GB/T 24195 "Corrosion acid mist of metals and alloys, cyclic accelerated corrosion test under "dry" and "wet" conditions" stipulates two methods:
Method A is only applicable to metals and their alloys, metal coatings (cathode coatings), anodic oxidation coatings, organic coatings on metal materials, etc.
Method B is mainly applicable to anodic coatings on steel plates, anodic coatings with conversion films, etc.
The cyclic corrosion process is divided into acid corrosion, salt spray corrosion, drying and moisturizing
The solution is 5% acidic sodium chloride solution, and the pH is controlled at 3.5+0.1.
Method A In the test, the sample placement angle and vertical direction should be 20°±5°, the salt mist collection area should be 80 cm, and the salt mist sedimentation rate should be within the range of (1.5+0.5) ml/h after 24 hours of continuous spraying . The test cycle depends on the degree of corrosion of the parts, generally within 3 to 180 cycles.
The cyclic process of method B - the corrosion process is also divided into three stages: acid salt spray corrosion, drying and moisturizing. The corrosion solution is a mixed acidified salt solution
The sample placement angle and salt spray deposition rate of method B are the same as method a, and the test cycle is also determined according to the corrosion degree of the parts, generally selected within 12~192 cycles.
According to the provisions of GB/T 24195, the sample should be dried naturally for 1 hour after the test, and then cleaned and evaluated with clean water. There should be no obvious change in appearance after the test, and the number and distribution of corrosion defects should comply with GB/T 6461 "Metal and metal substrate after corrosion test". The mechanical and electrochemical properties shall not be changed according to the provisions of "Rating of Specimens and Test Specimens with Other Inorganic Coatings" (equivalent to ISO 10289).
