氮气吸附静态容量法测定固体材料比表面积不确定度评定

Evaluation of the Uncertainty in the Measurement of Specific Surface Area of Solids by Nitrogen Adsorption Using Static Volumetric Method

氮气吸附静态容量法是测定固态材料比表面积最常用的方法,以吸附质和吸附剂发生多层物理吸附为基础,使用商用比表面积分析仪,依据标准GB/T 19587—2004《气体吸附BET法测定固态物质比表面积》测量了α-氧化铝的比表面积;详细分析了仪器测试过程中各个环节带来的不确定度分量,得出:不确定度主要来源于仪器校准、质量称量的重复性以及线性最小二乘法拟合数据,最后计算得到测量结果为(79.3±3.4)m^2/g(k=2)。

Nitrogen adsorption using static volumetric method was commonly used to determine the specific surface area of solids, it is based on the theory of muhimolecular layer physical adsorption. A case study was reported for evaluating the uncertainty of the measurement results, where a-A1203 was measured using commercial instrument in accordance with the standard GB/T 19587-2004, determination of the specific surface area of solids by gas adsorption using the BET method. The uncertainty was analyzed in detail in each process of the testing. The main uncertainty components were identified as calibrating instruments, repeatability of mass weighing and least square fitting of data. The measurement resuh is （79.3±3.4） m2/g （k=2）.