technology. The microstructure, electrochemical corrosion behavior, and immersion corrosion performance in a simulated seawater environment of the commonly used CoCrFeNi-based high-entropy alloy (HEA) coatings were investigated. The composition of the passive films on the coatings was characterized by X-ray photoelectron spectroscopy (XPS). Moreover, the influence of different valence states of various metal elements on the properties of the passive films was discussed in detail. This work provides a theoretical basis and research directions for subsequent studies on the electrochemical corrosion and immersion behavior of CoCrFeNi-based HEA coatings, as well as for improving their corrosion resistance, thereby promoting the application of CoCrFeNi-based HEA coatings in marine engineering. Methods Powders were pre-placed on the substrate surface using a standard mold with a thickness of (2 +/- 0.1) mm. Subsequently, coatings were fabricated using an XL-F2000 W fiber laser processing system. Based on preliminary experiments, the laser parameters were set as follows: laser power of 1200 W, scanning speed of 500 mm/min, defocus distance of +5 mm, spot diameter of 2.5 mm, overlap rate of 50 degrees o, number of melting tracks of 17, and melting length of 45 mm. Argon gas with a flow rate of 5 L/min was used as the shielding gas, starting 20 minutes before the experiment until its completion. The microstructure and elemental distribution of the coatings were characterized. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were employed to observe the morphology of immersed samples and analyze their elemental distribution. High-resolution X-ray diffraction (XRD) was used to determine the phase structure of the coatings. Electron backscatter diffraction was applied to analyze grain orientation and phase composition. Electrochemical experiments were conducted using a conventional three-electrode system with an electrochemical workstation in a 3.5 degrees o NaCl solution at room temperature. Afterward, the corroded micro-morphology of the samples was examined by SEM and EDS. For simulating seawater corrosion, samples were immersed in a 3.5 degrees o NaCl solution at 17 degrees C until obvious corrosion signs appeared. The exposed corrosion area was 10 mm & times;10 mm, with the remaining area coated with phenolic resin. XRD tests were then performed under the same parameters. X-ray photoelectron spectroscopy was used to analyze the passive film characteristics of the immersed samples. Results and Discussions The results indicated that under the same preparation parameters, the CoCrFeNi-Al coating exhibited more cracks, which would affect its corrosion resistance performance. The CoCrFeNi coating and CoCrFeNi-Mn coating were composed of the FCC phase, while the CoCrFeNi-Al coating consisted of the BCC phase. The FCC phase showed better corrosion resistance compared to the BCC phase. In addition, compared with the CoCrFeNi-Mn coating, the grain orientation distribution ratio of the CoCrFeNi and CoCrFeNi-Al coatings increased in the {111} group. Grains with the (111) (111) orientation demonstrated a stronger tendency toward dynamic passivation. Results from electrochemical and immersion experiments revealed that the CoCrFeNi coating possessed the optimal corrosion resistance, while the CoCrFeNi-Al coating exhibited relatively poor corrosion resistance. Analysis of the passive film composition showed that the passive film of the CoCrFeNi coating contained more protective oxides. However, the passive film of the CoCrFeNi-Al coating contained more hydroxides, and the presence of Al reduced the content of Cr3+ in the passive film, which was the main reason for its inferior corrosion resistance. Conclusions In this study, CoCrFeNi, CoCrFeNi-Mn, and CoCrFeNi-Al high-entropy alloy (HEA) coatings were fabricated using laser cladding technology. The effects of Mn and Al elements on the microstructure, phase composition, and corrosion resistance of the coatings were investigated. Due to the addition of Al, the CoCrFeNi-Al coating generated a large number of cracks, which severely impaired its corrosion resistance. The CoCrFeNi and CoCrFeNi-Mn coatings consisted of a single face-centered cubic (FCC) phase, while the CoCrFeNi-Al coating was composed of a single body-centered cubic (BCC) phase. This indicates that the Mn element does not induce a phase transformation in the CoCrFeNi HEA. In contrast, the addition of Al enables the CoCrFeNi HEA to undergo a phase transition from the FCC phase to the BCC phase. Theoretically, the FCC phase exhibits better corrosion resistance than the BCC phase. Compared with the CoCrFeNi-Mn coating, the grain orientation distribution ratio of the CoCrFeNi and CoCrFeNi-Al coatings increased in the {111} group. Grains with the (111) (111) orientation dynamically show the strongest passivation tendency. Both electrochemical tests and immersion experiments demonstrated that the CoCrFeNi coating had superior corrosion resistance, whereas the CoCrFeNi-Al coating exhibited the poorest corrosion resistance. The passive film of the CoCrFeNi coating was more stable and provided stronger protection. The passive film of the CoCrFeNi-Mn coating was the most unstable with the weakest protective capability. Although the passive film of the CoCrFeNi-Al coating showed relatively good stability and protectiveness, its corrosion resistance was the worst due to the presence of cracks.