光学学报, 2019, 39 (1): 0114002, 网络出版: 2019-05-10
电磁搅拌辅助激光熔覆钴基合金涂层的抗热腐蚀性能 下载: 957次
Thermal Corrosion Resistance of Co-Based Alloy Coatings by Laser Cladding Assisted by Electromagnetic Stirring
激光技术 激光熔覆 电磁搅拌 钴基涂层 微观结构 热腐蚀 laser technique laser cladding electromagnetic stirring Co-based coating microstructure hot corrosion
摘要
在激光熔覆制备钴基合金涂层的过程中引入电磁搅拌,研究了有无磁场辅助时涂层表面在750 ℃/100 h混合盐条件下的抗热腐蚀性能。研究结果表明,无磁场辅助的涂层的抗热腐蚀性能较差,热腐蚀60 h后涂层内部出现严重的内氧化和内硫化,并出现严重失重现象。经磁场辅助的熔覆层形成了稳定性好的保护性Cr2O3及CoCr2O4尖晶石氧化膜,有效抑制了腐蚀液中S和Cl
-的向内侵入,在整个腐蚀阶段样品未出现严重开裂剥落现象。电磁搅拌的加入有效细化并均化了熔覆层的显微组织,促进了涂层表面保护性氧化膜的快速形成,阻止了熔盐的扩散,可进一步提高涂层的抗热腐蚀性能。
Abstract
Electromagnetic stirring technique is introduced into the processing of laser cladding for preparing Co-based alloy coatings. In this research, a detailed analysis of hot corrosion resistance is conducted for a cladding layer applied in a salt mixture at 750 ℃ for 100 h with and without the assistance of electromagnetic stirring. The cladding layer is found to have poor hot corrosion resistance without magnetic field assistance. After hot corrosion for 60 h, the inside of the coating shows severe internal oxidation and vulcanization as well as substantial weight loss. In contrast, electromagnetic stirring produces a cladding layer that effectively suppresses the inward intrusion of S and Cl
- ions in the etching solution. This suppression facilitates the formation of stable protective Cr2O3 and CoCr2O4 spinel oxide films so that only slight cracking and peeling occur during the entire hot corrosion stage. The addition of electromagnetic stirring effectively refines and homogenizes the microstructure of the coating, and also promotes the rapid formation of a protective oxide film on the coating surface, which can prevent the diffusion of molten salt; thus, the hot corrosion resistance of the coating can be further improved.
徐家乐, 周建忠, 谭文胜, 黄舒, 孟宪凯, 何文渊. 电磁搅拌辅助激光熔覆钴基合金涂层的抗热腐蚀性能[J]. 光学学报, 2019, 39(1): 0114002. Jiale Xu, Jianzhong Zhou, Wensheng Tan, Shu Huang, Xiankai Meng, Wenyuan He. Thermal Corrosion Resistance of Co-Based Alloy Coatings by Laser Cladding Assisted by Electromagnetic Stirring[J]. Acta Optica Sinica, 2019, 39(1): 0114002.