The best coatings for corrosion protection provide not only barriers to the environment , but also a controlled release of a corrosion inhibitor , as demanded by the presence of corrosion or mechanical damage . NASA has developed pH sensitive microcapsules ( patent pending ) that can release their core contents when corrosion starts . The objectives of the research presented here were to encapsulate non - toxic corrosion inhibitors , to incorporate the encapsulated inhibitors into paint formulations , and to test the ability of the paints to control corrosion . Results showed that the encapsulated corrosion inhibitors , specifically Ce(NO3)3 , are effective to control corrosion over long periods of time when incorporated at relatively high pigment volume concentrations into a paint formulation .