Intergranular oxidation of Ni-based Alloy 600 in a simulated PWR primary water environment. (July 2016)

• Record Type: Journal Article
• Authors: Lim, Yun Soo; Kim, Sung Woo; Hwang, Seong Sik; Kim, Hong Pyo; Jang, Changheui
• Is Part Of: Corrosion science. Volume 108(2016)
• Page Start: 125
• Page End: 133
• Publication Date: 2016-07
• Subjects: A. Nickel -- A. Alloy -- B. STEM -- C. Internal oxidation -- C. Intergranular corrosion -- C. Selective oxidation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2016.02.040
• Languages: English
• ISSNs: 0010-938X

Abstract

Graphical abstract: Highlights: Intergranular oxidation is highly dependent on the grain boundary character. Nano-crystalline Cr2 O3 oxides form at the oxidized grain boundary. Ni elements are segregated as pure Ni nodules by the selective oxidation of Cr. Intergranular oxidation induces embrittlement of the grain boundaries. Abstract: Oxidation testing of Alloy 600 was conducted in PWR simulated primary water to obtain a clear understanding of intergranular cracking. The degree of intergranular oxidation was highly dependent on the grain boundary character. Random high-angle grain boundaries were deeply oxidized, and nano-crystalline Cr2 O3 oxides formed. However, oxygen diffusion was significantly suppressed on special boundaries. Metallic Ni was segregated as pure Ni nodules, indicating that the selective oxidation of Cr preferentially occurred. Intergranular oxidation and the resultant embrittlement of the grain boundaries are believed to be major factors affecting the occurrence of intergranular cracking in this alloy.