火花放电原子发射光谱仪分析高含量硅时校准曲线的扩展与应用

火花放电原子发射光谱仪分析高含量Si(w(Si)≥3.0%)时,其元素含量已超出了校准曲线的线性范围,导致分析值偏低。实验通过增加中低合金钢、硅钢标准样品,完善并扩展了Si校准曲线,完成了共存元素的干扰校正,拓宽了Si元素的分析范围,质量分数上限由3.14%扩展至4.16%,线性相关系数达0.99965。校准曲线扩展后重新选择标准化样品进行漂移校正,校准曲线强度比由9.41扩展至11.01。对扩展含量段的两个样品(w(Si)≥3.0%)进行精密度考察,结果的相对标准偏差(RSD,n=10)为0.43%和0.50%;对比了8个不同Si含量的样品,发现完善、扩展后校准曲线的Si测定值与认定值更相符;同时统计过程控制(SPC)控制图处于受控状态。可见校准曲线经完善、扩展后可满足工艺过程控制和成品分析要求。

Extension and application of calibration curve for the analysis ofhigh content silicon by spark discharge atomic emission spectrometry

During the analysis of high content silicon [w(Si)≥3.0%] by spark discharge atomic emission spectrometer, the elemental content was beyond the linear range of calibration curve, leading to the lower determination results. The standard samples of middle-low alloy steel and silicon steel were added in experiments to improve and expand the calibration curve of silicon. The interference of coexisting elements was corrected. The analysis range of silicon was broadened. The upper limit of mass fraction increased from 3.14% to 4.16%, and the linear correlation coefficient was up to 0.99965. After extension of calibration curve, the standardization sample was reselected for the drift correction. The intensity ratio of calibration curve was expanded from 9.41 to 11.01. Two samples with expanded silicon content [w(Si)≥3.0%] were used for precision test. The relative standard deviation (RSD, n=10) was 0.43% and 0.50%, respectively. Eight samples with different silicon contents were compared. It was found that the determination results by expanded calibration curves were more consistent with the certified values. Meanwhile, the statistical process control (SPC) chart was within the controlled state. Therefore, the modified and expanded calibration curve could meet the process control and analysis requirements of products.