The pH Detection of Phosphorous Dissolution from Phosphorous–deoxidized Copper in Simulated Pore Environment on Ant Nest Corrosion

Abstract

An electrochemical cell, which simulates the pore environment on ant nest corrosion, was developed for the pH detection of phosphorus dissolution from the phosphorous–deoxidized copper. The electrochemical cell was made of the transparent acrylic plate. The pore environment on ant nest corrosion was simulated by a gap between a wall surface of the cell and a metal working electrode (WE). The gap was filled with the gel containing the pH indicator. The electrochemical measurement can be performed by a three–electrode system because the edge of the gel was attached to the electrolyte solution in the cell only, namely, the pH changes due to the dissolution of metal WE can be detected by observation of color changes of the gel on the metal WE surface. The phosphorous–deoxidized copper and the oxygen-free copper were used as the WE to investigate pH changes related to the dissolution under potentiostatic polarization. In the present study, the methyl violet B was used as the pH indicator. The color of the gel on the oxygen-free copper did not change during the measurement. In the case of the phosphorous–deoxidized copper, the color change was observed on the gel clearly. In this case, the color of the gel corresponds to the pH in the range from 0.3 to 0.5.