The Corrosion Protection of Metals by Conductive Polymers. II. Pitting Corrosion
By Lu, Wei-Kang & Elsenbaumer, Ronald L.
William Andrew Publishing
1999
Abstract
Publisher Summary This chapter discusses the corrosion protection of metals by conductive polymers. The corrosion protection of carbon steel by conductive polymers in an acidic environment proves to be efficient but cannot reduce much of the pitting trend. In the experiment described in the chapter, the Americhem formulated polyaniline (ACl) demonstrated very strong anticorrosion properties in both general corrosion and local corrosion in 3.5% NaCl. On the contrary, most of the commercially available materials lack protection efficiency under the same experimental condition. Considerable pitting current in a drilled hole can be reduced by the application of AC1, and it is technologically important because the easy processing and coating procedures lead to satisfactory mechanical strength. However, the reformulation of polyaniline (PANI) mixed with binder shows that the pitting behaviors of ferrous and nonferrous alloys influenced by intrinsically conductive polymers can be studied by the electrochemical noise (ECN), cathodic protection (CP), and electrochemical impedance spectroscopy (EIS) techniques, which provide a better understanding of the corrosion and pitting mechanisms. Preliminary inert-gas-aeration results indicate that oxygen is not a factor in the early immersion period but becomes important when the protection mode moves to anodic protection.