1.1 本试验方法推荐了一种标准程序，用于测量不同等级的核石墨和/或人造碳在空气中的氧化速率。按照此处推荐的标准程序，可以获得表征受试材料在标准条件下抗氧化性的动力学参数，这些参数可用于材料选择和鉴定，以及制造过程中的质量控制。 1.2 本试验方法涵盖了标准尺寸和形状的机加工试样每暴露标称几何表面积或每初始重量的氧化失重率，或两者兼而有之。该试验在石墨和人造碳的空气氧化速率受反应动力学限制的温度范围内有效。 1.3 该试验方法还提供了标准氧化温度（定义见 3.1.7 )，以及氧化反应的动力学参数，即表观活化能和pre的对数- Arrhenius方程中的指数因子。Arrhenius方程的动力学参数是根据在Arrhenius图（定义见 3.1.8 )是线性的，定义为“动力学”或“化学控制”氧化状态。对于典型的核级石墨材料，发现实际测试温度范围约为500℃ °C至550 °C高达700左右 °C至750 °C。 1.4 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户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。 1.6 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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法可用于在标准条件下测量各种等级的人造碳和石墨的氧化速率，并可用于质量控制目的。 5.2 本试验方法标准化了以下条件:石墨试样的尺寸和形状；将其放置在垂直炉中，气流向上；使用分析天平和秤下端口进行连续重量变化测量的方法；空气流速必须足够高，以确保在使用的最高温度下氧化不会缺氧；用于计算氧化速率的失重曲线上的初始点和终点。 5.3 该试验方法还提供了氧化反应的动力学参数（表观活化能和指数前因子的对数）和标准氧化温度。结果表征了温度对空气中氧化速率的影响，以及具有标准尺寸和形状的机加工碳或石墨试样在动力学或化学控制的氧化状态下的抗氧化性。 该信息有助于区分具有不同杂质水平、粒度、孔结构、石墨化程度或抗氧化处理或其组合的材料等级。 5.4 准确确定的动力学参数，如活化能和指数前因子的对数，可用于预测空气中的氧化速率，作为与本试验方法类似的条件下温度的函数。然而，在Arrhenius图呈线性的温度范围外（在氧化的动力学或化学控制范围外）对此类预测进行外推时应格外小心。在以下条件下( 1. )氧化速率由化学反应以外的机制控制（例如氧化剂气体的孔内扩散或边界传输），或( 2. )氧化剂供给速率不够大，无法防止高温下出现氧化剂不足的情况，使用本试验方法确定的动力学参数预测氧化速率会产生高估的结果。

1.1 This test method recommends a standard procedure for measuring oxidation rates in air of various grades of nuclear graphite and/or manufactured carbon. Following the standard procedure recommended here, one can obtain kinetic parameters that characterize the oxidation resistance in standard conditions of tested materials and that can be used to for materials selection and qualification, and for quality control purposes in the fabrication process. 1.2 This test method covers the rate of oxidative weight loss per exposed nominal geometric surface area, or per initial weight of machined test specimens of standard size and shape, or both. The test is valid in the temperature range where the rate of air oxidation of graphite and manufactured carbon is limited by reaction kinetics. 1.3 This test method also provides a standard oxidation temperature (as defined in 3.1.7 ), and the kinetic parameters of the oxidation reaction, namely the apparent activation energy and the logarithm of pre-exponential factor in Arrhenius equation. The kinetic parameters of Arrhenius equation are calculated from the temperature dependence of oxidation rates measured over the temperature range where Arrhenius plots (as defined in 3.1.8 ) are linear, which is defined as the “kinetic” or “chemical control” oxidation regime. For typical nuclear grade graphite materials it was found that the practical range of testing temperatures is from about 500 °C to 550 °C up to about 700 °C to 750 °C. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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. 1.6 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 This test method can be used to measure the rate of oxidation for various grades of manufactured carbon and graphite in standard conditions, and can be used for quality control purposes. 5.2 The following conditions are standardized in this test method: size and shape of the graphite specimens; their placement in the vertical furnace with upwards air flow; the method for continuous weight variation measurement using an analytical scale with under-the-scale port; the air flow rate, which must be high enough to ensure that oxidation is not oxygen-starved at the highest temperature used; the initial and final points on the weight loss curve used for calculation of oxidation rate. 5.3 This test method also provides kinetic parameters (apparent activation energy and logarithm of pre-exponential factor) for the oxidation reaction, and a standard oxidation temperature. The results characterize the effect of temperature on oxidation rates in air, and the oxidation resistance of machined carbon or graphite specimens with standard size and shape, in the kinetic, or chemically controlled, oxidation regime. This information is useful for discrimination between material grades with different impurity levels, grain size, pore structure, degree of graphitization, or antioxidation treatments, or a combination thereof. 5.4 Accurately determined kinetic parameters, like activation energy and logarithm of pre-exponential factor, can be used for prediction of oxidation rates in air as a function of temperature in conditions similar to those of this test method. However, extrapolation of such predictions outside the temperature range where Arrhenius plots are linear (outside the kinetic or chemically controlled regime of oxidation) should be made with extreme caution. In conditions where ( 1 ) oxidation rates become controlled by a mechanism other than chemical reactions (such as in-pore diffusion or boundary transport of the oxidant gas), or ( 2 ) the oxidant supply rate is not large enough to prevent oxidant starving conditions at high temperature, prediction of oxidation rates using kinetic parameters determined with this test method will produce overestimated results.