本文件规定了小角X射线散射（SAXS）在测定比表面积中的应用。质量比表面积均为1？m2g-1到2？000？m2g-1和体积比表面积在0.01？m2cm-3比1？000？可以得到m2cm-3。 所描述的方法适用于稀释和浓缩系统。 注:？在ISO？17867:2020，通过SAXS测定粒度仅限于稀释系统。 仅对于两相系统，用SAXS确定表面是简单的。具有两个以上相的系统中的表面测定超出了本文档的范围。 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不仅测量开放孔隙的比表面积，还测量难以接近的封闭孔隙或夹杂物的比表面积。 注:？这与ISO中描述的气体吸附方法相反？9277:2010. 除了多孔系统之外，如果存在电子密度对比，内部界面可以对任何异质致密固体系统的测量比表面积做出贡献，例如在结晶相和无定形相之间。尽管包含微孔（孔宽？<？2？nm）的材料也可以用SAXS分析其比表面积，但本文档不涵盖这些材料。

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？m²g^-1 to 2？000？m²g^-1 and the volume specific surface areas in the range from 0,01？m²cm^-3 to 1？000？m²cm^-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.