The use of classic anticorrosive pigments is beirtg more and more restricted by increasing environmental concems; they are gradually replaced by zinc phosphate and related compounds. Other anticorrosive pigments such as surface exchanged silicas were also proposed The object of this research is to study the anticorrosive properties of calcium acid phosphate as inhibitive pigment introducing a careful selection of complementary pigments in order to achieve an efficient anticorrosive protection. Several paints were prepared and tested through accelerated and electrochemical tests. The nature of the passive film was also studied.
Paints containing zinc oxide and calcium carbonate (50/50) showed the best performance and a higher resistance in the salí spray test. Zinc oxide and calcium carbonate decreased film permeability and improved Steel passivation The passive film was composed by a ferric oxyhydroxide film whose pores became plugged by ferric phosphate
