A DC electrochemical method for studying the inhibition of metal corrosion by chromate-containing paint
By Spellane, Peter
Published in Progress in Organic Coatings
1999
Abstract
A DC potentiodynamic curve method is used to observe the effect of a pigmented organic coating on the passivity of a metal substrate. In this method, a painted metal coupon, which is scribed to expose metal, functions as the working electrode (WE) of an electrochemical cell; the cell includes a graphite bar counter electrode (CE), a saturated calomel reference electrode (RE), and aqueous electrolyte. Increasingly oxidizing potentials are imposed on the WE by a potentiostat, and current between the WE and CE is measured at each applied potential. The resulting current–voltage (I–V) curve indicates effects of the coating on the metal's open circuit potential and passivity. The passivating effect of a chromate-containing primer paint on mild steel is demonstrated and compared to the passivity of 316 stainless steel.