1.1 本试验方法涵盖了伏安法测定新的或在用非锌汽轮机油中的受阻酚抗氧化剂，其浓度为0.0075 % 通过在产生的伏安图中的指定电压下测量电流量，以重量计，达到新油中发现的浓度。 1.2 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。 1.3 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。 1.4 本国际标准是根据世界贸易组织发布的《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 新汽轮机油中受阻酚抗氧化剂的定量测定测量了添加到油中作为抗氧化保护的这种材料的量。除酚类外，汽轮机油还可以与其他抗氧化剂（如胺）混合，以延长机油寿命。在用过的油中，该测定方法测量氧化降低其初始浓度后残留的原始（酚类）抗氧化剂的量。本试验方法的设计或目的不是检测在油的热应力和氧化应力过程中形成的所有抗氧化中间物，这些中间物被认为对已用或在用油的剩余使用寿命有一定贡献。它也不能衡量石油的整体稳定性，而这是由所有物种的总贡献决定的。在对使用过的机油的剩余使用寿命做出最终判断之前，这可能导致更换 D6224 和 D4378 )，具有测量废油剩余氧化寿命的能力。 5.1.1 本试验方法适用于非锌汽轮机油。这些是精炼矿物油，含有防锈剂和氧化抑制剂，但不含抗磨添加剂。对于抗磨油，尚未建立具有足够精度的本试验方法。 5.2 该测试方法也适用于制造控制和规范验收。 5.3 当对被典型受阻酚抗氧化剂抑制的汽轮机油进行伏安分析时，产生的伏安图电流在3.5%之间增加 s到5 s（或0.3 V至0.6 V外加电压）（见 注1 )在基本测试溶液中( 图1 — x -轴1秒 = 0.1 五） 。通过伏安分析检测到的受阻酚抗氧化剂包括但不限于2,6-二叔丁基-4-甲基苯酚；2,6-二叔丁基苯酚和4,4'- 亚甲基双（2,6-二叔丁基苯酚）。 注1: 相对于参比电极列出的电压。中所示的伏安图 无花果。1和 2. 使用铂参比电极和0.1V/s的电压扫描速率获得。 图2 碱性试验溶液中的胺和受阻酚峰，空白响应为零 注1: x -轴线 = 时间（秒）和 y -轴是当前的（任意单位）。顶行输入 图2 是新鲜油，下面的管线是用过的油。 5.4 对于含有芳香（芳基）胺化合物（抗氧化剂和缓蚀剂）的非锌汽轮机油，产生的伏安图电流在7.5%之间增加 s到11 s（0.7 V至1.1 V施加电压 图2 )（参见 注1 )不会干扰基本测试溶液中受阻酚的测量。有关这些芳香胺抗氧化剂的测量，请参阅测试方法 D6971 ，其中应使用中性试验溶液。

1.1 This test method covers the voltammetric determination of hindered phenol antioxidants in new or in-service non-zinc turbine oils in concentrations from 0.0075 % by weight up to concentrations found in new oils by measuring the amount of current flow at a specified voltage in the produced voltammogram. 1.2 The values stated in SI units are to be regarded as 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 The quantitative determination of hindered phenol antioxidants in a new turbine oil measures the amount of this material that has been added to the oil as protection against oxidation. Beside phenols, turbine oils can be formulated with other antioxidants such as amines which can extend the oil life. In used oil, the determination measures the amount of original (phenolic) antioxidant remaining after oxidation have reduced its initial concentration. This test method is not designed or intended to detect all of the antioxidant intermediates formed during the thermal and oxidative stressing of the oils, which are recognized as having some contribution to the remaining useful life of the used or in-service oil. Nor does it measure the overall stability of an oil, which is determined by the total contribution of all species present. Before making final judgment on the remaining useful life of the used oil, which might result in the replacement of the oil reservoir, it is advised to perform additional analytical techniques (in accordance with Practices D6224 and D4378 ), having the capability of measuring remaining oxidative life of the used oil. 5.1.1 This test method is applicable to non-zinc turbine oils. These are refined mineral oils containing rust and oxidation inhibitors, but not antiwear additives. This test method has not yet been established with sufficient precision for antiwear oils. 5.2 This test method is also suitable for manufacturing control and specification acceptance. 5.3 When a voltammetric analysis is obtained for a turbine oil inhibited with a typical hindered phenol antioxidant, there is an increase in the current of the produced voltammogram between 3 s to 5 s (or 0.3 V to 0.6 V applied voltage) (see Note 1 ) in the basic test solution ( Fig. 1 — x -axis 1 second = 0.1 V). Hindered phenol antioxidants detected by voltammetric analysis include, but are not limited to, 2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butylphenol and 4,4'-methylenebis(2,6-di-tert-butylphenol). Note 1: Voltages listed with respect to reference electrode. The voltammograms shown in Figs. 1 and 2 were obtained with a platinum reference electrode and a voltage scan rate of 0.1 V/s. FIG. 2 Amine and Hindered Phenols Peaks in the Basic Test Solution with Blank Response Zeroed Note 1: x -axis = time (seconds) and y -axis is current (arbitrary units). Top line in Fig. 2 is fresh oil, and lower line is used oil. 5.4 For non-zinc turbine oils containing aromatic (aryl) amine compounds (antioxidants and corrosion inhibitors), there is an increase in the current of the produced voltammogram between 7 s to 11 s (0.7 V to 1.1 V applied voltage in Fig. 2 ) (see Note 1 ) which does not interfere with the hindered phenol measurement in the basic test solution. For the measurement of these aromatic amine antioxidants, refer to Test Method D6971 , where the neutral test solution shall be used.