Abstract
The research described in this paper was carried out with the objective of establishing any correlation between coating performance and the results of cathodic disbondment testing. Experiments were carried out using 13 coatings. Nine samples of each coating were studied in a total of 117 experiments. Fifty-eight (58) samples were placed in an environmental chamber at a constant temperature of 65°C, and 59 samples were placed in a different environmental chamber at a temperature that varied between 5 and 65°C. The initial temperature of this environmental chamber was 5°C and, after 30 days, the temperature was raised to 15°C. The temperature in the fluctuating chamber was increased by 10°C after every 30 days. Data were obtained from cathodic current, solution pH, and potential during the experiments and cathodic disbondment after the experiments. Based on the experiments carried out over a period of 14 months using 13 different pipeline coatings, in this investigation it was found that characteristic current spikes occurred whenever blisters are formed on the coatings.
