Trace Titanium in Ferroalloy Studied by the Laser Induced Breakdown Spectroscopy
JIA Hao-yue1, LI Chuang-liang1*, YIN Xu-mei1, ZHOU Rui1, QIU Xuan-bing1, YANG Wen1, LI Kun1, WANG Gao2*, WEI Ji-lin1
1. School of Applied Science, Taiyuan University of Science and Technology, Taiyuan 030024, China
2. Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
Abstract：The concentration of titanium element in the ferroalloys was measured by laser induced breakdown spectroscopy. The maximum spectral signals were observed at the output energy of pulse laser at 50 mJ and the delay at 1 μs. Under this circumstance, traditional calibration method (TCM) and internal standard method (ISM) with Fe Ⅰ 438.35 nm and Fe Ⅰ 427.12 nm lines were used to quantitatively analyze the Ti in iron alloy. The fitting correlation coefficients (r) of ISM were 0.997 8 and 0.993 9 for Fe Ⅰ 438.35 nm and Fe Ⅰ 427.12 nm respectively, higher than that of TCM (0.956 3). This paper presented a double-line average internal standard method and resulted in 0.998 4 for r. In the range of Ti concentration from 0.063% to 1.9%, the relative errors were 23.7% and 6.0% for the TCM and ISM respectively. However, the relative error was reduced to 3.9% by the double-line average internal standard method. In addition, the temperature of plasma Ti was 6 654.3 K and the electron density was 1.072×1022 cm-3 through calculating the obtaining lines of Ti at the laser energy of 50 mJ. Furthermore, the relationship between the laser energy and the plasma temperature was discussed in the paper.
Key words：Laser induced breakdown spectroscopy; Ferroalloy; Titanium element; Internal standard method; Local thermodynamic equilibrium
