高纯石墨标样热扩散系数测定及优化

Measurement of thermal diffusivity of high purity graphite standard sample and it’s thickness optimization

为了选取合适的热扩散系数标测定标样,用热压烧结法制备了高纯石墨,利用激光闪射法测试了不同厚度石墨试样的热扩散系数,研究了石墨热扩散系数随厚度的变化规律,分析了产生这种变化的原因.结果表明:不同温度下的石墨热扩散系数均在试样厚度3 mm时最高。选用高纯石墨热做为热扩散系数标样时,试样的厚度应在3mm左右,这样才能使被测试样的测试结果更精确.

In order to select the suitable thermal diffusivity standard samples, high purity graphite was prepared by hot pressing sintering method. The thermal diffusivity of graphite samples with different thickness were measured by laser flash method at different temperatures. The variation of thermal diffusivity of graphite with thickness was studied and the reasons for these changes were analyzed in this paper. The results shows that the thermal diffusivity of graphite sample with 3mm thickness is the highest among the samples at different temperatures. When high purity graphite is chosen as the standard sample of thermal diffusivity,the thickness of the sample should be about 3 mm, so that the results of the tested samples will be more accurate.