Protection of zinc with pyrophosphate films

B.A.LÓPEZ DE MISHIMA; C. P. DE PAULI,; H.T.MISHIMA; M.INES SANCHEZ DE PINTO

BULLETIN OF ELECTROCHEMISTRY

CENTRAL ELECTROCHEM RES INST

Lugar: Karaikudi; Año: 1991 vol. 7 p. 402 - 406

0256-1654

The electrochemical behaviour of zinc in pyrophosphate in acetic-acetate buffer solutions of pH 4.7 shows that the value of corrosion potential, corrosion current and anodic (ba) and cathodic (bc) Tafel constant do not depend on pyrophosphate concentration and electrode rotation rate W. The chemical formed films are more homogeneous, compact and more protective than films obtained by anodic polarization. The analysis of potentiostatic transients is in accordance with a three dimensional growth showing an overlap effect.