The corrosion behavior of the inner surface of commercially available pineapple cans (unlacquered tinplate cans)were investigated using accelerated pack test and electrochemical measurements. In the accelerated pack test, the tin concentration in the contents increased over time. The increase was greater as the tin-iron alloy layer became exposed, and the internal pressure also increased. Electrochemical measurements showed that the corrosion potentials of tin, iron, and the tin-iron alloy layer were increasingly noble, in that order, supporting the corrosion behavior of tin in the accelerated pack test. Based on these results, it is suggested that corrosion of the inner surface of the can is represented by five stages.
In this study, the mechanism of pH decrease in an electrolytic solution containing ammonium thiocyanate (NH4SCN) during electrolytic hydrogen charging was elucidated. The pH of an electrolytic solution containing NH4SCN decreases during hydrogen charging, which is caused by the formation of sulfate ions from the oxidative decomposition reaction of thiocyanate ions (SCN-) on a Ti-Pt anode. The suppression of pH decrease using a cation-exchange-resin-coated IrO2 electrode, which has a lower probability of decomposing NH4SCN than a Ti-Pt anode, was investigated to develop a method for controlling the pH decrease in an electrolytic solution containing NH4SCN during electrolytic hydrogen charging. Specifically, the use of a cation-exchange-resin-coated IrO2 electrode suppresses the decrease in the pH of the electrolytic solution. [doi:10.2320/matertrans.MT-C2025001]
