1.1 本指南涵盖了在温度高达500℃时碳和石墨的热扩散率的测定 °C。它仅适用于易于制造的小型试样。热扩散率值在0.04范围内 厘米 2. /s到2.0 厘米 2. /s可通过本指南轻易测量；但是，由于第节中概述的原因 7. ，对于超出此范围的材料，本指南可能不适用。 1.2 单位-- 以国际单位制表示的数值应视为标准。本标准中不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《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====== 5.1 热扩散率是瞬态热流条件下的设计应用、安全操作温度的确定、过程控制和质量保证等目的所需的重要特性。 5.2 闪光法用于测量各种固体材料的热扩散率（α）值。这是特别有利的，因为样品几何形状简单，样品尺寸要求小，测量速度快，并且易于用单个设备处理在大温度范围内具有宽范围热扩散率值的材料。所涉及的短测量时间减少了由于暴露在高温环境中而造成的污染和样品性质变化的机会。 5.3 在许多情况下，热扩散率结果可以与比热值（C p )和密度（ρ），从关系式λ=αC中导出热导率（λ） p ρ。有关将热扩散率转换为热导率的指导，请参阅实践 C781 。 5.4 本指南中描述的这种测试方法可用于表征石墨的设计目的。 5.5 试验方法 E1461 是本指南中描述的该测试方法的更详细形式，适用于更广泛的材料、应用和温度范围。

1.1 This guide covers the determination of the thermal diffusivity of carbons and graphite at temperatures up to 500 °C. It is applicable only to small easily fabricated specimens. Thermal diffusivity values in the range from 0.04 cm 2 /s to 2.0 cm 2 /s are readily measurable by this guide; however, for the reason outlined in Section 7 , for materials outside this range this guide may not be applicable. 1.2 Units— The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.3 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. 1.4 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 ====== 5.1 Thermal diffusivity is an important property required for such purposes as design applications under transient heat flow conditions, determination of safe operating temperature, process control, and quality assurance. 5.2 The flash method is used to measure values of thermal diffusivity (α) of a wide range of solid materials. It is particularly advantageous because of the simple specimen geometry, small specimen size requirements, rapidity of measurement, and ease of handling materials having a wide range of thermal diffusivity values over a large temperature range with a single apparatus. The short measurement times involved reduce the chances of contamination and change of specimen properties due to exposure to high temperature environments. 5.3 Thermal diffusivity results in many cases can be combined with values for specific heat (C p ) and density (ρ) to derive thermal conductivity (λ) from the relation λ = αC p ρ. For guidance on converting thermal diffusivity to thermal conductivity, refer to Practice C781 . 5.4 This test method described in this guide can be used to characterize graphite for design purposes. 5.5 Test Method E1461 is a more detailed form of this test method described in this guide and has applicability to much wider ranges of materials, applications, and temperatures.