• The dynamic influence of temperature variations on the development of TLC is systematically investigated. • The proportion of macro-cell current and micro-cell current in TLC under different temperatures is quantified. • The interplay between droplet condensation and corrosion development on TLC processes is described. This systematic study explores the effects of temperature gradients at top surface on top-of-the-line corrosion (TLC) of pipeline steel X65 under conditions of a constant high-temperature CO 2 -saturated aqueous phase at the bottom. Localized TLC behaviours were comprehensively analysed through wire beam electrode (WBE) techniques in combination with local electrochemical measurements. Results demonstrate significant differences in the impacts of micro-cell and macro-cell currents on the corrosion process under varying temperature conditions. At low top surface temperatures, uniform corrosion dominates, primarily driven by micro-cell currents. Conversely, increasing top surface temperature promotes localized corrosion and the dominance of macro-cell currents. Furthermore, corrosion products exhibit significant regional variations beneath droplet, highlighting a non-uniform nature of corrosion processes. These findings elucidate the temperature-dependent mechanisms of TLC and provide critical insights into the TLC process of pipeline steel.
Wang et al. (Sun,) studied this question.