激光诱导击穿光谱(LIBS)技术是应用于冶金在线分析最具前景的技术之一。 为了研究真空和高温条件下LIBS光谱特性和物质成分定量分析方法, 设计并搭建了可实现真空环境高温熔融金属LIBS光谱测量的实验系统。 系统以调Q Nd:YAG脉冲激光器为光源, 采用不同焦距透镜实现激光聚焦和信号光采集, 并利用光谱仪进行光谱检测, 真空获取和高温加热通过真空泵和中频感应电炉实现, 感应加热线圈通过陶瓷封接引线法兰与真空系统进行整合。 经过安装测试, 搭建系统在未加热情况下真空度可达1×10－4Pa, 加热温度可达到1 600 ℃, 可实现真空环境下铁、 铝等金属加热或熔融, 并获得相应环境下的LIBS测量光谱。 利用该系统进行真空和熔融条件下标准钢样品的LIBS实验, 得到了固态钢样品LIBS光谱在不同真空度下的光谱对比, 以及真空环境熔融态和固态钢样品光谱对比。 通过对测得的LIBS光谱进行数据处理和理论分析, 所得初步实验结果与现有研究结论相符合, 表明该系统工作状况良好, 可满足真空环境下的熔融金属成分分析研究的基本需求。

Laser-induced breakdown spectroscopy (LIBS) is one of the most promising technologies to be applied to metallurgical composition online monitoring in these days. In order to study the spectral characters of LIBS spectrum and to investigate the quantitative analysis method of material composition under vacuum and high temperature environment, a LIBS measurement system was designed and set up which can be used for conducting experiments with high-temperature or molten samples in different vacuum environment. The system co nsists of a Q-switched Nd∶YAG laser used as the light source, lens with different focus lengths used for laser focusing and spectrum signal collecting, a spectrometer used for detecting the signal of LIBS spectrums, and a vacuum system for holding and heating the samples while supplying a vacuum environment. The vacuum was achieved and maintained by a vacuum pump and an electric induction furnace was used for heating the system. The induction coil was integrated to the vacuum system by attaching to a ceramic sealing flange. The system was installed and testified, and the results indicate that the vacuum of the system can reach 1×10－4Pa without heating, while the heating temperature could be about 1 600 ℃, the system can be used for melting metal samples such as steel and aluminum and get the LIBS spectrum of the samples at the same time. Utilizing this system, LIBS experiments were conducted using standard steel samples under different vacuum or high-temperature conditions. Results of comparison between LIBS spectrums of solid steel samples under different vacuum were achieved, and so are the spectrums of molten and solid steel samples under vacuum environment. Through data processing and theoretical analyzing of these spectrums, the initial results of those experiments are in good agreement with the results that are presently reported, which indicates that the whole system functions well and is available for molten metal LIBS experiment under vacuum environment.