Corrosion inhibition of copper in ferric chloride solutions with organic inhibitors

Abstract

Abstract Ferric chloride (FeCl 3 ) has widespread use as an etchant in the PCB industry and for photochemical machining. Although the corrosion process of copper in FeCl 3 is well known, the use of organic inhibitors of copper corrosion in FeCl 3 solutions has not been reported. Such inhibition may allow microfabrication of special PCB designs and electrochemical sensors. Here, we investigate the inhibition of copper corrosion by FeCl 3 (0.10 or 2.46 M) solutions with organic inhibitors. The most promising inhibitors are identified, investigated in 0.01 M FeCl 3 solution using electrochemical techniques at different temperatures and exposure times, and the modified surfaces of copper are characterized by a variety of techniques in order to determine the inhibition mechanism. 5-methyl-1H-benzotriazole (MBTA, 65 mM) and 1H-benzotriazole (BTA, 65 mM) are found to be the most attractive inhibitors, with inhibition efficiencies between 96.5% and 99.5% at room temperature, depending on the exposure time and the measurement technique.