通过小角度X射线散射（SAXS）测定多孔和颗粒系统的比表面积

[中文适用范围]： 本文件详细说明了小角 X 射线散射 (SAXS) 在测定比表面积中的应用。 可以获得1 m2g-1 至2000 m2g-1 数量级的质量比表面积和0.01 m2cm-3 至1000 m2cm-3 范围内的体积比表面积。 所描述的方法适用于稀释和浓缩系统。 注：在 ISO 17867:2020 中，SAXS 测定粒径仅限于稀释系统。 仅对于两相系统，使用 SAXS 确定表面非常简单。 具有两个以上相的系统中的表面测定超出了本文件的范围。 术语“表面”是指不同密度（更准确地说：电子密度）的域之间的任何界面，并且不限于颗粒的外表面。 由于可以探测具有不同电子密度的区域之间的任何界面（不仅是空气或真空），因此该方法可以应用于任何异质系统。 SAXS 不仅可以测量开孔的比表面积，还可以测量难以接近的闭孔或夹杂物的比表面积。 注：这与 ISO 9277:2010 中描述的气体吸附方法相反。 除了多孔系统之外，只要存在电子密度对比，任何异质致密固体系统（例如结晶相和非晶相之间）的测量比表面积也可能受到内部界面的影响。 尽管也可以使用 SAXS 分析包含微孔（孔宽度 < 2 nm）的材料的比表面积，但本文件不涵盖这些材料。 [外文原描述]： This document specifies the application of small-angle X-ray scattering (SAXS) for the determination of specific surface area. Both the mass specific surface area in the order of 1 m 2 g -1 to 2 000 m 2 g -1 and the volume specific surface areas in the range from 0,01 m 2 cm -3 to 1 000 m 2 cm -3 can be obtained. The method described is applicable to dilute and concentrated systems. NOTE: In ISO 17867:2020, the determination of the particle size by SAXS is limited to dilute systems. The determination of surfaces with SAXS is straightforward for two-phase systems only. Surface determination in systems with more than two phases is beyond the scope of this document. The term ‘surface’ refers to any interface between domains of different density (more precisely: electron density) and is not restricted to the external surface of particles. As any interfaces between areas with different electron density, not only to air or vacuum, can be probed, the method can be applied to any heterogeneous system. SAXS measures not only the specific surface area of open pores but also of inaccessible, closed pores or inclusions. NOTE: This is in contrast to gas sorption methods which are described in ISO 9277:2010. In addition to porous systems, there can be contributions of internal interfaces to the measured specific surface area of any heterogeneous compact solid system, such as between crystalline and amorphous phases, provided there is an electron density contrast. Although materials comprising micropores (pore width < 2 nm) can also be analysed with respect to their specific surface area with SAXS, this document does not cover these materials.