1.1 本试验方法涵盖了新润滑油和在用润滑油中初始pH（i-pH）的测定程序。 注1: 在新的和使用过的油中，可能被认为具有影响i-pH值的特征的成分包括有机酸和无机酸、酯类、酚类化合物、内酯、树脂、重金属盐、氨盐和其他弱碱、多元酸的酸盐以及抑制剂和洗涤剂等添加剂。“初始”用于区分水系统。当未达到平衡条件（如水系统中pH测量所知）时，在规定的时间间隔后终止分析（见 3.1.1 .2) 1.2 本试验方法用于指示在氧化条件下使用期间，或由于沼气燃烧过程中的窜气污染而导致的油中发生的相对变化，无论在用润滑剂的颜色或其他特性如何。虽然初始pH值是在确定的平衡条件下确定的，但该试验方法并非旨在测量可用于预测油在使用条件下的性能的绝对酸性。有色金属的腐蚀与初始pH值之间没有普遍的相关性。 1.3 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。 1.4 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。 1.5 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 新的和使用过的石油产品可能包含作为添加剂存在的酸性成分、在使用过程中形成的降解产物，例如氧化产物或燃烧气体形成的成分。i-pH值是测量酸性物质的量及其在试验条件下定义的酸度。i-pH值用于测量润滑油在使用中的降解。 5.2 酸性成分的腐蚀性取决于其浓度和酸度。i-pH值是对金属具有潜在腐蚀性的离解酸性成分数量的度量。 5.3 由于各种氧化和窜气产物都会影响i-pH值，因此本试验方法不能用于预测在使用条件下油或混合物对金属成分的腐蚀性。i-pH值与混合物或油对金属的腐蚀倾向之间没有普遍的相关性。

1.1 This test method covers procedures for the determination of initial pH (i-pH) in new and in-service lubricants. Note 1: In new and used oils, the constituents that may be considered to have characteristics influencing the i-pH value include organic and inorganic acids, esters, phenolic compounds, lactones, resins, salts of heavy metals, salts of ammonia and other weak bases, acid salts of polybasic acids, and addition agents such as inhibitors and detergents. “Initial” is used to differentiate from aqueous systems. The analysis is terminated after a defined time interval whenever equilibrium conditions, as known for pH measurements in aqueous systems, are not reached (see 3.1.1 .2) 1.2 This test method is used to indicate relative changes that occur in oil during use under oxidizing conditions or due to contamination by blow-by gases of combustion processes of biogases regardless of the color or other properties of the in-service lubricants. Although the initial pH is made under definite equilibrium conditions, the test method is not intended to measure an absolute acidic property that can be used to predict performance of oil under service conditions. No general correlation between corrosion of non-ferrous bearing metals and initial pH value is known. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 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. 1.5 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 New and used petroleum products may contain acidic constituents that are present as additives, degradation products formed during service, such as oxidation products or components formed from combustion gases. The i-pH-value is a measure of the amount of acidic substances and their acidity defined under the conditions of test. The i-pH-value is used as a measure of lubricant degradation in service. 5.2 The corrosiveness of acidic components depends on their concentration and acidity. The i-pH-value is a measure of the amount of dissociated acidic components with the potential of corrosiveness towards metals. 5.3 Since a variety of oxidation and blow-by products contribute to the i-pH-value, this test method cannot be used to predict corrosiveness of oil or blends under service conditions against metallic components. No general correlation is known between i-pH-value and the corrosive tendency of blends or oils toward metals.