Monitoring the Diffusion Layer During Passive Film Breakdown on Alloy 800 with Digital Holography

• Published in: Acta metallurgica sinica : English letters 2015-09, Vol.28 (9), p.1170-1174
• Main Authors: Xia, Da-Hai, Luo, Jing-Li, Gao, Zhi-Ming, Yuan, Bo-Yu, Li, Liang, Wang, Chao
• Format: Article
• Language: English
• Subjects: 800合金; Alloys; Breakdown; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chloride; Chloride ions; Chlorides; Corrosion; Corrosion and Coatings; Corrosion effects; Diffusion layers; Digital imaging; Dissolution; Electrodes; Electrolytes; Ferrous alloys; Holography; Interfaces; Localized corrosion; Materials Science; Metal ions; Metallic Materials; Monitoring; Nanotechnology; Organometallic Chemistry; Phase distribution; Pitting (corrosion); Spectroscopy/Spectrometry; Superalloys; Thiosulfates; Tribology; 击穿过程; 扩散层; 技术监测; 数字全息; 破裂过程; 硫代硫酸钠; 钝化膜
• ISSN: 1006-7191; 2194-1289
• DOI: 10.1007/s40195-015-0309-6

The effects of chloride and thiosulfate ions on localized corrosion of alloy 800 are investigated through dynamical observation of the change in phase image of the diffusion layer during passive film breakdown using digital holography. The results indicate that solution chemistry has a significant effect on film breakdown and diffusion layer. The phase distribution changes at different applied potentials show that in the process of film breakdown, dissolution of metal ions from pitting is not remarkable in chloride-only solution, whereas dissolution of metal ions is significantly high in thiosulfate and chloride solution. Thiosulfate has a combined effect with chloride ions in passive film degradation.