1.1 本试验规程涵盖了揭示金和钯涂层孔隙率的设备和方法，特别是电触点上使用的电沉积和覆层金属。 1.2 本试验规程适用于含金或75 % 通常用于电接触的铜、镍及其合金衬底上的钯的质量。 1.3 文献中描述了各种全孔隙度测试方法。 2. , 3. 这些孔隙度测试方法是 B735型 , B741型 , B798型 , B799 和 第809页 《ASTM电沉积和相关金属涂层孔隙率试验选择指南》可作为指南 B765型 . 1.4 以国际单位表示的值应视为标准值。括号中给出的值仅供参考。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。有关具体危害，请参见第节 6. . 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《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 钯和金涂层通常用于可分离电连接器和其他设备的触点。电沉积是触点上最常用的金形式，尽管它也被用作镶嵌或覆层金属以及触点表面的焊件。金和钯合金的内在高贵性使其能够抵抗可能干扰可靠接触操作的绝缘氧化膜的形成。 5.2 为了使这些涂层发挥预期的功能，涂层中暴露基底金属基底和底板的孔隙率、裂缝和其他缺陷必须最小或不存在，除非在结构中使用触点以保护表面不受环境影响，或对沉积物进行腐蚀抑制表面处理是可行的。 涂层中可容忍的孔隙率水平取决于底板或衬底的环境严重性、接触装置的设计因素（如配合力）、电路参数以及必须保持的接触操作可靠性。此外，当存在时，表面上孔隙的位置很重要。如果孔的数量很少，且位于配合面接触区域之外，则通常可以容忍孔的存在。 5.3 如果能够确定接触表面上的孔的精确位置和数量，则确定接触表面的孔的方法是最合适的。 接触表面通常是弯曲的或不规则的，测试方法应适用于它们。此外，孔隙度测定测试的严重程度可能会从能够检测所有孔隙度的程序到仅检测高孔隙度条件的程序有所不同。 5.4 本测试实践能够检测几乎所有可能与基底或底板发生腐蚀反应的孔隙或其他缺陷。此外，它可以用于具有复杂几何形状的触点，例如插针-插座触点（尽管对于深凹槽，最好打开触点结构以允许蒸汽与内部有效表面反应）。 5.5 特定测试所揭示的孔隙率水平与接触行为的关系必须由这些测试的用户通过实际经验或其他形式的测试来确定。因此，涂层中没有孔隙可能是某些应用的要求，而接触区中的少量孔隙可能是其他应用的要求。孔隙腐蚀产物的可接受数量、尺寸和位置应符合相应图纸或规范的规定。 5.6 该试验被认为是破坏性的，因为它通过腐蚀产物污染表面以及在孔隙位置或未电镀区域边界处对涂层进行底切来揭示孔隙率的存在。 暴露于该试验的任何部件不得投入使用。 5.7 这个测试既简单又便宜。使用工业实验室中的标准基本设备，与测试相关的成本非常低。与该程序相关的废物处理问题最少。该测试非常受欢迎，因为它可以快速评估电镀质量问题的可能性，然后以更高的成本进行1-2周的加速环境测试。

1.1 This test practice covers equipment and methods for revealing the porosity of gold and palladium coatings, particularly electrodeposits and clad metals used on electrical contacts. 1.2 This test practice is suitable for coatings containing gold or 75 % by mass of palladium on substrates of copper, nickel, and their alloys, which are commonly used in electrical contacts. 1.3 A variety of full porosity testing methods is described in the literature. 2 , 3 These porosity Test Methods are B735 , B741 , B798 , B799 , and B809 . An ASTM Guide to the selection of porosity tests for electrodeposits and related metallic coatings is available as Guide B765 . 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.5 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. For specific hazards, see Section 6 . 1.6 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 Palladium and gold coatings are often specified for the contacts of separable electrical connectors and other devices. Electrodeposits are the form of gold that is most used on contacts, although it is also employed as inlay or clad metal and as weldments on the contact surface. The intrinsic nobility of gold and palladium alloys enables it to resist the formation of insulating oxide films that could interfere with reliable contact operation. 5.2 In order for these coatings to function as intended, porosity, cracks, and other defects in the coating that expose base-metal substrates and underplates must be minimal or absent, except in those cases where it is feasible to use the contacts in structures that shield the surface from the environment or where corrosion inhibiting surface treatments for the deposit are employed. The level of porosity in the coating that may be tolerable depends on the severity of the environment to the underplate or substrate, design factors for the contact device like the force with which it is mated, circuit parameters, and the reliability of contact operation that it is necessary to maintain. Also, when present, the location of pores on the surface is important. If the pores are few in number and are outside of the zone of contact of the mating surfaces, their presence can often be tolerated. 5.3 Methods for determining pores on a contact surface are most suitable if they enable their precise location and numbers to be determined. Contact surfaces are often curved or irregular in shape, and testing methods should be suitable for them. In addition, the severity of porosity-determining tests may vary from procedures capable of detecting all porosity to procedures that detect only highly porous conditions. 5.4 The present test practice is capable of detecting virtually all porosity or other defects that could participate in corrosion reactions with the substrate or underplate. In addition, it can be used on contacts having complex geometry such as pin-socket contacts (although with deep recesses it is preferred that the contact structures be opened to permit reaction of the vapors with the interior significant surfaces). 5.5 The relationship of porosity levels revealed by particular tests to contact behavior must be made by the user of these tests through practical experience or by other forms of testing. Thus, absence of porosity in the coating may be a requirement for some applications, while a few pores in the contact zone may be acceptable for others. The acceptable number, sizes and locations of the pore corrosion products shall be as specified on the appropriate drawing or specification. 5.6 This test is considered destructive in that it reveals the presence of porosity by contaminating the surface with corrosion products and by undercutting the coating at pore sites or at the boundaries of the unplated areas. Any parts exposed to this test shall not be placed in service. 5.7 The test is simple and inexpensive. The cost associated with the test is very low, using standard basic equipment found in an industrial laboratory. There are minimal waste disposal issues associated with the procedure. The test is very popular because of its very quick means of assessing the likelihood of plating quality problems, prior to the performance of accelerated environmental testing on the 1 to 2 week scale at much greater expense.