The method specified in this appendix is capable of measuring the porosity reaching the substrate in copper plating on a steel substrate.
A1 filter paper method
A11 This method is applicable to parts whose test surface allows a certain area of filter paper to be attached.
A1.2 Test solution
Prepare a solution containing the following ingredients in distilled water;
Ferricyanide {K3[Fe(CN)6]}10g/L
Sodium chloride (NaCl) 20g/L
Reagent grade: chemically pure
A1.3 Test procedure
The test environment should be kept clean to avoid iron dust in the air.
Use ethanol or other appropriate degreasing agents to effectively remove oil stains on the surface to be tested, rinse with distilled water and dry. The parts just out of the plating tank do not need to be degreased.
Dip a filter paper strip with a certain wet strength into the A1.2 solution, and then stick it tightly on the surface to be tested. There is no gap between the filter paper and the test surface, and keep it for 20 minutes. During the test, the filter paper should be kept wet. .
Remove the filter paper and observe the surface of the contact angle with the coating. If there are pores in the coating that reach the substrate, there will be blue marks.
A1.4 Calculation of porosity
Place the plexiglass plate engraved with squares (1cm2 in size) on the test filter paper with traces of pores printed on it. Record the test area and the number of pores, and calculate the porosity (number per square centimeter). If necessary, measure and record the size, quantity and unit area (eg 1cm2) of the largest pore or the maximum number of pores in a specified area, and state it in the test report.
A2 dipping method
A2.1 This method is applicable to parts of any size and shape.
A2.2 Test solution
Prepare a solution containing the following components in distilled water:
Ferricyanide {K3〔Fe(CN)6)}10g/L
Sodium chloride (NaCl) 15g/L
White gelatin 20g/L
Reagent grade: chemically pure
3 test steps
Treat the part to be tested according to the requirements of A1.3, then immerse in the solution of A2.2, take it out for observation after 5min, if there are pores in the coating that reach the substrate, blue spots will appear.
4 Calculation of porosity
Carefully measure the surface area and the number of blue spots immersed in the solution, and calculate the porosity (number per square centimeter). Or handle it as in A1.4.
