The integrity of the coating is an important part of its ability to adhere to and protect a substrate. If the coating film is porous, the strength and integrity of the coating can be significantly reduced and could cause premature failure. To help determine the coating’s integrity, the porosity of a cross-section and at the coating substrate interface is examined. The interface and cross section porosity of coatings are typically examined with a microscope at 40X magnification. According to CAN/CSA Z245.20, Clause 12.10, both interface and cross-section porosity are ranked between 1 and 5, with 1 indicating the lowest and 5 the highest porosity.
- CSA Z245.20 Section 12.10
- ISO 21809-2
Example of coating cross section porosity