熔融过程中升温和降温对Al特征谱线的影响

Effect of Heating and Cooling on the Characteristic Lines of Al During Melting

为了解决LIBS技术应用于冶金过程成分分析时,温度变化导致测量精度低,重复性差的问题,就温度变化对等离子体的影响进行研究。以Al元素为研究对象,对比分析不同温度下的光谱强度、等离子体电子温度和电子密度,总结了温度上升和下降时光谱强度和等离子体特征参数的变化规律。结果表明,Al元素特征谱线强度随温度上升呈增大趋势,在700℃时达到饱和,等离子体特征参数变化趋势与谱线强度基本一致,当样品温度加热至700℃时,等离子体电子温度上升至13122 K,电子密度增大至4.65×10^(16)cm^(-3);与温度上升相比,温度下降过程中,等离子体光谱强度,电子温度和电子密度的变化总体分为三个阶段。第一阶段,样品停止加热自然冷却,光谱强度、电子温度和电子密度随样品温度迅速下降;第二阶段,当样品温度下降至660℃左右时,光谱强度下降速度变缓,并趋于平稳,此时等离子体电子温度稳定在16000 K左右,电子密度为7.6×10^(16)cm^(-3);第三阶段,光谱强度及等离子体特征参数持续下降,直至样品温度下降至室温。由此可见,将LIBS技术应用于熔融金属成分检测时,可以通过控制样品温度,获取最佳的测量点,进而提高LIBS技术的检测准确性。

In order to solve the problem of low accuracy and poor repeatability caused by temperature change when LIBS technology is applied to the analysis of metallurgical process composition,the influence of temperature change on plasma is studied in this paper.The results show that the intensity of the characteristic lines of Al increases with the increase of temperature and reaches saturation at 700℃.When the temperature rises to 700,500 and 200℃,Al I increases When the sample temperature is 700℃,the plasma electron temperature rises to 13122 K,and the electron density increases to 4.65×10^(16)cm^(-3)respectively.In the first stage,the sample stops heating and naturally cools down,and the plasma parameters drop rapidly with the sample temperature;in the second stage,when the sample temperature drops to about 660℃,the spectral intensity decreases slowly and becomes stable.At this time,the plasma electron The temperature was stable at about 16000 K,and the electron density was 7.6×10^(16)cm^(-3);in the third stage,the plasma characteristic parameters continued to decrease until the sample temperature dropped to room temperature.When LIBS technology is applied to the detection of molten metal components,the best measurement point can be obtained by controlling the sample temperature,there by improving the detection accuracy of LIBS technology.