1.1 本试验方法涵盖了通过恒流库仑技术（也称为阴极还原法）测定金属表面腐蚀和变色膜（包括氧化物）相对堆积的程序和设备。 1.2 该测试方法主要用于确定由气体环境测试产生的对照试样上失去光泽膜的相对数量，特别是当后者用于测试包含在客户产品环境中使用的电触点的部件或系统时。 1.3 该测试方法也可用于评估暴露于室内工业场所或其他特定应用环境的测试样品。（见 4.6 限制。） 1.4 该测试方法已被证明特别适用于铜和银测试样品（见 ( 1 ) ). 2 其他金属需要进一步研究，以证明其在本试验方法范围内的适用性。 1.5 以SI单位表示的值是优选的单位。括号中提供的值仅供参考。 1.6 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任熟悉所有危害，包括制造商提供的本产品/材料的适当材料安全数据表（MSDS）中确定的危害，建立适当的安全、健康和环境实践，并在使用前确定法规限制的适用性。 1.7 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的标准化原则制定的贸易壁垒委员会。 ======意义和用途====== 4.1 具有导电表面的材料的环境测试的当前趋势是在加速的实验室条件下产生类似于在使用环境中引起故障的腐蚀和成膜反应。在许多这些程序中，被测部件暴露于受控量的水蒸气和污染物气体中数天或数周，这些气体可能以极其稀释的浓度存在。 附注2: 这种测试的描述可以在实践中找到 B827 . 4.2 许多这些环境测试方法需要在测试期间监测室内的条件，以确认预期的环境相关反应实际上正在发生。最常见的监测器类型由铜、银或其他几平方厘米的薄金属试样组成，这些试样放置在测试室内，与腐蚀环境的反应方式与被测零件的重要表面大致相同。 4.3 在实践中，在每个指定位置放置最少数量的对照试样（见试验方法 B810 )在室内进行指定的暴露时间，这取决于测试环境的严重程度。在该时间间隔结束时，取出金属样品并通过库仑还原程序进行分析。 4.4 用于金属试样的其他腐蚀膜评估技术也是可用的。其中最常见的是质量增加，它对表面膜无害，但仅限于确定金属因环境侵蚀而获得的额外质量的总量。最常见的是使用高性能微量天平称重，或出于实时监测的目的，使用石英晶体微量天平（参见规格 B808 ). 附注3: 进行此类称重以及试样清洁和表面处理程序的详细说明包含在测试方法中 B810 . 附注4: 一些表面分析技术(例如X射线方法)可以提供膜中一些化合物的非破坏性鉴定，但是这样的方法，例如X射线衍射，可以漏掉无定形化合物和以小于失去光泽的膜体积的5%的量存在的化合物。 4.5 利用库仑技术，有可能将复杂的总膜分解成许多单独的组分（ 图1 )以便进行比较。这种解析能力提供了 指纹 能够识别与预期测试条件的显著偏差，以及比较不同环境室和同一室内不同测试运行的腐蚀特性。 4.6 库仑还原程序也可用于测试开发和评估暴露于工业或其它应用环境中的测试样品 ( 7 ) 然而，对于室外暴露，可能必须对允许的腐蚀产物的数量和类型施加一些限制，特别是那些涉及水分冷凝和由于剥落而可能损失的腐蚀产物（另见 4.9 和 8.3.2 ). 4.7 在实验室环境测试中，在对给定腐蚀环境进行重复表征以建立该环境的特征还原曲线后，库仑还原程序最有用。这些多次运行应来自在给定测试暴露范围内使用多个样本以及在相同测试条件下连续进行的几次测试运行。 4.8 库仑还原过程是破坏性的，因为失去光泽的膜在电化学还原过程中被转化。无损评估方法，例如质量增益，可以用待库仑测试的相同样品进行。然而，这样的程序必须先于库仑还原。 4.9 本试验方法中规定的条件主要用于总标称厚度为10 2 至10 3 纳米（10 3 至10 4 哦）。比10厚得多的环保生产薄膜 3 纳米通常粘附性差，并且在放置在电解质溶液中时更可能经历松动或剥落。

1.1 This test method covers procedures and equipment for determining the relative buildup of corrosion and tarnish films (including oxides) on metal surfaces by the constant-current coulometric technique, also known as the cathodic reduction method. 1.2 This test method is designed primarily to determine the relative quantities of tarnish films on control coupons that result from gaseous environmental tests, particularly when the latter are used for testing components or systems containing electrical contacts used in customer product environments. 1.3 This test method may also be used to evaluate test samples that have been exposed to indoor industrial locations or other specific application environments. (See 4.6 for limitations.) 1.4 This test method has been demonstrated to be applicable particularly to copper and silver test samples (see ( 1 ) ). 2 Other metals require further study to prove their applicability within the scope of this test method. 1.5 The values stated in SI units are the preferred units. The values provided in parentheses are for information only. 1.6 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 become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use. 1.7 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 ====== 4.1 The present trend in environmental testing of materials with electrically conductive surfaces is to produce, under accelerated laboratory conditions, corrosion and film-forming reactions that are similar to those that cause failures in service environments. In many of these procedures the parts under test are exposed for days or weeks to controlled quantities of both water vapor and pollutant gases, which may be present in extremely dilute concentrations. Note 2: Descriptions of such tests can be found in Practice B827 . 