報告人：汪裕洲 博士
報告人簡介：汪裕洲博士于2022年在浙江大學取得工學博士學位，目前在香港理工大學建築與環境學院土木工程系擔任博士後研究員。汪裕洲博士主要緻力于鋼結構和鋼筋混凝土結構中的鋼材腐蝕問題的研究，主要研究方向包括：1) 先進耐候鋼在海洋大氣環境中的應用；2) 耐腐蝕鋼筋-海水海砂混凝土體系腐蝕行為；3) 混凝土内的鏽蝕産物反應-傳輸模型及其對混凝土鏽裂的影響。
報告人單位：香港理工大學
時間：2024年10月12日（星期六）10:00-11:00
地點：大結構會議室209
線上鍊接：騰訊會議678-238-216
報告摘要：
Weathering steel, developed in 1930s, was a low-alloyed steel with high cost-effectiveness and good corrosion resistance. However, conventional weathering steel cannot be applied to marine environment since the formation of protective rust layer on its surface is inhibited by the chloride ions. In this study, rare earth (RE) element was added to weathering steel to improve its corrosion resistance. Both the corrosion initiation and long-term corrosion performance in different chloride concentration were investigated by multifarious analytical technique, such as exposure test, electrochemical measurement, 3d laser scanning microscope, scanning electron microscope/energy dispersive spectroscopy (SEM/EDS) and Raman spectroscopy. Results show that although RE elements can refine grains and modify inclusions, the corrosion initiation of weathering steel with RE addition cannot be inhibited since the dissolution of grains with higher corrosion activity contributes to most of the weight loss at this stage. Besides, the long-term corrosion performance of weathering steel with RE addition, which can be attributed to its rust layer with compact and dense structures. Considering that the corrosion initiation stage is such a short period compared to the steady-corrosion state during weathering steel’s service life, it can be concluded that the RE addition can improve the corrosion resistance of weathering steel, especially in marine atmospheric environments.
耐候鋼是一種20世紀30年代開發的，具有高性價比和較好耐蝕性的低合金鋼。然而，由于表面保護性鏽層的形成受到氯離子的阻礙，傳統耐候鋼不能被用于海洋環境。為了改善耐候鋼的耐腐蝕性，本研究向耐候鋼中加入了稀土元素。在不同氯濃度環境下，采用多種分析技術（暴露試驗，電化學測試，三維激光掃描顯微鏡，掃描電鏡/能譜，拉曼光譜）研究了鋼材的腐蝕初始和長期腐蝕行為。結果表明，盡管稀土元素能夠細化晶粒并改善夾雜物，但并不能遏制耐候鋼腐蝕的發生，這是因為具有更高腐蝕活性的晶粒溶解是該階段質量損失的主要來源。此外，稀土耐候鋼表面能形成緻密的鏽層，使其具有更好的長期耐腐蝕性。考慮到相比于耐候鋼服役壽命中的穩定腐蝕階段，腐蝕初始階段隻占據極短的一段周期，故可以得到結論：向耐候鋼内添加稀土元素整體上提高了其耐腐蝕性，尤其是在海洋大氣環境中。
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