Salt fog tests

The most common of the spray tests is the salt-spray or salt-fog test which was developed originally by Capp in 1914 for studying the protective values of metallic coatings on steel under conditions that he hoped would simulate exposure to a sea-coast atmosphere. Since then the test has been used for a number of purposes, for many of which it is not well suited Although there is no standard size or shape of salt-spray box certain other features of the test have been standardised in ASTM B117 1990. Various... 

For the salt fog test, ASTM-B117, panels were placed on a rack in a salt fog spray for 500 or 1000 hours at a... 

Metallic corrosion is an electrochemical process associated with the flow of current between surface sites having a difference in electrochemical potential. The assessment and evaluation of organic coatings to prevent metal corrosion has traditionally been accomplished through salt fog testing (ASTM B-117) and long term exposure tests in particular service environments. Electrochemical techniques have often been considered (, but are not routinely employed in practice. 

In all the paint systems tested in the atmosphere, the presence of the chloride contaminant at its highest concentration, causes the appearance of small blisters. Such blisters may in time burst due to the oxide built-up inside them, as was seen in the case in the CR system ("Table III.") In the P system ("Table III."), the blistering seen with the third level of chlorides continues after two years outdoor exposure, without rust coming through the coating. This same effect is also seen in salt fog test panels, but it does not appear in those test specimens subjected to accelerated weathering tests. 

Nevertheless, there were reliable reports of corrosion occurring with molybdenum disulphide in films and in greases. Several such reports arose from the US Army , originating with a salt fog test of a missile launcher in which all parts coated with solid film lubricant rusted badly. Subsequent reports described galvanic corrosion of various metals with molybdenum disulphide in moist atmospheres. 

Metallic Mat Testing Combustion, Noise, Pressure Drop, Creep, and Salt Fog Tests.509... 

Air Product and Chemicals, Inc. (USA) have found out that (in the absence of any topcoat) while the doped electrically conductive form of PAni performed well as a corrosion-resistant coating for carbon steel, the undoped, nonconductive form of PAni performed better. This was determined by electrochemical impedance spectroscopy (EIS), immersion testing (3wt % NaCl) and salt fog testing. Perfect performance of undoped PAni could be understood as follows. From the high pore-resistance value observed (2-10 U) it can be concluded that PAni forms a dense, adherent, low porosity film on carbon steel. Such a film would restrict the access of components required for corrosion to occur ... 

One of the most common accelerated exposure tests is the salt spray or salt fog test described in ASTM B117 [84]. In this test, samples are exposed to a spray or fog of 5% NaCl solution at 30 C. Several US military specifications require salt fog testing, and many corrosion engineers have considerable experience with this test. It is therefore of use as a qualification procedure to evaluate materials. However, the results of salt spray testing do not always correlate with other types of exposure, and considerable variability in test results is not uncommon. 

A compilation of modified salt fog tests, ASTM G 85, includes five annexes. The first. Acetic Acid Salt Spray (Fog) Testing, was originally published as ASTM B 287. In this annex, the salt solution is prepared in accordance with B 117, then tidjusted to a pH in the 3.1-3.3 range with the acetic acid. The acetic acid salt spray test is used for decorative chromium plating on steel [4]. The test duration is typically 144-240 h. 

The second annex. Cyclic Acidified Salt Fog Testing, originally ASTM G 43, was used for exfoliation testing on certain aluminum alloys [4]. It is often referred to as the... 

Liu, T., Is the Salt Fog Test an Effective Method to Evaluate Corrosion Resistant Coatings Corrosion Control by Organic Coatings, H. Leidheiser, Jr., Ed., National Association of Corrosion Engineers, Houston, TX, 1981, pp. 247-254. 

After the equipment is exposed to the salt fog test it is required to operate without malfunctions. Diying out time may or may not be allowed. 

Osborne (2001 o, b) AI-2024-T3 Zr02 + SI02 Commercial sol (Boeget-EPii) Salt fog tests Not protective coating without Inhibitors... 

Figure 11.33 Controlled salt fog test chamber during a humid cycle.

HOURS OF EXPOSURE TO FIRST SIGNIFICANT RUST ASTMB117 Salt Fog Test... 

Wet storage, alternating climate, and salt fog test are used to test for corrosion. The latter is typically applied when metallic accessories or inserts for plastics fuel containers are qualified. Alternating moisture tests allow sufficient swelling of the plastic containers and help detect any loosening of welded-on fixtures or potential corrosion on the metallic parts inside the tank [515],... 

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