杨文迪,赵连红,沈明禄,崔中雨,何卫平,崔洪芝.A100超高强度钢激光熔覆CoCrNiNb0.1+B4C高熵合金涂层在模拟海洋环境下腐蚀行为研究[J].表面技术,2024,53(24):99-109.
YANG Wendi,ZHAO Lianhong,SHEN Minglu,CUI Zhongyu,HE Weiping,CUI Hongzhi.Corrosion Behavior of CoCrNiNb0.1+B4C High Entropy Alloy Coating on A100 Ultra-high Strength Steel by Laser Cladding under Simulated Marine Environment[J].Surface Technology,2024,53(24):99-109 |
| A100超高强度钢激光熔覆CoCrNiNb0.1+B4C高熵合金涂层在模拟海洋环境下腐蚀行为研究 |
| Corrosion Behavior of CoCrNiNb0.1+B4C High Entropy Alloy Coating on A100 Ultra-high Strength Steel by Laser Cladding under Simulated Marine Environment |
| 投稿时间：2024-01-18 修订日期：2024-03-09 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.24.009 |
| 中文关键词: CoCrNi基高熵合金涂层 激光熔覆 海洋腐蚀 |
| 英文关键词:Co-Cr-Ni based high entropy alloy coating laser cladding marine corrosion |
| 基金项目:中央高校基本科研业务费(202241012，202262011);山东省优秀青年基金(ZR2022YQ44) |
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| Author | Institution |
| YANG Wendi | School of Material Science and Engineering, Ocean University of China, Shandong Qingdao 266100, China |
| ZHAO Lianhong | China Special Aircraft Research Institute, Hubei Jingmen 448001, China |
| SHEN Minglu | School of Material Science and Engineering, Ocean University of China, Shandong Qingdao 266100, China |
| CUI Zhongyu | School of Material Science and Engineering, Ocean University of China, Shandong Qingdao 266100, China |
| HE Weiping | China Special Aircraft Research Institute, Hubei Jingmen 448001, China |
| CUI Hongzhi | School of Material Science and Engineering, Ocean University of China, Shandong Qingdao 266100, China |
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| 中文摘要: |
| 目的 探究B4C含量对A100超高强度钢激光熔覆CoCrNiNb0.1+B4C高熵合金涂层的显微组织、力学性能及其耐蚀性能的影响，阐明腐蚀机制。方法 探究合适的激光加工工艺参数，利用激光熔覆技术在A100钢基材表面制备了CoCrNiNb0.1+xB4C高熵合金涂层。通过SEM、EDS测试对涂层的显微组织和元素分布进行分析，通过XRD测试对涂层的物相组成进行分析。通过显微硬度测试对涂层的力学性能进行表征，通过电化学测试、浸泡实验对涂层耐蚀性能进行表征，并分析了涂层的腐蚀机制。结果 高熵合金涂层的显微组织均由树枝晶组成，其中，Cr、Nb、B、C元素富集在枝晶间区域，Co、Cr、Ni元素均匀分布。涂层的物相组成为基体FCC相和陶瓷相，陶瓷相Cr7C3、(Cr,Nb)23(C,B)6的含量随B4C含量的升高而升高。陶瓷相的出现形成了第二相强化效应，导致涂层显微硬度升高。随着B4C含量的升高，涂层的耐蚀性降低，表现为容抗弧减小、阻抗模值降低、过钝化电位降低。浸泡实验过程中，陶瓷相作为阴极相具有更高的电位，腐蚀反应的萌生位点为FCC相，两相间的电位差导致了电偶腐蚀的发生，电偶腐蚀为涂层主要的腐蚀失效机制。结论 B4C的加入导致涂层显微硬度提升、耐蚀性能降低。 |
| 英文摘要: |
| A100 ultra-high-strength steel is one of the ideal steel choices for the landing gear of amphibious aircraft. During actual service, it is often directly exposed to the marine environment, resulting in serious corrosion risks. Without affecting the mechanical properties of A100 ultra-high-strength steel, preparing a coating on its surface has become the first choice for surface protection. The high-entropy alloy coating prepared by laser cladding can achieve good protection on the surface of A100 ultra-high-strength steel. While ensuring the excellent mechanical properties and good corrosion resistance of the high-entropy alloy coating, it can achieve the metallurgical bonding of the coating and the substrate. Compared with traditional coatings and plating, the bonding strength is greatly improved. This paper designed high-entropy coating systems with different B4C contents to explore the effect of B4C content on the microstructure, mechanical properties and corrosion resistance of laser-clad CoCrNiNb0.1+B4C high-entropy alloy coatings on A100 ultra-high-strength steel, and elucidate the corrosion mechanism. This article explored the optimal laser processing process parameters, comprehensively considering the coating formability and performance, and finally determined the laser processing parameters as follows:laser power was 1.4 kW, scanning rate was 300 mm/min, and spot diameter was 3 mm. Heat-treated A100 ultra-high-strength steel with a size of 100 mm×15 mm×5 mm was selected as the base material, and different proportions (0%, 2%, 2.5%, 3%, 5% mass fraction) of B4C CoCrNiNb0.1 powder was used as coating raw material, and the coating was prepared after laser cladding. Then, the microstructure and element distribution of the coating were analyzed through SEM and EDS tests, and the phase composition of the coating was analyzed through XRD tests. The mechanical properties of the coating were characterized through microhardness testing, the corrosion resistance of the coating was characterized through electrochemical testing and immersion experiments, and the corrosion mechanism of the coating was analyzed. The results showed that the microstructure of the high-entropy alloy coating was composed of dendrites, in which Cr, Nb, B, and C elements were enriched in the interdendritic region, and Co, Cr, and Ni elements were evenly distributed. The physical phase composition of the coating was the matrix FCC phase and the ceramic phase. The contents of the ceramic phase Cr7C3, (Cr, Nb)23(C,B)6 increased with the increase of the B4C content. The emergence of the ceramic phase formed a second phase strengthening effect, which lead to an increase in the microhardness of the coating, with the highest hardness value reaching 1 090HV0.2. As the B4C content increased, the corrosion resistance of the coating decreased, which was manifested by a decrease in capacitive arc resistance, a decrease in impedance mode value, and a decrease in over-passivation potential. During the immersion experiment, the ceramic phase had a higher potential as the cathode phase, and the initiation site of the corrosion reaction was the FCC phase. The potential difference between the two phases lead to the occurrence of galvanic corrosion, which was the main corrosion failure mechanism of the coating. In conclusion, the addition of B4C leads to an increase in the microhardness of the coating and a decrease in corrosion resistance. |
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