用高重频激光剥离——火花诱导击穿光谱分析铝合金样品

Analysis of Aluminum Alloy by High Repetition Rate Laser Ablation Spark-Induced Breakdown Spectroscopy

为了提高基于等离子体原子发射光谱元素分析技术的分析速度,在高重复频率的前提下建立了一套激光剥离—火花诱导击穿光谱元素分析系统并以铝合金为样品开展了光谱分析。实验以低脉冲能量的声光调Q固体激光脉冲剥离样品,并触发高压火花放电以增强等离子体辐射、提高光谱分析灵敏度。研究结果表明:在高重频火花放电的作用下,等离子体辐射的峰值强度和弛豫时间分别得到了增强和延长,信号的时间积分强度增强因子可以达到1~2个数量级,且更易于实现时间分辨的信号检测。对铝合金中微量铬元素分析的检出限可达~132ppm。该研究验证了高重频激光剥离—火花诱导击穿光谱用于分析固体样品元素的可行性,其技术有望在固体样品元素的快速分析中发挥一定的作用。该光谱技术能同时兼顾扫描成像的速度、空间分辨率和光谱分析灵敏度,并为固体样品的二维或者三维元素分布的高分辨快速扫描成像分析提供了一种很好的技术途径。

In order to improve the analytical speed of elements analysis with plasma atomic emission spectroscopy,an elements analysis system with laser-ablation spark-induced breakdown spectroscopy under high repetition rate was established and aluminum alloy was analyzed spectrally with this system.In experiment,acoustic-optical Q switched laser pulses with low pulse energies were used to ablate samples and trigger high-voltage spark discharge to enhance plasma emission and improve spectral analysis sensitivity.It was demonstrated that the peak intensity of the plasma and its time duration were enhanced and prolonged respectively under the action of high repetition rate spark discharge.The time-integrated signal intensity could be enhanced 1~2 orders and the signal was easier to be detected with time-resolved technique.The limit of detection of trace chromium reached 132 ppm while analyzing aluminum alloy with this technique.It is possible to apply high repetition rate laser-ablation spark-induced breakdown spectroscopy to elements analysis of solid samples.This technique has advantages of high scanning speed,high spatial resolution and high analysis sensitivity.It can be applied to fast scanning mapping of two-dimension or three-dimensions elements distribution of solid samples.