Palumbo Gaetano, Dunikowski Dawid, Wirecka Roma, Mazur Tomasz, Lelek-Borkowska Urszula, Wawer Kinga, Banaś Jacek
Faculty of Foundry Engineering, Department of Chemistry and Corrosion of Metals, AGH University of Science and Technology, Mickiewicza St. 30, 30-059 Krakow, Poland.
Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza St. 30, 30-059 Kraków, Poland.
Materials (Basel). 2021 Sep 5;14(17):5084. doi: 10.3390/ma14175084.
The corrosion behavior of two silicon steels with the same chemical composition but different grains sizes (i.e., average grain area of 115.6 and 4265.9 µm) was investigated by metallographic microscope, gravimetric, electrochemical and surface analysis techniques. The gravimetric and electrochemical results showed that the corrosion rate increased with decreasing the grain size. The scanning electron microscopy/energy dispersive x-ray spectroscopy and X-ray photoelectron spectroscopyanalyses revealed formation of a more homogeneous and compact corrosion product layer on the coarse-grained steel compared to fine-grained material. The Volta potential analysis, carried out on both steels, revealed formation of micro-galvanic sites at the grain boundaries and triple junctions. The results indicated that the decrease in corrosion resistance in the fine-grained steel could be attributed to the higher density of grain boundaries (e.g., a higher number of active sites and defects) brought by the refinement. The higher density of active sites at grain boundaries promote the metal dissolution of the and decreased the stability of the corrosion product layerformed on the metal surface.
通过金相显微镜、重量法、电化学和表面分析技术研究了两种化学成分相同但晶粒尺寸不同（即平均晶粒面积分别为115.6和4265.9 µm）的硅钢的腐蚀行为。重量法和电化学结果表明，腐蚀速率随晶粒尺寸减小而增加。扫描电子显微镜/能量色散X射线光谱分析和X射线光电子能谱分析表明，与细晶粒材料相比，粗晶粒钢上形成了更均匀、致密的腐蚀产物层。对两种钢进行的伏打电位分析表明，在晶界和三相交界处形成了微电偶点。结果表明，细晶粒钢耐蚀性的降低可归因于细化带来的更高的晶界密度（例如，更多的活性位点和缺陷）。晶界处较高的活性位点密度促进了金属的溶解，并降低了在金属表面形成的腐蚀产物层的稳定性。
