Downloaded from https://www.everyspec.com MIL-STD-81OC b. This test can also be used to detect the presence of free iron contaminatingthe surface of another metal by inspection of the corrosion products. the APPARATUS. The apparatus used in the salt fog test shall include following: a. Exposure chamber with racks for supporting test items, b. Salt solution reservoir with means for maintaining an adequate level of solution. c. Means for atomizing salt solution, including suitable nozzles and compressed air supply. d. Chamber heating means and control. e. Means for humidifying the air at a temperature above the chamber temperature. 2.1 Chamber.
The chamber and al1 accessories shall be made of material that will not affect the corrosivenessof the fog, e.g., glass, hard rubber, plastic, or kiln dried wood other than plywood. In addition, all parts which come in contact with test items shall be of materials that will not cause electrolytic corrosion. The chamber and accessories shall be constructed and arranged so that there is no direct impingementof the fog or dripping of the condensate on the test items, that the fog circulates freely about all test items to the same degree, and that no liquid which has come in contact with the test items returns to the salt-solution reservoir.
The chamber shall be properly vented to prevent pressure buildup. and allow uniform distributionof salt fog. The discharge end of the vent shall be protected from stro~ drafts which can create strong air currents in the test chamber. 2.2 Atomizers; The atomizers used shall be of such design and construction as to produce a finely divided, wet, dense fog. Atomizing nozzles shall be made of material that is nonreactive to the salt solution. 2.3 Air supply. The compressed air entering the atomizer shall be essentially free from al1 impurities, such as oil and dirt, Means shall be provided to humidify and warm the compressed air as required to meet the operating conditions.
The air pressure shal1 be suitable to produce a finely 509.1-2 METHOD 509.1