Improvement of anticorrosive performance of phosphate-based alkyd paints with suitable additives

G. BLUSTEIN; M. C. DEYA; R. ROMAGNOLI; A. R. DI SARLI; B. DEL AMO

JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH

SPRINGER.COM

Año: 2011 vol. 8 p. 171 - 181

1935-3804

The purpose of this investigation wasfocused on reducing the content of zinc phosphate inanticorrosive paints by means of the incorporation oflow quantities of selected soluble corrosion inhibitors.The article describes the anticorrosive behavior ofalkyd paints containing reduced levels of zinc phosphate,zinc oxide, and some soluble compounds used asadditives (e.g., sodium polyphosphate, sodium phosphate,and sodium benzoate). Anticorrosive solventbornealkyd paints were formulated with a zincphosphate content of 10% by volume (v/v) with respectto the total pigment concentration. In all cases, thePVC/CPVC (pigment volume concentration/criticalpigment volume concentration) ratio was 0.8. Experimentalpaints, applied on sandblasted SAE 1010panels, were evaluated by accelerated tests (salt spraycabinet) and electrochemical measurements (electrochemicalimpedance spectroscopy, EIS). The resultsshow that the additions of small amounts of solublecorrosion inhibitors to low content zinc phosphatepaint formulations enhance their performance in a veryremarkable way. Perhaps, the most outstanding featureis that the employment of soluble additives allowed thereduction of the zinc phosphate content with concomitantsavings.