Technicians using salt fog machines
ISO 9227 is a type of corrosion test performed in artificial atmospheres. It denotes one of three types of salt spray tests: salt fog, acetic acid salt fog, and copper accelerated salt fog. Salt fog testing is a widely used form of corrosion testing, proven effective for determining how corrosion affects the appearance or functionality of a product. This type of test can be useful for:
Neutral Salt Spray
The most basic type of ISO 9227 test is the neutral salt spray, or NSS. The NSS uses a standard 5% NaCl solution and is performed at a pH between 6.5 and 7.2. This test applies to metals and alloys, conversion coatings, metallic coatings, anodic oxide coatings, and organic coatings on metallic materials.
Acetic Acid Salt Spray
The acetic acid salt spray (AASS) is a type of ISO 9227 test that introduces glacial acetic acid into the standard NaCl solution to achieve the test’s standard pH range. The AASS test is performed in a pH range from 3.1 to 3.3—much lower than the neutral salt spray test. This variation of the ISO 9227 tests decorative coatings of copper, nickel, and chromium.
Copper Accelerated Acetic Acid-Salt Spray (CASS)
The CASS test is an accelerated corrosion test used to determine the protective properties of chrome- and nickel-plated parts. It introduces copper chloride into the standard NaCl solution. Exposure duration is typically determined by whether the corrosion resistance being tested is for appearance or functional purposes. However, because the CASS test solution is more aggressive than the standard NSS solution, exposures typically do not exceed 48 hours. This makes it a quick, cost-effective method for evaluating corrosive performance. This test is commonly used on materials designed for severe conditions, such as decorative copper, nickel, or chromium; it may also apply to nickel or chromium coatings on steel, zinc alloys, aluminum alloys, and plastics.
ATS ISO 9227 Testing
ATS has a testing facility with up-to-date equipment capable of meeting ISO 9227 A2LA accredited standards. Our knowledgeable staff will provide exceptional customer service, reporting in a timely manner. An ATS report may include any or all of the following:
If your product or equipment could benefit from ISO 9227 testing, contact ATS today. We take a closer look.

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