电子探针分析钢表面氧化铁皮的状态

利用电子探针(EPMA)对标准样品及待测钢板分别进行了状态分析试验,结果表明:电子探针可有效判定钢表面氧化铁皮中Fe元素存在的不同价态,其中Fe元素L_β/L_α峰强比对照法最为实用,即通过电子探针测试获得待测试样的Fe元素Lβ/Lα峰强比,然后将该比值与标准样品的Fe元素Lβ/Lα峰强比进行对照,即可判断待测试样氧化铁皮层内不同位置铁的价态,从而鉴定物相为Fe₂O₃、Fe₃O₄、FeO或单质Fe。经多次测试,Fe₂O₃、Fe₃O₄、FeO、单质Fe 4种相的Fe元素Lβ/Lα峰强比分别为0.36、0.41、0.47、0.08,最大统计不确定度为0.02。依据Fe元素Lβ/Lα峰强比的差异,电子探针可对截面试样氧化铁皮的不同灰度区域进行物相鉴定,此外,还可对表面试样的氧化铁皮缺陷进行状态分析。

State analysis of oxide scale on steel plate surface by electron probe micro-analyzer

The state of standard sample and test steel plate was analyzed by electron probe micro-analyzer(EPMA). The results showed that EPMA could effectively evaluate the various valence states of Fe in oxide scale on steel surface. The comparison method of L_β/L_α peak intensity ratio of Fe element was the most practical. This ratio was compared with the L_β/L_α peak intensity ratio of Fe inreference materials, then,the state of Fe at various positions in oxide scale of test sample could be evaluated. Thus, the identified phases were Fe₂O₃, Fe₃O₄, FeO or pure Fe. After several tests, the L_β/L_α peak intensity ratio of Fe in Fe₂O₃, Fe₃O₄, FeO and pure Fe was 0.36, 0.41, 0.47 and 0.08, respectively. The maximum statistical uncertainty was 0.02. Based on the difference of L_β/L_α peak intensity ratio of Fe, the phase in various gray regions of scale in sectional sample could be identified by EPMA. Moreover, the state of oxide scale defect on sample surface could also be analyzed.