1.1 本试验方法涵盖了一种进行循环恒电流极化（GSCP）的程序，以确定铝合金3003-H14（UNS A93003）局部腐蚀（点蚀和缝隙腐蚀）的相对敏感性 ( 1. ) . 2. 它可以作为其他合金检验的指南 ( 2- 5. ) . 该测试方法还描述了一个程序，可用于检查一个人的实验技术和仪器。 1.2 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。 1.3 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。 1.4 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====== 3.1 在本试验方法中，铝的局部腐蚀敏感性由保护电位表示( E 保护 )由循环电流计极化确定 ( 1. ) . 该电位越高，合金越不容易引发局部腐蚀。本试验方法的结果无意以定量方式与在使用中可能观察到的局部腐蚀传播速度相关联。 3.2 崩溃( E b )，和保护电位( E 保护 )通过循环GSCP方法确定，与铝的恒电位腐蚀试验（浸入式玻璃器皿）结果相关 ( 1. , 6. , 7. ) . 当外加电位比GSCP更负时 E 保护 ，未观察到凹坑萌生。当外加电位比GSCP更为正时 E 保护 ，即使施加的电势小于 E b . 3.2.1 分离时发生严重缝隙腐蚀 E b 和 E 保护 大于等于500 mV，并且 E 保护 小于 −400 mV Vs.SCE（在100 ppm NaCl中） ( 1. , 6. , 8. ) . 对于铝， E 保护 循环GSCP测定的再钝化电位与划痕恒电位法测定的再钝化电位一致 ( 1. , 9 ) . 划痕恒电位法和恒电位法测定 E 保护 与GSCP方法相比，需要更长的测试时间和更复杂的技术。 3.3 DeBerry和Viebeck ( 3- 5. ) 发现击穿电位( E b )（电流动力学极化，类似于GSCP，但没有动力学信息）与表面活性化合物对304L不锈钢局部腐蚀的抑制有很好的相关性。通过避免动电位技术观察到的强烈感应效应，它们达到了准确度和精密度。 3. 4. 如果使用所讨论的特定合金遵循本试验方法，则其将提供（GSCP）测量，以再现其他实验室在其他时间开发的数据。 3.5 E b 和 E 保护 获得的结果基于八个不同实验室的结果，这些实验室遵循使用铝合金3003-H14（UNS A93003）的标准程序。 E b 和 E 保护 包括统计分析，以表明可接受范围。

1.1 This test method covers a procedure for conducting cyclic galvanostaircase polarization (GSCP) to determine relative susceptibility to localized corrosion (pitting and crevice corrosion) for aluminum alloy 3003-H14 (UNS A93003) ( 1 ) . 2 It may serve as guide for examination of other alloys ( 2- 5 ) . This test method also describes a procedure that can be used as a check for one's experimental technique and instrumentation. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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. 1.4 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 ====== 3.1 In this test method, susceptibility to localized corrosion of aluminum is indicated by a protection potential ( E prot ) determined by cyclic galvanostaircase polarization ( 1 ) . The more noble this potential, the less susceptible is the alloy to initiation of localized corrosion. The results of this test method are not intended to correlate in a quantitative manner with the rate of propagation of localized corrosion that one might observe in service. 3.2 The breakdown ( E b ), and protection potentials ( E prot ) determined by the cyclic GSCP method correlate with the constant potential corrosion test (immersion-glassware) result for aluminum ( 1 , 6 , 7 ) . When the applied potential was more negative than the GSCP E prot , no pit initiation was observed. When the applied potential was more positive than the GSCP E prot , pitting occurred even when the applied potential was less negative than E b . 3.2.1 Severe crevice corrosion occurred when the separation of E b and E prot was 500 mV or greater and E prot was less than −400 mV Vs. SCE (in 100 ppm NaCl) ( 1 , 6 , 8 ) . For aluminum, E prot determined by cyclic GSCP agrees with the repassivation potential determined by the scratch potentiostatic method ( 1 , 9 ) . Both the scratch potentiostatic method and the constant potential technique for determination of E prot require much longer test times and are more involved techniques than the GSCP method. 3.3 DeBerry and Viebeck ( 3- 5 ) found that the breakdown potentials ( E b ) (galvanodynamic polarization, similar to GSCP but no kinetic information) had a good correlation with the inhibition of localized corrosion of 304L stainless steel by surface active compounds. They attained accuracy and precision by avoiding the strong induction effect which they observed by the potentiodynamic technique. 3.4 If this test method is followed using the specific alloy discussed it will provide (GSCP) measurements that will reproduce data developed at other times in other laboratories. 3.5 E b and E prot obtained are based on the results from eight different laboratories that followed the standard procedure using aluminum alloy 3003-H14 (UNS A93003). E b and E prot are included with statistical analysis to indicate the acceptable range.