Determination of film adhesion

The adhesion of the coating film on the substrate includes: the adhesion to the surface of the coated object, as well as the cohesion of the coating film itself. This is a very important quality indicator of the coating system. Obviously, no matter how much performance a coating has, if it cannot firmly adhere to the substrate, it will lose all the meaning of protection. Therefore, when many people are discussing the anti-corrosion mechanism of coatings, the adhesion strength of the coating film on the protected object is an indicator that cannot be ignored.

The detection methods stipulated in my country's national standards are: GB1720, that is, the scribing method; GB9286 is the scribing method; GB5210 is the pulling method. The international standard ISO2409 is the scribing method, and ISO4624 is the pulling method. The American Society for Testing and Materials standard ASTM D2197 stipulates two methods. Method A is "scratch adhesion". On a test instrument called balance bar scratch irradiation, the oil-coated sample is placed under a rounded stylus or ring, and the load on it is gradually increased. Until the coating is detached from the surface of the substrate, the adhesion of the material is measured once. This method is similar to the scribing method in my passing standard. The other is "parallel groove line adhesion", which is similar to the scribing method in my country's standard. The American standard ASTM D3359 further requires sticking the loose coating film with tape after scratches to measure its adhesion.

(NBCHAO recommends that you use a grid to measure the adhesion of the coating)