1.1 本指南涵盖了碳和石墨的透气性和气体扩散率的测量。讨论了两种技术，静态平衡法和真空泄漏法，这是一种能够测量气体渗透率和气体扩散率的综合方法，真空泄漏法测量样品的气体渗透率。 1.2 所讨论的两种气体渗透性技术都假设层流通过样品的孔。出于分析的目的，假设所得气体渗透率由粘性流（压力驱动的气体流）和滑移（气体分子与孔壁的相互作用）组成。通常，滑移的贡献比粘性流的贡献小得多，但在低渗透流和具有非常细孔径的样品的情况下可能是显著的。1.3 讨论了平均压力高达50 kPa和差压在5 kPa至50 kPa范围内的真空泄漏法的气体渗透率测量。 1.4 讨论了在100 kPa的平均压力和0.01 kPa至0.15 kPa范围内的差压下静态平衡法的气体渗透率测量。在中详述的相同条件下，还讨论了静态平衡法的气体扩散系数测量 1.4 . 1.5 本指南基于在12 Ø × 20 mm和19 Ø × 55 mm之间的小试样上进行的实验，但测试方法可能适用于其他尺寸。如果需要测试该几何形状之外的样本，用户将需要进行测试以确认技术是否合适。粘性系数范围为0。5 × 10 -10 厘米 2 至200.0 × 10 -10 厘米 2 可以通过所讨论的测试方法容易地测量。在0.001至0.5范围内的气体扩散率比可通过静态平衡法容易地测量。本指南所依据的测量和分析已作为ASTM技术论文发表。 2 1.6 单位- 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 附注1: 本指南中使用的术语渗透率考虑了同时存在粘性和滑移分量的气流，导致单位为cm 2 s -1 用于与渗透率以cm为单位给出的源进行比较 2 ，读者应考虑粘性系数，B 0 ，因为当滑移贡献可以忽略不计或以其他方式考虑时，这些相当于达西渗透率。1.7 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ======意义和用途====== 6.1 气体渗透性和气体扩散系数是正确模拟和理解气体和多孔介质之间的相互作用所需的重要性质，例如热和辐解氧化，或通过-通过石墨的产品。 6.2 本指南中描述的测试方法可用于表征石墨和碳材料，用于设计目的和辐照后检查（PIE）。

1.1 This guide covers the measurement of gas permeability and gas diffusivity of carbons and graphite. Two techniques are discussed, the static equilibrium method, an integrated method capable of measuring both gas permeability and gas diffusivity, and the vacuum leak method, which measures the gas permeability of the specimen. 1.2 Both of the gas permeability techniques discussed assume laminar flow through the pores of the specimen. For the purposes of analysis, it is assumed that the resultant gas permeability consists of viscous flow (pressure driven gas flow) and slip (the interaction of gas molecules with the walls of the pores). Generally, the contribution from slip is much smaller than that from viscous flow but can be significant in cases of low permeable flow and specimens with very fine pore sizes. 1.3 Gas permeability measurements are discussed for the vacuum leak method at mean pressures up to 50 kPa and differential pressures in the range 5 kPa to 50 kPa. 1.4 Gas permeability measurements are discussed for the static equilibrium method at a mean pressure of 100 kPa and differential pressures in the range of 0.01 kPa to 0.15 kPa. Gas diffusivity measurements are also discussed for the static equilibrium method under the same conditions detailed in 1.4 . 1.5 This guide is based on experiments conducted on small specimens between 12Ø × 20 mm and 19Ø × 55 mm, but the test methods may be suitable for other sizes. Should the testing of specimens outside of this geometry be required, the user will need to undertake testing to confirm the techniques are suitable. Viscous coefficients in the range from 0.5 × 10 -10 cm 2 to 200.0 × 10 -10 cm 2 are readily measurable by the discussed test methods. Gas diffusivity ratios in the range of 0.001 to 0.5 are readily measurable by the static equilibrium method. The measurements and analysis from which this guide has been derived have been published as an ASTM technical paper. 2 1.6 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Note 1: The term permeability as used in this guide considers gas flow where both viscous and slip components are present, resulting in units of cm 2 s -1 . For comparison with sources where permeability is given in units of cm 2 , readers should consider the viscous coefficient, B 0 , as these are equivalent to the Darcian permeability when slip contributions are negligible or otherwise accounted for. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 6.1 Gas permeability and gas diffusivity are important properties required for correctly modeling and understanding interactions between gases and porous media, for example thermal and radiolytic oxidation, or the escape of gaseous fission by-products through graphite. 6.2 The test methods described in this guide can be used to characterize graphite and carbon materials for design purposes and post irradiation examination (PIE).