The pores of the coating refer to the small pores from the surface of the coating to the base metal. The size of the pores affects the protective ability of the coating. Methods for measuring pores include filtering method, paste method, dipping method, etc.

Filter paper pasting method: Paste the wet paper soaked in the test solution on the pre-treated surface to be tested. The test solution on the filter paper penetrates into the pores and interacts with the intermediate coating or base metal to generate spots with physical characteristics on the filter paper. show. Then evaluate the porosity of the coating based on the number of stains on the filter paper.

Paste method: Apply a paste containing the corresponding test solution to the test sample. The test solution in the paste penetrates into the pores of the coating and interacts with the base metal or intermediate coating to form spots with characteristic colors. According to these spots, To evaluate the porosity of the coating.

Immersion method: Immerse the sample in the corresponding test solution. The test solution penetrates into the pores of the coating and interacts with the base metal or intermediate coating to produce colored spots on the surface of the coating. Then check the number of colored spots on the surface of the coating to evaluate the porosity of the coating. This method is suitable for testing the porosity of cathodic coatings on the surface of steel, copper or copper alloy and aluminum alloy substrates.