基于激光诱导击穿光谱的合金钢组分偏最小二乘法定量分析

在炼钢中合金浓度的检测和控制对产品质量影响很大，激光诱导击穿光谱(laser induced breakdown spectroscopy, LIBS)技术具有快速、非接触、无需制样等特点，非常适合应用于合金成分的在线分析。但是由于合金中的C, S, P元素的成分含量都很低，其原子发射谱线极易淹没在复杂的铁元素特征谱线之中，造成这些重要元素在线定量分析困难。以合金钢标准光谱样品为研究对象，获取激光诱导击穿光谱数据，采用定标曲线法(calibration curve, CC)和偏最小二乘法(partial least squares, PLS)，对合金钢样品的主量和微量元素进行定量分析。比较两种方法的定标结果得出：对于主量元素，PLS方法的定量分析水平优于传统的CC法;更重要的是对于微量元素，由于特征谱线极弱，CC法无法得出定量结果，而PLS法仍然具有良好的定量分析能力。同时，将PLS法回归模型特征谱线处的回归系数与原始有背景干扰的光谱强度数据进行比较，阐述了LIBS数据定量分析中PLS方法的优势。结果表明，在激光诱导击穿光谱合金成分分析中，PLS方法适合用于C等微量元素的定量分析。

Quantitative Analysis of Alloy Steel Based on Laser Induced Breakdown Spectroscopy with Partial Least Squares Method

In the present paper both the partial least squares (PLS) method and the calibration curve (CC) method are used to quantitatively analyze the laser induced breakdown spectroscopy data obtained from the standard alloy steel samples. Both the major and trace elements were quantitatively analyzed. By comparing the results of two different calibration methods some useful results were obtained: for major elements, the PLS method is better than the CC method in quantitative analysis; more importantly, for the trace elements, the CC method can not give the quantitative results due to the extremely weak characteristic spectral lines, but the PLS method still has a good ability of quantitative analysis. And the regression coefficient of PLS method is compared with the original spectral data with background interference to explain the advantage of the PLS method in the LIBS quantitative analysis. Results proved that the PLS method used in laser induced breakdown spectroscopy is suitable for quantitative analysis of trace elements such as C in the metallurgical industry.