1.1本试验方法包括监测在用石油和碳氢化合物润滑油中的氧化，如柴油曲轴箱、电机、液压、齿轮和压缩机油，以及其他易于氧化的润滑油。 1.2本试验方法使用傅立叶变换红外光谱法（FT-IR）监测在用石油和碳氢化合物润滑油中正常机械操作产生的氧化产物。石油和碳氢化合物基润滑剂与空气中的氧反应，形成许多不同的化学物质，包括醛、酮、酯和羧酸。 该测试方法设计为一种快速、简单的光谱检查，用于监测在用石油和碳氢化合物润滑油中的氧化情况，目的是通过测量油中的氧化程度来帮助诊断机器的运行状况。 1.3实施规程D 7418中描述了用于测量在役油和润滑剂样品中氧化的FT-IR光谱数据的采集 . 在该测试方法中，介绍了使用直接趋势分析和差分（谱减法）趋势分析的氧化测量和数据解释参数。 1.4本试验方法基于与在用石油和烃基润滑剂氧化相关的光谱变化趋势。可以根据单个测量的固定最小值设置警告或报警限值，或者也可以根据测量响应的变化率设置警告或报警限值，参见参考文献（1）。 1.4.1对于直接趋势分析，直接从吸收光谱记录值，并以每0.1 mm光程的吸光度单位报告。 1.4.2对于差分趋势分析，从差分光谱（通过将参考油的吸收光谱从中减去获得的光谱）中记录值- 并以每0.1 mm光程长度100*吸光度为单位报告（或相当于每厘米吸光度单位）。 1.4.3在任何一种情况下，应通过统计分析、相同或类似设备的历史记录、循环试验或其他方法以及氧化变化与设备性能的相关性来确定维护行动限制。 笔记 1-本试验方法的目的不是建立或建议任何机械的正常、警戒、警告或警戒极限。应结合机械制造商和维护小组的建议和指导制定此类限制。 1.5本试验方法适用于石油和烃基润滑剂，不适用于酯基油，包括多元醇酯或磷酸酯。 1.6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。 1.6.1 例外 — 波数单位为厘米 -1 . 1.7 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和健康实践，并确定监管限制的适用性。 ====意义和用途====== 当油与大气中的氧气反应时，会产生大量的化合物，如醛、酮、酯和羧酸。使用1800至1670 cm之间的常见FT-IR光谱特征测量氧化 -1 由大多数氧化化合物中存在的羰基吸收引起。这些氧化产物可能导致粘度增加（引起油稠化问题）、酸性（引起酸性腐蚀）和污泥和清漆的形成（导致过滤器堵塞、临界油隙污垢和阀门摩擦）。 因此，氧化产物的监测是确定整体机械健康状况的一个重要参数，应结合其他测试的数据，如磨损金属分析的原子发射光谱（AE）和原子吸收光谱（AA）（测试方法D 5185）来考虑 )，物理性能试验（试验方法D 445 和D 6304 )，基础储备（试验方法D 2896 和D 4739 )，酸值试验（试验方法D 664 和D 974 )和其他用于硝化的FT-IR油分析方法（实施规程E 2412 )，硫酸盐副产物（试验方法D 7415 )，添加剂消耗（试验方法D 7412 )，分解产物和外部污染物（实施规程E 2412 )它还评估了油的成分 ’ s条件，见参考文献（1-6）。

1.1 This test method covers monitoring oxidation in in-service petroleum and hydrocarbon based lubricants such as in diesel crankcase, motor, hydraulic, gear and compressor oils, as well as other types of lubricants that are prone to oxidation. 1.2 This test method uses Fourier Transform Infrared (FT-IR) spectrometry for monitoring build-up of oxidation products in in-service petroleum and hydrocarbon based lubricants as a result of normal machinery operation. Petroleum and hydrocarbon based lubricants react with oxygen in the air to form a number of different chemical species, including aldehydes, ketones, esters, and carboxylic acids. This test method is designed as a fast, simple spectroscopic check for monitoring of oxidation in in-service petroleum and hydrocarbon based lubricants with the objective of helping diagnose the operational condition of the machine based on measuring the level of oxidation in the oil. 1.3 Acquisition of FT-IR spectral data for measuring oxidation in in-service oil and lubricant samples is described in Practice D 7418 . In this test method, measurement and data interpretation parameters for oxidation using both direct trend analysis and differential (spectral subtraction) trend analysis are presented. 1.4 This test method is based on trending of spectral changes associated with oxidation of in-service petroleum and hydrocarbon based lubricants. Warnings or alarm limits can be set on the basis of a fixed minimum value for a single measurement or, alternatively, can be based on a rate of change of the response measured, see Ref (1). 1.4.1 For direct trend analysis, values are recorded directly from absorption spectra and reported in units of absorbance per 0.1 mm pathlength. 1.4.2 For differential trend analysis, values are recorded from the differential spectra (spectrum obtained by subtraction of the absorption spectrum of the reference oil from that of the in-service oil) and reported in units of 100*absorbance per 0.1 mm pathlength (or equivalently absorbance units per centimetre). 1.4.3 In either case, maintenance action limits should be determined through statistical analysis, history of the same or similar equipment, round robin tests or other methods in conjunction with the correlation of oxidation changes to equipment performance. Note 1—It is not the intent of this test method to establish or recommend normal, cautionary, warning or alert limits for any machinery. Such limits should be established in conjunction with advice and guidance from the machinery manufacturer and maintenance group. 1.5 This test method is for petroleum and hydrocarbon based lubricants and is not applicable for ester based oils, including polyol esters or phosphate esters. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6.1 Exception — The unit for wave numbers is cm -1 . 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== A large number of compounds, such as aldehydes, ketones, esters, and carboxylic acids, are produced when oils react with atmospheric oxygen. Oxidation is measured using a common FT-IR spectral feature between 1800 and 1670 cm -1 caused by the absorption of the carbonyl group present in most oxidation compounds. These oxidation products may lead to increased viscosity (causing oil thickening problems), acidity (causing acidic corrosion), and formation of sludge and varnish (leading to filter plugging, fouling of critical oil clearances and valve friction). Monitoring of oxidation products is therefore an important parameter in determining overall machinery health and should be considered in conjunction with data from other tests such as atomic emission (AE) and atomic absorption (AA) spectroscopy for wear metal analysis (Test Method D 5185 ), physical property tests (Test Methods D 445 and D 6304 ), base reserve (Test Method D 2896 and D 4739 ), acid number tests (Test Methods D 664 and D 974 ) and other FT-IR oil analysis methods for nitration (Practice E 2412 ), sulfate by-products (Test Method D 7415 ), additive depletion (Test Method D 7412 ), breakdown products and external contaminants (Practice E 2412 ), which also assess elements of the oil ’ s condition, see Refs (1-6).