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首页> 外文学位 >In-situ Surface Enhanced Raman Spectroscopy Investigation of the Surface Films on Alloy 600 and Alloy 690 in Pressurized Water Reactor-Primary Water.
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In-situ Surface Enhanced Raman Spectroscopy Investigation of the Surface Films on Alloy 600 and Alloy 690 in Pressurized Water Reactor-Primary Water.

机译：原水表面增强拉曼光谱研究在压水反应堆-原水中的600和690合金表面膜。

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摘要

Alloy 600 is found to be susceptible to stress corrosion cracking (SCC) in Pressurized Water Reactor (PWR) primary water environment. In this study, in-situ Surface Enhanced Raman Spectroscopy (SERS) is used to characterize surface films formed on Alloy 600 and Alloy 690 in PWR PW at 320°C. A simulated PWR PW system is constructed. In addition, a titanium autoclave is designed for high-temperature electrochemical tests.;In this study, we have also measured SERS spectra of surface films formed on unalloyed nickel, unalloyed chromium, Ni-5Cr-8Fe, Ni-10Cr-8Fe, Ni-10Cr and Ni-20Cr. The surface films were formed at different potentials, from -0.9V to -0.5V vs SHE.;A formation of NiO film is observed on the surface of nickel at -0.65V, which shows a Raman peak at 540 cm-1 due to crystal defects. For pure chromium, Cr2O3 passive film is formed on its surface. The Raman peaks are located at 540 cm-1 and 610 cm -1. The thickness of Cr2O3 passive film is about several nanometers, depending on the growth time in PWR PW. A peak at 610 cm-1 would likely indicate Cr2O3 and the absence of this peak, in conjunction with a peak at 540 cm-1, would indicate NiO. It is found that the surface films on Ni-5Cr-8Fe and Ni-10Cr-8Fe alloys are composed of Cr2O3 and FeCr2O 4 spinel. No spinel oxide peak is observed in the SERS spectra for Ni-10Cr and Ni-20Cr binary alloys, and the surface film on both alloys is Cr 2O3. An analysis of SERS spectra indicate that, as alloy's chromium concentration increases, the amount of Cr2O3 included in the alloy's surface film would increase.;The surface film of Alloy 600 is composed of Cr2O3 inner layer (IL) and FeCr2O4 outer layer (OL). For short-time growth (10 min), the inner Cr2O3 layer is about 2 - 4 nm thick, and the average size of FeCr2O4 crystallites is about 10 nm. The actual film thickness depends on the growth time and aqueous environment. The surface film formed on Alloy 600 in PWR PW has a minor change if the sample is removed from the autoclave and exposed to air. The surface film of Alloy 690 is entirely a single layer of Cr2O3 (∼ 2 nm thick). According to Diffusion Path Analysis, the difference on surface films formed on Alloy 600 and Alloy 690 is a consequence of a change in the relative diffusivity of O and Cr. Our in-situ SERS spectra measured for surface films on Alloy 600 and Alloy 690 are different with most of other people's findings. Three aspects have been considered and discussed. The first, there might be a difference between in-situ and ex-situ characterization techniques. The second, the film growth time in PWR PW is significantly different. The third, different autoclaves are used. The recirculating titanium autoclave is used in this study, while stainless steel autoclave is used in most of other studies, which might cause a change of the concentration of cations in the vicinity of metal surface and a precipitation of cations on the surface of oxides. It is found that the exposure time and testing autoclave might be responsible for the discrepancies between this study and the earlier studies.;By using in-situ Surface Enhance Raman Spectroscopy (SERS), we have investigated the surface oxides formed on Alloy 600, Alloy 690, Ni-Cr, and Ni-Cr-Fe alloys in PWR primary water at 320°C. Our in-situ SERS spectra results suggest that SCC susceptibility of Ni-based alloys might be correlating with a formation of surface films formed in PWR primary water.
机译：已发现合金600在压水堆（PWR）的一级水环境中易受应力腐蚀开裂（SCC）的影响。在这项研究中，使用原位表面增强拉曼光谱（SERS）来表征在320°C的PWR PW中在600号合金和690号合金上形成的表面膜。构建了仿真的PWR PW系统。此外，还设计了用于高温电化学测试的钛高压釜。在这项研究中，我们还测量了在非合金镍，非合金铬，Ni-5Cr-8Fe，Ni-10Cr-8Fe，Ni上形成的表面膜的SERS光谱。 -10Cr和Ni-20Cr。表面膜是在相对于SHE的-0.9V至-0.5V的不同电势下形成的;在-0.65V的镍表面上观察到NiO膜的形成，由于540 cm-1处出现拉曼峰，原因是晶体缺陷。对于纯铬，在其表面上形成Cr2O3钝化膜。拉曼峰位于540 cm-1和610 cm -1处。 Cr2O3钝化膜的厚度约为几纳米，具体取决于PWR PW中的生长时间。 610 cm-1处的峰可能表示为Cr2O3，而该峰的缺失与540 cm-1处的峰一起表示为NiO。发现Ni-5Cr-8Fe和Ni-10Cr-8Fe合金的表面膜由Cr2O3和FeCr2O 4尖晶石组成。在Ni-10Cr和Ni-20Cr二元合金的SERS光谱中未观察到尖晶石氧化物峰，并且两种合金的表面膜均为Cr 2O3。对SERS光谱的分析表明，随着合金中铬浓度的增加，合金表面膜中所含Cr2O3的含量也会增加。;合金600的表面膜由Cr2O3内层（IL）和FeCr2O4外层（OL）组成。对于短时生长（10分钟），内部Cr2O3层的厚度约为2-4 nm，FeCr2O4微晶的平均尺寸约为10 nm。实际的膜厚取决于生长时间和水性环境。如果将样品从高压釜中取出并暴露在空气中，则PWR PW合金600上形成的表面膜的变化很小。 690合金的表面膜完全是一层Cr2O3（约2 nm厚）。根据扩散路径分析，在600合金和690合金上形成的表面膜的差异是O和Cr相对扩散率变化的结果。我们在合金600和690合金表面膜上测量的原位SERS光谱与其他大多数人的发现不同。已经考虑和讨论了三个方面。首先，原位和异位表征技术可能有所不同。第二，PWR PW中的膜生长时间明显不同。第三，使用不同的高压釜。在这项研究中使用了循环钛高压釜，而在其他大多数研究中都使用了不锈钢高压釜，这可能会导致金属表面附近的阳离子浓度发生变化，并导致氧化物表面上的阳离子沉淀。发现暴露时间和测试高压釜可能是造成本研究与早期研究之间差异的原因。通过使用原位表面增强拉曼光谱（SERS），我们研究了合金600，合金上形成的表面氧化物在320°C的PWR初级水中使用690，Ni-Cr和Ni-Cr-Fe合金。我们的原位SERS光谱结果表明，Ni基合金的SCC敏感性可能与PWR初级水中形成的表面膜的形成有关。

著录项

  • 作者

    Wang, Feng.;

  • 作者单位

    University of California, Berkeley.;

  • 授予单位 University of California, Berkeley.;
  • 学科 Engineering Mining.;Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 185 p.
  • 总页数 185
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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