表面铁氧化态的拉曼测量

铁材料腐蚀时产生的铁锈具有各种氧化态和晶体结构，如Fe2O3、Fe3O4和FeOOH，导致拉曼光谱的差异（图1）。由于锈蚀的类型取决于暴露环境，因此对锈蚀氧化态的分析可以阐明腐蚀的原因以及预防腐蚀的必要步骤。在本说明中，我们介绍了使用显微拉曼光谱仪分析铁材料表面氧化态的结果。Application Note170-AN-0021 Raman measurement ofsurface iron oxidation states2/3Application Note Raman measurement of surface iron oxidation state s Introduction Rust tha t occurs when iron materials corrode has various oxidation states and crystal structures， such as Fe，O，，Fe ，O，and FeOOH， resulting i n differences in Raman spectra (Figure 1). Since the type of rust that occurs depends on the exposure environment， analysis of the oxidation state of the rust can lead to elucidation of the causes of corrosion， and the necessary steps to prevent it. I n this note， we introduce the results of analysis of oxidation states on the surface of i ron materials using a micro Raman spectrometer. Figure 1. Ra m an sp ec tra o f iron o xid es an d h ydr oxid e s Keywords R aman s p ectr os cop y， Su r f ace S ca n Im ag i ng (SSI)， Ir o n o x ide， co r r osi o n Experimental Samples： Two samples* taken from different environments (indoor and outdoor) were analyzed. *Details of the enviro n ment in which the samplers were previously exposed， both i ndoors and outdoors at the time of sampling are unknown. Measurement procedure and results： 1. Point measurements for each rust sample Multiple spectra from different oxidation states such as a-Fe， and Fe， were obtained f rom samples collected i ndoors，with y-FeOOH being mos tl y detected from samples collected f rom outdoor samples (Figure 2). Figure 2. Re sults o f s amp l e s coll e c ted o u tdoors 2. Imaging measurement of samples collected indoors (evaluation of component distribution) Three different spectra were obtained. Here， the typical spectrum of each component was used as the reference spectrum (the spectra are shown in Figure 4)， and a chemical image was created us i ng the correlation (similarity) with the reference spectrum. Using a false-color map to create a chemical image， it is possible to visualize the component distribution tha t may be difficult to determine visually， which is thought useful for analyzing the cause of corrosion. Parameters for i maging and point measurement Since the su r face of rusted metal has a l ot of irregularities， Surface Scan Imaging (SSI) was used for i maging n measurement along the i rregularities. (Reference： Application Note 260-AN-0017). SSI has the ability to quickly image and map rough or uneven samples. Main Unit： NRS-5500 Raman Spectrometer Ex wavelength 532nm Data interval 2um Exposure time 15 seconds Accumulation 1time Objective lens 100x， long work distance for dark fieldobservation Figure 3.N RS -5500 Ra man Sp e c t romet e r 28600 Mary's Cour t ， E asto n， MD 21601US A T el ： (800) 333-5272 F ax： (410) 822-7526 A ppli c a tio n Lib r ary： jasc o i n c.com /appli c ati o ns Figure 4. M eas u r ement re sul t s o f sample col le cted in doo r s Results Using Raman spectroscopy i t is possible to analyze the oxid a tion state and crystal st r ucture of inorganic substances， such as rust . In addi t ion， SSl is a very effec t ive tool for imaging measurement of samples with an uneven surface suc h as r u st . Model Description P/N Remarks Main Unit NRS-5500 Raman Spectrometer 7119-J051A 532 nm laser 100 mW laser was used， buta standard 50 mW is also available. Options RXY-57 Automatic XYZ stage 6947-J478B SSI-457 Surface Scan Imaging 7118-J378A RHG5-600B500 600 gr/mm grating 6947-J293A RMIX57 MIX observation unit 7119-J255A For dark observation and MIXobservation LMPLFLN100xBD Objective lens for darkfield observation，x100，long work distance， forVis range 1052-0196 Choose the lens according tothe sample. "MIX observation is useful for colored samples. Note： this is a factory option， f ield upgrade is not possible. An objective lens for dark observation is also required. · Measurement time， approx.30 minutes.To avoid changing the rust condition， weaken the laser intensity and increase the exposure time， it takes a little longer for wide-range imaging. · I f the surface roughness is not significant ， the standard imaging function can be used instead of SSI. JASCO INC . A ppli c a tio n Lib r ary： jasc o i n c.com /appli c ati o ns