盐雾试验 METHOD 307 SALT FOG

METHOD 307 SALT FOG方法307 盐雾腐蚀1.Scope 范围1.1Purpose 目的The salt fog method is performed to determine the effectiveness of protective coating and finishes on materials. It may also be applied to determine the effects of salt deposits on the physical and electrical aspects of material.盐雾试验是用来确定材料表面的保护涂覆层的有效性，也用来确定盐雾沉积在物体外壳或电气件表面会带来的影响。

1.2Application 应用This practice is applicable to ferrous and nonferrous metals, and also organic and inorganic coatings. Use this method for screening purposes only to evaluate the effectiveness and quality of protective coatings and finishes on material and material coupons, and to locate potential problem areas, quality control deficiencies, design flaws. Etc., in a relatively short period of time.此试验适用于含铁的、不含铁的金属物料，包含有机或无机涂覆层。

工程师可以使用此试验，在相对短的时间内，反映出物料的涂覆层的质量，潜在的薄弱环节，设计缺陷等。

1.3Limitation 局限性a.The test is not intended to duplicate the effects of a marine atmosphere due to variations in chemical composition and concentrations of the various marine and other corrosive environments.a. 此测试方法不是完全模拟沿海大气的影响，因为试验方法不能完全反映沿海大气与其他腐蚀性环境的变化的化学成分及其浓度。

b.It has not been demonstrated that a direct relationship exists between salt fog corrosion and corrosion due to other media.b. 现在还不能证明盐雾腐蚀与其他物质的腐蚀间存在直接的联系。

c.It has not been demonstrated that withstanding the effects of this test guarantees that the test item will prove to be satisfactory under all corrosive conditions.c. 现在还不能证明能经受盐雾腐蚀的物料就能经受所有腐蚀源的腐蚀d.This test is not a substitute for evaluating corrosion caused by humidity and fungus because their effects differ from salt fog effects and the tests are not interchangeable.d. 此试验不能替代潮湿与菌类会引起的预计腐蚀，因为这几类腐蚀源的影响是不同的，因此试验方法是不能互相取代的。

2.Guidance 指南Salt is one of the most pervasive chemical compounds in the world. It is found in the oceans, the atmosphere, ground surfaces, and lakes and rivers. It is impossible to avoid exposure to salt. It coastal regions, this exposure isintensified; in a marine environment, the exposure reaches a maximum. The procedure can be used in a relatively short period of time to locate potential problem areas, design flaws, incompatibility of materials, etc., that is exacerbated by exposure to a salt atmosphere.盐是世界上最具侵蚀性的化合物，可以在生活周围到处存在。

因此不能避免与盐分接触。

在沿海地区，这种接触会被加剧。

在海洋环境中，接触达到最大化。

暴露在盐分环境中，可以使用相对短暂的时间来定位可能的问题地区、设计流程和材料的不兼容性。

2.1Environmental Effects 环境影响The effects of exposure of material to an environment in which salt is present can be divided into three broad categories: physical effects, chemical effects and electrical effects. Some of examples are so follows:a.Corrosion due to electrochemical reaction.电化学反应引起的腐蚀b.Accelerated stress corrosion. 金属超应力引起的腐蚀c.Corrosion of insulation materials and metals.绝缘材料与金属间的腐蚀d.Clogging or binding of moving parts of mechanical components andassemblies.机械器件的堵塞，机械组装件的粘接2.2Test ParameterVariations for the test procedure are limited to the test duration, cycling of exposure and drying periods, salt concentration and salt composition.The item configuration is also an important factor to consider.测试过程中的参数（持续时间、循环、干燥时间、盐分浓度和盐分组成）变化受到范围限制。

产品设置也是同样一个重要因素。

a.Salt Solution 盐分溶解Unless otherwise specified, the salt solution shall be prepared by dissolving 5 ± 1 parts by mass of sodium chloride in 95 parts of water. The salt used shall be sodium chloride containing on the dry basis not more than 0.1% of sodium iodide and not more than 0.5% of total impurities. Do not use anti-caking agents because such agents may act as corrosion inhibitors. Some salts contain additives that may act as corrosion inhibitors; careful attention should be given to the chemical content of the salt.除非特别说明，盐分溶解应这样被准备：5：95的盐与水的配比。

盐一般为钠化合物，包含不超过0.1%的钠和碘混合成分，不超过0.5%的杂质。

禁止使用防结块的添加剂，这些添加剂可能有防腐蚀作用，从而影响测试。

一些盐包含了其他添加剂，如防腐剂。

所以应特别注意盐的成分。

The pH of the salt solution shall be in the range from 6.5 to 7.2 with the temperature at +35︒C±2︒C. To adjust the pH, use diluted chemically pure hydrochloric acid or chemically pure sodium hydroxide. Make the pH measurement either electrometrically or calorimetrically.盐液的PH值在6.5 与7.2之间，温度为+35︒C±2︒C。

可以用稀释的纯盐酸或氢氧化钠来调整PH值。

b.Test Item Configuration 被测物放置The configuration and orientation of the test item during the exposure period of the salt fog test is an important factor in determining the effect of the environment on the test item. Unless otherwise specified, configure the test item and orient it as would be expected during it storage, shipment or use. For test purposes, choose the most sever/critical configuration.在盐雾试验过程中，被测物的放置方式与方位是用来确定试验影响的一个重要因素。