QB/T 3825-1999 《Testing method of the white chromatic conversion coatings existance and the corrosion resistance of the zinc deposits for the light industrial products》 Related products

This method is used to evaluate the performance of galvanized passivating films. First, the presence of the film is detected by formulating a lead acetate solution with a specific pH value. Drop the solution on the surface of the sample and observe whether there are dark deposits or dark spots to determine the presence or absence of the film. Then, the corrosion resistance test of the white passivating film is carried out. This test requires the use of a Constant Temperature and Humidity Chamber. The sample is exposed to a certain temperature and Humidity conditions for a certain period to observe whether the sample has film damage or the formation of white corrosion products after the cycle test. When evaluating the results, slight speckles should be ignored, but the samples after each cycle need to be inspected.