X射线荧光光谱法测定锌铁合金镀层铁含量的影响因素探讨

采用理学Simultix14型X射线荧光光谱仪测定锌铁合金镀层铁含量时,发现有部分试样的检测结果与国家标准推荐的方法存在较大差异,经验证,该设备不适用于低镀层量的试样和高强钢试样。实验从X射线荧光光谱仪(XRF)的检测原理、锌铁合金板的平整度、合金层结构、试样表面镀层均匀性、表面粗糙度及表面后处理等方面探讨了影响X射线荧光光谱法测定锌铁合金镀层铁含量准确性的原因。结果发现,实验用X射线荧光光谱仪的检测原理决定了该设备只适用于镀层质量大于40g/m²的试样;试样不平整时,检测结果偏大;试样的合金层结构(钢种)、镀层均匀性及表面粗糙度也会影响检测结果的准确性;而试样表面后处理(L处理)对检测结果无影响。该设备适用于镀层质量较大的平整的软钢试样。

Discussion on influencing factors during the determination of iron content in galvanized coating of zinc-iron alloy by X-ray fluorescence spectrometry

During the determination of iron content in galvanized coating of zinc-iron alloy by X-ray fluorescence spectrometry (Simultix 14, Rigaku), it was found that the measurement results of some samples had great difference with those obtained by recommended method in national standards. After verification, this instrument was not suitable for the sample with low coating content and high-strength steel. The factors influencing the determination accuracy of iron content in coating of zinc-iron alloy by X-ray fluorescence spectrometry (XRF) were discussed, including the detection principle of XRF, the flatness of zinc-iron alloy sheet, the structure of alloy layer, the uniformity of coating on sample surface, the surface roughness and post-treatment. The results showed that the detection principle of XRF decided that this instrument was only suitable for the sample with coating mass higher than 40g/m². When the sample was not flat, the measurement results would be higher. The structure of alloy layer (type of steel), the uniformity of coating and surface roughness would also influence on the accuracy of determination. However, the surface post-treatment of sample (L treatment) had no influence on the determination results. This instrument was suitable for the soft steel samples with high coating mass and good flatness.