page_title: Salt spray test
section_title: Modified Salt Spray Tests
hierarchical_section_title: Salt spray test / Modified Salt Spray Tests
caption_attribution_description: English: Graph showing the temperature &amp; humidity steps required during modified Salt Spray Test ASTM G85 Annex 1
context_page_description: The salt spray test is a standardized and popular corrosion test method, used to check corrosion resistance of materials and surface coatings. Usually, the materials to be tested are metallic and finished with a surface coating which is intended to provide a degree of corrosion protection to the underlying metal.
  Salt spray testing is an accelerated corrosion test that produces a corrosive attack to coated samples in order to evaluate the suitability of the coating for use as a protective finish. The appearance of corrosion products is evaluated after a pre-determined period of time. Test duration depends on the corrosion resistance of the coating; generally, the more corrosion resistant the coating is, the longer the period of testing before the appearance of corrosion/ rust.
  The salt spray test is one of the most widespread and long-established corrosion tests. ASTM B117 was the first internationally recognized salt spray standard, originally published in 1939. Other important relevant standards are ISO9227, JIS Z 2371 and ASTM G85.
context_section_description: ASTM G85 is the most popular global test standard covering modified salt spray tests. There are five such tests altogether, referred to in ASTM G85 as annexes A1 through to A5.
   Many of these modified tests originally arose within particular industry sector, in order to address the need for a corrosion test capable of replicating the effects of naturally occurring corrosion and accelerate these effects.
  This acceleration arises through the use of chemically altered salt spray solutions, often combined with other test climates and in most cases, the relatively rapid cycling of these test climates over time. Although popular in certain industries, modified salt spray testing has in many cases been superseded by cyclic corrosion testing (CCT) 
  The type of environmental test chambers used for modified salt spray testing to ASTM G85 are generally similar to the chambers used for testing to ASTM B117, but will often have some additional features, such as an automatic climate cycling control system.
  ASTM G85 Annex A1 – Acetic Acid Salt Spray Test (non-cyclic) 
  This test can be used to determine the relative resistance to corrosion of decorative chromium plating on steel and zinc based die casting when exposed to an acetic acid salt spray climate at an elevated temperature. This test is also referred to as an ASS test.
  Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of salt water solution, prepared in accordance with the requirements of the test standard and acidified (pH 3.1–3.3) by the addition of acetic acid. This spray is set to fall-out on to the specimens at a rate of 1–2 ml/80 cm²/hour, in a chamber temperature of 35 °C. This climate is maintained under constant steady state conditions. The test duration is variable.
  ASTM G85 Annex A2 – Acidified Salt Fog Test (cyclic).
  This test can be used to test the relative resistance to corrosion of aluminium alloys when exposed to a changing climate of acetic acid salt spray, followed by air drying, followed by high humidity, all at an elevated temperature. This test is also referred to as a MASTMAASIS test.
  Test specimens are placed in an enclosed chamber, and exposed to a changing climate that comprises the following 3 part repeating cycle. 0.75 hours exposure to a continuous indirect spray of salt water solution, prepared in accordance with the requirements of the test standard and acidified (pH 2.8–3.0) by the addition of acetic acid. This spray is set to fall-out on to the specimens at a rate of 1–2 ml/80 cm²/hour. This is followed by a 2 hour exposure to an air drying (purge) climate. This is followed by 3.25 hours exposure to a high humidity climate which gradually rises to between 65% RH and 95% RH. The entire test cycle is at a constant chamber temperature of 49 °C. The number of cycle repeats and therefore the test duration is variable.
  ASTM G85 Annex A3 – Seawater Acidified Test (cyclic)
  This test can be used to test the relative resistance to corrosion of coated or uncoated aluminium alloys and other metals, when exposed to a changing climate of acidified synthetic seawater spray, followed by a high humidity, both at an elevated temperature. This test is also referred to as a SWAAT test.
  Test specimens are placed in an enclosed chamber, and exposed to a changing climate that comprises the following 2 part repeating cycle. First, a 30 minute exposure to a continuous indirect spray of synthetic seawater solution, prepared in accordance with the requirements of the test standard and acidified (pH 2.8–3.0) by the addition of acetic acid. This spray is set to fall-out on to the specimens at a rate of 1–2 ml/80 cm²/hour. This is followed by a 90 minute exposure to a high humidity climate (above 98% RH). The entire test cycle is at a constant chamber temperature of 49 °C (may be reduced to 24–35 °C for organically coated specimens). The number of cycle repeats and therefore the test duration is variable.
  ASTM G85 Annex A4 – SO
  ₂ Salt Spray Test (cyclic)
  This test can be used to test the relative resistance to corrosion of product sam
caption: Graph showing the temperature & humidity steps required during modified Salt Spray Test ASTM G85 Annex 1
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