应用激光闪光法测量薄膜材料的热扩散率

目的是将用于测量片状试样的热扩散率的激光闪光法推广至测量薄膜试样。应用 1 5纳秒脉冲 Nd:YAG激光及响应时间 0 .9微秒的 (Hg,Cd) Te红外探测器等建立了闪光法热扩散率测量系统 ,并应用此系统对微米量级厚度的不锈钢薄膜进行了测量。同时针对将激光闪光法应用于薄膜时所出现的问题 ,如激光的有限脉冲时间及有限吸收厚度效应 ,测量系统的滞后效应 ,以及增强红外吸收及辐射用表面黑化膜的影响进行了分析并提出了解决方法

Measuring Thermal Diffusivity of Thin Film by Laser Flash Method

The laser flash method has become a widely accepted method for measuring thermal diffusivities of various materials over a wide range of temperatures.Restricted by heating and detecting techniques,however,this method was only used for plate-like specimens with the thickness of millimeters.When the laser flash method is employed to measure thin materials,some effects,which may be ignored for thick ones,should become important because of the limitation of the measuring systems.In this work,an attempt is made to extend the laser flash method to thin films with thickness of microns and to investigate the effects of pulse-width of the heating laser,the response lag of the measuring system,and the absorptive coating layer on thermal diffusivity measurements of thin materials.Then some approaches are given for minimizing these effects to get precise measuring results.