Jin Kwang-Hyeok, Oh Min-Suk
Division of Advanced Materials Engineering, Research Center of Advanced Material Development, Jeonbuk National University, Jeonju 54896, Republic of Korea.
Materials (Basel). 2023 Aug 25;16(17):5827. doi: 10.3390/ma16175827.
Hot-dip Al-Si alloy coatings with excellent resistance to corrosion and high-temperature oxidation have emerged as promising lightweight substitutes for conventional corrosion-resistant coatings. The introduction of Mg can be an effective strategy for enhancing the sacrificial protection capability of Al-Si coatings. In this study, the effects of Mg addition on the morphology, electrochemical behavior, and mechanical properties of Al-Si coatings were investigated, along with the Mg-content optimization of the coating layer. Adding Mg promoted the formation of finely distributed eutectic intermetallic phases, such as Al/MgSi and the primary MgSi phase. Notably, the MgSi phase coarsened significantly when ≥15 wt.% of Mg was added. In addition, an AlMg intermetallic compound was observed in coating layers containing >20 wt.% of Mg, reducing the adhesion of the coating layers. Samples containing 5-10 wt.% of Mg exhibited excellent corrosion resistance (owing to a uniform distribution of the fine eutectic Al/MgSi phase and the formation of stable corrosion products), whereas those containing 20 wt.% of Mg exhibited unremarkable corrosion resistance (owing to the formation of an AlMg phase that is susceptible to intergranular corrosion).
具有优异耐腐蚀和高温氧化性能的热浸镀铝硅合金涂层已成为传统耐腐蚀涂层有前景的轻质替代品。添加镁可能是增强铝硅涂层牺牲保护能力的有效策略。本研究考察了添加镁对铝硅涂层的形貌、电化学行为和力学性能的影响，以及涂层的镁含量优化。添加镁促进了细小分布的共晶金属间相的形成，如Al/MgSi和初生MgSi相。值得注意的是，当添加≥15 wt.%的镁时，MgSi相显著粗化。此外，在含>20 wt.%镁的涂层中观察到一种AlMg金属间化合物，降低了涂层的附着力。含5-10 wt.%镁的样品表现出优异的耐腐蚀性（由于细共晶Al/MgSi相的均匀分布和稳定腐蚀产物的形成），而含20 wt.%镁的样品表现出不显著的耐腐蚀性（由于形成了易发生晶间腐蚀的AlMg相）。
