多孔材料表征方法的可靠性研究

Research on the Reliability of Characteristic Methods for Materials with Pores

从理论和实验两个方面讨论了物理吸附法和压汞法的理论依据、适用范围和影响因素.结果表明,N_2吸附法操作简单,样品可回收,通过不同的数学模型处理可以获得微孔(D<2 nm)和中孔数据.对于BJH法,最适宜的测量孔径D=2～100 nm,D>100 nm的孔径数据由于误差较大而可信度较低.适宜的脱气温度和脱气时间直接影响测量结果.压汞法最大的优势是用于大孔测量,最适宜的D=50～5000 nm,超过这一范围,则由于进汞压力测量误差增大而使孔径数据不可靠.压汞法的缺点是样品不能回收,操作时必须特别小心谨慎,防止汞中毒.

There are two popular methods for pore measuring, physical method with N2 and pressing mercury method. The basic theory,using range and affecting factors of the two methods were discussed in this paper. The research showed that physical method with N2 is good for its easier operation and its sample can be recycled. The finale data of miscropore to macropore can be obtained in the same time by using different mathematic models. However, the suitable range of diameter to measure is 2 to 100 nm, the data larger than 100 nm is less trustable. Besides, the sample predisposition is important for it affects the final results greatly. On the other hand, the advantages of pressing mercury method is macropore measuring and its suitable measuring range is 50 to 5 000 nm. Any data beyond this range will be less trustable. The shortcoming of pressing mercury method is that the sample can not be recycled and the operator must be very careful to prevent from being poisoned by the vapor of mercury.