金属氧化膜对激光辐照效应的影响

Oxidation effect for laser irradiating the metal

激光与材料的能量耦合系数是研究激光与物质相互作用的基础。金属在空气中与激光相互作用时,其能量耦合系数远大于理论值。文中以金属铁为例,研究金属氧化膜对激光与材料的能量耦合系数的影响。利用温度场计算结果,结合铁在空气中的氧化规律,计算了激光辐照下氧化层厚度的增长及氧化放热的影响;利用多层膜反射理论,结合氧化层厚度变化,分析了氧化膜导致的激光吸收增强效应,并将计算结果与实验结果进行比较,结果符合很好,证明了模型的合理性。计算结果表明,激光辐照期间,氧化放热对温度场的贡献很小,就工程应用来说可以忽略,而氧化层带来的吸收增强效应影响较大,不能忽略,辐照一段时间后,激光耦合系数可以用氧化物的理论计算耦合率近似表征。

A research on the influence of oxidation on temperature field result, oxidation layer thickness and the laser irradiating iron was done. Based on the quantity of heat in the course of oxidation were computed. Besides, by using multilayer reflective theory, the laser energy coupling coefficient was got with the varying oxidation layer thickness, and the computed value was in line with the experiment result very well. The result indicates that the oxidation heat had little effect when laser irradiated the iron and it could be ignored in engineering application. But the laser energy coupling coefficient may be influenced clearly by the oxidation behavior.