| 摘要: |
| 为提高Ti2AlNb合金的实际使用温度,采用加弧辉光等离子渗镀技术在合金表面制备渗镀Al层,研究渗镀Al层在750℃下涂盐Na2SO4和Na2SO4+25%NaCl的热腐蚀行为。同时利用扫描电子显微镜(SEM)、能谱仪(EDS)对腐蚀产物的形貌进行观察,并结合X射线衍射对相组成进行分析。结果表明:渗镀Al层组织均匀致密,与基体结合良好。涂层可分为明显的3个区域:最外层Al2O3薄膜、次表层纯Al沉积层和内层Al-Ti-Nb扩散层。扩散层主要包括Al3Ti﹑Al3Nb和AlNb2等相。渗镀Al层试样在750℃的Na2SO4盐热腐蚀100 h后,仅增重约2 mg/cm2,表现出良好的抗热腐蚀性能;而在Na2SO4+25%NaCl混合盐中,试样则先增重后逐渐减重,整个涂层出现明显开裂和剥落,其原因是Cl-的渗入使表面形成的Al2O3膜被破坏,进而加速消耗涂层中的Al。 |
| 关键词: 热腐蚀 NaCl盐 渗镀Al层 Ti2AlNb合金 |
| DOI：10.11933/j.issn.1007-9289.2016.03.006 |
| 分类号: |
| 基金项目:国家自然科学基金(51474131);南京航空航天大学博士学位论文创新与创优基金(BCXJ14-11);江苏高校优势学科建设工程资助项目(PAPD) |
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| Effects of NaCl Salt on Hot Corrosion Behaviors of Aluminized Layer Prepared on Ti2AlNb Alloy |
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REN Bei-lei, MIAO Qiang, LIANG Wen-ping, XIA Jin-jiao, HU Rong-yao
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Collage of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106
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| Abstract: |
| To improve the actual temperature of Ti2AlNb alloy, an aluminized layer was prepared on the surface by arc-added glow discharge plasma surface alloying technique. Hot corrosion behaviors of the aluminized layer in Na2SO4 and Na2SO4+25%NaCl salt at 750℃ were investigated. Morphologies and phase structure of corrosion products were analyzed by scanning electron microscope, energy dispersive spectromete and X-ray diffraction. The results show that the aluminized layer is dense and is tightly adhered to the substrate. The microstructure of the aluminized layer is divided into three distinguished areas: the outer thin Al2O3 layer, the intermediate layer of pure Al deposition, and the inner Al-Ti-Nb mutual diffusion layer. The diffusion layer is composed of Al3Ti, Al3Nb and AlNb2 phases. The mass of the aluminized layer only increases about 2 mg/cm2 when corroded in a pure Na2SO4 environment at 750℃ after 100 h, which shows good hot corrosion resistance. The mass first increases and then decreases when corroded in Na2SO4+25%NaCl salt and obvious spalling occurred in the chlorate containing molten salt. The reason is that the infiltration of Cl- destroys the Al2O3 film on the surface, and then accelerates the consumption of Al in the aluminized layer. |
| Key words: hot corrosion NaCl salt aluminized layer Ti2AlNb alloy |
