研究了在含三角褐指藻的人工海水（含藻海水）中，循环光照12 h/黑暗12 h、光照、黑暗条件下船用Q235碳钢的腐蚀行为，以及腐蚀7 d后的电化学性能，并与无藻海水中的进行了对比，分析了三角褐指藻的生命活动对碳钢腐蚀行为的影响。结果表明：在含藻海水中，光照条件下，氧气的去极化反应占主导，碳钢表面发生点蚀，腐蚀产物主要为γ-FeOOH；黑暗条件下，CO₂腐蚀导致碳钢表面发生均匀腐蚀，腐蚀产物主要为FeCO₃；循环光照12 h/黑暗12 h条件下两种腐蚀方式共同作用，腐蚀产物由γ-FeOOH、Fe₃O₄和FeCO₃组成；与在无藻海水中浸泡7 d后的相比，在含藻海水中，不同光照条件下浸泡7 d后，碳钢的电荷转移电阻减小，自腐蚀电流密度增大。

The corrosion behavior of marine Q235 carbon steel in artificial seawater with Phaeodactylum tricornutum (seawater with algae) under cyclic light 12 h/dark 12 h, continuous light, and continuous dark conditions, and the electrochemistry performance after corrosion for 7 days were studied, compared with that in the seawater without algae. The effects of the life activity of Phaeodactylum tricornutum on the corrosion behavior of carbon steel were analyzed. The results show that in the seawater with algae, the depolarization reaction of oxygen was dominant under continuous light condition, resulting in pitting on the carbon steel surface, and the corrosion product was γ-FeOOH. Under the condition of continuous dark, carbon dioxide corrosion caused uniform corrosion of Q235 carbon steel surface, and the corrosion product was FeCO₃. The two types of corrosion methods were combined under the cyclic light 12 h/dark 12 h condition, and the corrosion products consisted of γ-FeOOH, Fe₃O₄ and FeCO₃. In the seawater with algae, the charge transfer resistance of carbon steel decreased and the self-corrosion current density increased after immersion under different light conditions for 7 days, compared with that in the seawater without algae.