Aluminium triphosphate pigments for anticorrosive paints

M. DEYÁ; V. VETERE; R. ROMAGNOLI; B. DEL AMO

Santiago, Chile

Congreso; LATINCORR 2003. 5to Congreso de Corrosión de la NACE Región Latinoamérica y 8vo congreso Iberoamericano de Corrosión y Protección; 2003

The objective of this worl was to study the efficiency of two anticorrosive pigments containing aluminium tripolyphosphate. Pigments were analysed by current analytical techniques. The anticorrosive properties of the selected pigments were evaluated following the electrochemical behaviour of a steel electrode in pigments susppensions. In a second stage, solvent borne paints with 10 and 30% v/v of the pigment and PVC/CPVC (pigment volume concentration /critical pigment volume concentration) ratio 0.8 were formulated. Three resins were chosen: an alkyd, an epoxy and a vinyl one. The performance of the resulting anticorrosive paints was assessed by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential, ionic resistance and polarisation resistance). The anticorrosive performance of the tested paints was closely related with pigment composition. The nature of the resin was also of importance; in this sense, epoxy paitns showed the best anticorrosive performance. Good correlation has been obtained between accelerated and electrochemical tests.