固态和液态钢的激光诱导等离子体比较

比较了产生于室温固态钢以及高温液态钢上激光诱导等离子体的特征、原子铁的激发温度以及电子密度。通过在386～400nm波长范围的中性铁原子发射谱线, 由波尔兹曼作图法确定了铁原子的激发温度。通过测量AlI394.4nm的谱线宽度, 估算了电子密度。对固体钢来说, 铁元素的激发温度从延迟时间为10μs时的10800K下降到延迟时间为80μs时的7300K。当延迟时间分别为10μs和70μs时, 产生于固态钢和液态钢上等离子体间的激发温度并没有显著差别。在铁元素和铝元素大部分的中性原子线中, 可以观察到液态钢的谱线宽度比固态钢的谱线宽度更窄。当激光脉冲的观察延迟时间均为10μs时, 产生于液态钢上等离子体的电子密度大约为(0.99±0.15)×10¹⁷/cm³, 这相当于产生在固态钢上等离子体电子密度的46%。

Comparison between the plasmas induced by laser on solid and molten steels

Plasma characteristics, excitation temperatures of atomic iron and electron densities, were compared between the laser-induced plasmas generated on solid steel at room temperature and molten steel. The excitation temperatures of iron atom were determined by Boltzmann plot using neutral iron atomic emission lines in the wavelength range of 386 to 400 nm. Electron densities were estimated by measured linewidths of AlⅠ394.4 nm. Excitation temperature of iron decreased from 10 800 K at 10 μs to 7 300 K at 80 μs of delays for solid steel. Excitation temperatures were not distinguishable between the plasmas generated on solid and molten steels at delays of 10 and 70 μs, respectively. The linewidths observed with molten steel were narrower than those observed with solid steel in most of neutral atomic lines of iron and aluminum. Electron density in the plasma produced on molten steel was estimated to be (0.99±0.15)×10¹⁷ cm^-3, which was 46% of electron density in the plasma on solid steel at the same observation delay of 10 μs from the laser pulse.