高温高压水中镍和铬表面氧化膜的原位表面增强型拉曼光谱研究

In-situ Surface Enhanced Raman Spectroscopy Investigation of Surface Film Formed on Nickel and Chromium in High-temperature and High-pressure Water

摘要: 采用原位表面增强型拉曼光谱方法，研究了铬和镍在高温高压水中生成的表面氧化膜。镍氧化膜的拉曼光谱峰在540 cm^-1处，对应于NiO膜中形成的缺陷。电位小于-0.75 V时，弱540 cm^-1峰源于样品表面的残余氧化物。电位大于-0.7 V时，540 cm^-1峰较强，镍表面已生成稳定的NiO膜。铬氧化膜拉曼光谱有1个540 cm^-1强峰和1个610 cm^-1弱峰，对应于CrOOH或Cr₂O₃或两者的混合物。电位增大时，610 cm^-1峰强度减小，可能是因为氧化物从CrOOH转变成Cr₂O₃。本文的研究结果为Ni-Cr合金表面氧化物的判定提供了依据。

Abstract: In-situ surface enhanced Raman spectroscopy (SERS) was used to characterize surface films formed on Ni and Cr in high-temperature and high-pressure water. NiO shows a Raman peak at 540 cm^-1 due to crystal defects. Below -0.75 V, Ni-SERS has a very weak peak at 540 cm^-1, which is associated with air-formed oxide. Above -0.7 V, a stable NiO film is formed. Cr-SERS shows a strong peak at 540 cm^-1 and a weak peak at 610 cm^-1, which can be associated with a formation of CrOOH, or Cr₂O₃, or a mixture of two. The intensity of 610 cm^-1 peak decreases as the potential is raised and CrOOH is converted to Cr₂O₃. The identification on the surface films formed on Ni-Cr alloy in high-temperature and high-pressure water was discussed.