原子能科学技术2024，Vol.58Issue(7)：1514-1522,9.DOI:10.7538/yzk.2023.youxian.0525
一回路注锌对镍基690合金管腐蚀及腐蚀产物释放的影响
Effect of Zinc Addition on Corrosion and Metal Release Behavior of Nickel-based Alloy 690 in PWR Primary Water
贺韶 1刘峰 1李玉龙 1夏润杰 2汪家梅 2张乐福2
作者信息
- 1. 中广核研究院有限公司,广东深圳 518000
- 2. 上海交通大学核科学与工程学院,上海 200240
- 折叠
摘要
Abstract
The effect of Zn addition on general corrosion and metal release behavior of alloy 690 were investigated in simulated pressurized water reactor(PWR)primary water with 0,10 and 40 ppb Zn additions.The corrosion rate and the metal release rate were calculated by weight loss method after 3000 h exposure.The surface and cross-sectional morphology,thickness and element distribution along the oxide film were analyzed by scanning electron microscope(SEM)and transmission electron microscope-energy disperse spectroscopy(TEM-EDS).The crystallographic structure of the outer and inner oxides was identified using atomic-resolution TEM imaging with fast Fourier transformation(FFT).The results indicate that the corrosion rate,metal release rate and oxide film thickness of alloy 690 all decreased with the increase in Zn concentrations.The addition of 10 ppb Zn results in an approximately 18%reduction in the average corrosion rate and 14%reduction in the metal release rate,which further decreases by about 35%with an increase in Zn concentration to 40 ppb.Meanwhile,the average thickness of oxide film of alloy 690 significantly decreases from 110 nm to 25 nm when the concentration of Zn is increased from 0 to 40 ppb.The microstructural analysis of the oxide film indicates that the oxide film of alloy 690 exhibits a three-layer structure in 40 ppb Zn addition condition.The outermost oxide film has less Zn and is primarily composed of(Zn,Ni)Fe2O4.The intermediate oxide film contains much more Zn with a structure of Zn(Cr,Fe)2O4.The innermost oxide film at the oxide/metal(O/M)interface is mainly composed of Cr2O3.In PWR primary water,the free energy required for the formation of spinel ZnCr2O4 is lower than that of FeCr2O4 and NiCr2O4,and ZnCr2O4 exhibits a much lower solubility compared to other spinel,which results in its greater stability within the oxidation film.Meanwhile the Zn2+promotes the denser Zn(Cr,Fe)2O4 outer and intermediate oxide film formation by filling the cation vacancies and replacing the Ni2+and Fe2+in spinel.In summary,the Zn addition can significantly enhance the stability and compactness of the oxide film on alloy 690,thereby retarding the outward diffusion of metal ions and inward diffusion of oxygen ions.Additionally,it reduces the oxygen partial pressure at the O/M interface,promoting the formation of an inner layer composed of Cr2O3.Consequently,this effectively suppresses corrosion and minimizes metal release from alloy 690 in PWR environments.关键词
注锌/镍基690合金/均匀腐蚀/TEMKey words
Zn addition/nickel-based alloy 690/general corrosion/TEM分类
能源科技引用本文复制引用
贺韶,刘峰,李玉龙,夏润杰,汪家梅,张乐福..一回路注锌对镍基690合金管腐蚀及腐蚀产物释放的影响[J].原子能科学技术,2024,58(7):1514-1522,9.