4.2 Many of these environmental test methods require monitoring of the conditions within the chamber during the test in order to confirm that the intended environmentally related reactions are actually taking place. The most common type of monitor consists of copper, silver, or other thin metallic coupons of a few square centimeters that are placed within the test chamber and that react with the corrosive environment in much the same way as the significant surfaces of the parts under test. 4.3 In practice, a minimum number of control coupons are placed in each specified location (see Test Method B810 ) within the chamber for a specified exposure time, depending upon the severity of the test environment. At the end of this time interval, the metal samples are removed and analyzed by the coulometric reduction procedure. 4.4 Other corrosion film evaluation techniques for metallic coupons are also available. The most common of these is mass gain, which is nondestructive to the surface films, but is limited to the determination of the total amount of additional mass acquired by the metal as a result of the environmental attack. The most common is weighing using high performance microbalances or for purposes of real-time monitoring, quartz crystal microbalances (see Specification B808 ). Note 3: Detailed instructions for conducting such weighings, as well as coupon cleaning and surface preparation procedures, are included as part of Test Method B810 . Note 4: Some surface analytical techniques (such as X-ray methods) can provide nondestructive identification of some compounds in the films, but such methods, for example, X-ray diffraction, can miss amorphous compounds and compounds present in quantities less than 5 % of the tarnish film volume. 4.5 With the coulometric technique, it is possible to resolve the complex total film into a number of individual components ( Fig. 1 ) so that comparisons can be made. This resolving power provides a fingerprint capability for identifying significant deviations from intended test conditions, and a comparison of the corrosive characteristics of different environmental chambers and of different test runs within the same chamber. 4.6 The coulometric reduction procedure can also be used in test development and in the evaluation of test samples that have been exposed at industrial or other application environments ( 7 ) . However, for outdoor exposures, some constraints may have to be put on the amount and type of corrosion products allowed, particularly those involving moisture condensation and the possible loss of films due to flaking (also see 4.9 and 8.3.2 ). 4.7 In laboratory environmental testing, the coulometric-reduction procedure is of greatest utility after repeated characterizations of a given corrosive environment have been made to establish a characteristic reduction curve for that environment. These multiple runs should come from both the use of multiple specimens within a given test exposure as well as from several consecutive test runs with the same test conditions. 4.8 The coulometric-reduction procedure is destructive in that the tarnish films are transformed during the electrochemical reduction process. Nondestructive evaluation methods, such as mass gain, can be carried out with the same samples that are to be tested coulometrically. However, such procedures must precede coulometric reduction. 4.9 The conditions specified in this test method are intended primarily for tarnish films whose total nominal thickness is of the order of 10 2 to 10 3 nm (10 3 to 10 4 Å). Environmentally produced films that are much thicker than 10 3 nm are often poorly adherent and are more likely to undergo loosening or flaking upon placement in the electrolyte solution.