1.1 本测试标准涵盖了使用磷钼酸（PMA）检测严重缺陷和机械损伤的设备和方法，包括金、银或钯金属涂层的磨损。这些金属包括镍、铜或铜合金基底上最顶层的金属层。 1.2 文献中可以找到孔隙度测试的最新综述，其中包括针对严重缺陷的孔隙度测试和测试方法。 2. , 3. ASTM《电镀层和相关金属涂层孔隙度和总缺陷测试的选择指南》可用作指南 B765 . 其他相关孔隙度和总缺陷测试标准为测试方法 B735型 , B741 , B798 , B799 , B809 和 B866 ，规格 B488页 , B679 和 B689 . 1.3 以国际单位制表示的数值是首选单位。 括号内的内容仅供参考。 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 PMA测试的主要目的是确定涂层中是否存在机械损伤、磨损和其他严重缺陷。 大多数金属涂层旨在起到保护作用，严重缺陷的存在表明这种保护作用严重降低。 5.2 良好涂覆的涂层提供的保护可能会因电镀后的不当处理或测试期间或使用期间的磨损或机械损伤而减少。PMA测试可用于指示此类损坏的存在。 5.3 该测试用于检测在相对运动（电触点配合）期间因正常磨损或机械损伤而暴露的底板和基材金属。因此，这是一种敏感的通过/失败测试，如果正确执行，将快速检测到基底金属的磨损或进入基底金属层的划痕。 5.4 该测试对小孔相对不敏感。 它不是为一般孔隙度测试而设计的，因此不应使用。孔隙的检测将取决于其大小和试剂保持为液体的时间长度。 5.5 该测试无法区分磨损程度或磨损是镍还是铜。一旦暴露基底金属，就会形成有色钼络合物。虽然在应用PMA后，可以立即在液滴底部将相对较小的区域缺陷（与液滴面积相比）视为微小的有色区域，但任何较大面积的暴露基底金属都会导致整个液滴立即变暗。 5.6 PMA测试还检测暴露底板和基板金属的机械损伤。这种损坏可能发生在任何电镀后操作中，甚至在电镀操作结束时。 在装配操作中，电镀零件通过机械设备装配成较大的单元，这种情况经常发生。 5.7 PMA测试确定暴露基底金属的位置。这些暴露区域的范围和位置可能对性能有害，也可能不有害。建议不要将PMA测试用于预测产品性能，也不要将其用于模拟现场失效机制。对于此类接触性能评估，应使用已知的模拟实际故障机制的环境测试。 5.8 PMA测试主要用于评估单个样本，而不是大样本批次，因为评估通常在显微镜下一次进行一次（见第节） 10 ). 5.9 此测试具有破坏性。任何暴露于PMA测试的零件不得投入使用。

1.1 This test standard covers equipment and methods for using phosphomolybdic acid (PMA) to detect gross defects and mechanical damage including wear through in metallic coatings of gold, silver, or palladium. These metals comprise the topmost metallic layers over substrates of nickel, copper, or copper alloys. 1.2 Recent reviews of porosity testing, which include those for gross defects, and testing methods can be found in the literature. 2 , 3 An ASTM guide to the selection of porosity and gross defect tests for electrodeposits and related metallic coatings is available as Guide B765 . Other related porosity and gross defects test standards are Test Methods B735 , B741 , B798 , B799 , B809 , and B866 , Specifications B488 , B679 ,and B689 . 1.3 The values stated in SI units are the preferred units. Those in parentheses are for information only. 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 The primary purpose of the PMA test is to determine the presence of mechanical damage, wear through, and other gross defects in the coating. Most metallic coatings are intended to be protective, and the presence of gross defects indicates a serious reduction of such protection. 5.2 The protection afforded by well applied coatings may be diminished by improper handling following plating or as a result of wear or mechanical damage during testing or while in service. The PMA test can serve to indicate the existence of such damage. 5.3 This test is used to detect underplate and substrate metal exposed through normal wear during relative motions (mating of electrical contacts) or through mechanical damage. As such, it is a sensitive pass/fail test and, if properly performed, will rapidly detect wear through to base metals or scratches that enter the base metal layers. 5.4 This test is relatively insensitive to small pores. It is not designed to be a general porosity test and shall not be used as such. The detection of pores will depend upon their sizes and the length of time that the reagent remains a liquid. 5.5 This test cannot distinguish degrees of wear through or whether the wear through is to nickel or copper. Once base metal is exposed, the colored molybdenum complex is formed. While relatively small area defects (compared to the area of the droplet) may be seen at the bottom of the drop as tiny colored regions immediately after applying the PMA, any larger areas of exposed base metal will cause the entire droplet to turn dark instantly. 5.6 The PMA test also detects mechanical damage that exposes underplate and substrate metal. Such damage may occur in any postplating operation or even at the end of the plating operation. It can often occur in assembly operations where plated parts are assembled into larger units by mechanical equipment. 5.7 The PMA test identifies the locations of exposed base metal. The extent and location of these exposed areas may or may not be detrimental to performance. The PMA test is not recommended for predictions of product performance, nor is it intended to simulate field failure mechanisms. For such contact performance evaluations, an environmental test known to simulate actual failure mechanisms should be used. 5.8 The PMA test is primarily intended for the evaluation of individual samples rather than large sample lots, since evaluations are normally carried out one at a time under the microscope (see Section 10 ). 5.9 This test is destructive. Any parts exposed to the PMA test shall not be placed in service.