Conclusion

The work described in this article shows that the ultrasonic cavitation test can reliably characterize the adhesion and cohesion of thin coatings. The test is applicable to thin, fragile or even porous coatings, for which most conventional tests are unsuitable. Other types of coating particularly concerned by this test, such as porous coatings made up of microparticles, have to our knowledge not yet been studied by this test. It should be noted, however, that there are experimental and system-specific (film/substrate) limitations to this test, including the difficulty of characterizing the damaged area (optical contrast limit, for example), insufficient adhesion or cohesion of the coating in relation to the stresses produced by cavitation, or the unsuitability of the physico-chemical properties of the liquid environment required for cavitation. In our view, a useful and necessary development...