A new pigment for smart anticorrosive coatings

C. DEYÁ; R. ROMAGNOLI; B. DEL AMO

Journal of Coatings Technology Research

Springer

Año: 2007 vol. 4 p. 167 - 175

1547-0091

The purpose of this paper was to evaluate the performance of a modified zeolitic rock as anticorrosive pigment in paints. A procedure to prepare the pigment was outline and its anticorrosive properties assessed following the electrochemical behaviour of a steel electrode in pigment suspension. In a second stage, alkyd paints were formulated employing different anticorrosive pigments: (1) 30% by volume (v/v) of the modified zeolitic rock, (2) a mixture of 10% (v/v) of zinc phosphate, and (3) a mixture of 10% (v/v) zinc phosphate plus 20% (v/v) of the modified zeolitic rock. In every case, percentages were referred to the total pigment content. Titanium dioxide, zinc oxide and barium sulphate were incorporated to complete the pigment formula. The PVC/CPVC (pigment volume concentration/critical pigment volume concentration) ratio was 0.8. The performance of the resulting anticorrosive paints was assessed by accelerated tests (salt spray and humidity chambers) and electrochemical (corrosion potential, ionic resistance and polarisation resistance) essays. It was demonstrated that the modified zeolitic rock is effective in protecting steel from corrosion when it is used in combination with zinc phosphate. There exits a synergism between the modified zeolitic rock and zinc phosphate that allows the zinc phosphate content in anticorrosive paints to be reduced.