【作者】 吴学庆；

【导师】 林建国；

【作者基本信息】 湘潭大学 ， 凝聚态物理， 2007， 硕士

【摘要】 本论文对Al-Ni-La, Al-Ni-La-Cu以及Al-Ni-La-Zr合金系的非晶形成能力进行了评估,采用单辊甩带法制备出了这三种合金体系的非晶薄带。采用示差热分析（DSC和DTA）对所制备的非晶合金的热力学行为进行了系统研究,探讨了添加元素Cu和Zr及其含量对Al-Ni-La基非晶的形成能力和热力学性能的影响,同时对Al88-xNi6La6Cux（X=0,2）非晶的晶化过程进行了研究。在此基础上,采用电化学方法研究了上述三种合金体系的腐蚀性能,分析了晶化过程对Al88-xNi6La6Cux（X=0,2）非晶腐蚀行为的影响,探讨了Cu和Zr元素及其含量对Al-Ni-La基非晶的腐蚀性能的影响及其机理。研究结果表明,使用MS法制备的Al₈₈Ni₆La₆非晶薄带,其玻璃转变温度（Tg）为224°C,该非晶的晶化过程为两步晶化,第一步晶化发生在233°C,其晶化相主要为面心立方的Al,第二步晶化发生在333°C,除面心立方的Al外,还有Al3Ni、Al11La3相析出。合金元素Cu和Zr的非晶形成能力和热力学性能会产生重要影响,在Al₈₈Ni₆La₆合金加入2 at.%Cu替代Al,使该非晶的玻璃转变不明显,晶化温度有所提高,晶化过程更加复杂,晶化产物增多。Zr的加入能提高Al86Ni9La5非晶的热稳定性和非晶形成能力,但Zr含量过高（如超过5at.%）,又会使该合金的非晶形成能力下降。晶化过程对非晶合金的腐蚀性能有重要影响,在0.01mol·L-1碱性NaCl溶液中,部分晶化的Al₈₈Ni₆La₆合金表现出更好的抗腐蚀性能,完全晶化的Al₈₈Ni₆La₆合金的抗腐蚀能力最差。而对于Al86Ni6La6Cu2非晶,部分晶化和完全晶化后,合金抗腐蚀性能均有所降低。合金化学成分对非晶的腐蚀性能有重要影响,在Al₈₈Ni₆La₆加入2at.%Cu,能促进钝化膜的形成,从而提高了Al₈₈Ni₆La₆非晶合金在0.01mol·L-1碱性NaCl溶液中的抗腐蚀能力。同时,晶化后,在Al₈₈Ni₆La₆和Al86Ni6La6Cu2晶基底上析出了组成不同的晶化相,这些相的电化学性质不同,从而造成两种合金的部分晶化后的腐蚀行为的差异。在Al-Ni-La体系中加入Zr元素,能改善该非晶合金的耐腐蚀性能,而且,随着Zr的含量的增加,该非晶在0.01mol·L-1碱性NaCl溶液中抗腐蚀性能不断增强。更多还原

【Abstract】 In this thesis, the amorphous forming ability （AFA） of Al-Ni-La, Al-Ni-La-Cu, and Al-Ni-La-Zr systems was evaluated, and the amorphous ribbons of these three alloys were prepared by melt-spinning （MS） method. The thermodynamics of the amorphous ribbons was investigated by the differential thermal analysis methods, i.e., DSC and DTA, and the effects of the additions of Cu and Zr and their content on the thermodynamics behavior and AFA of the Al-Ni-La system were discussed. The crystallization process of the Al88-xNi6La6Cux（X=0,2） was studied. Furthermore, the corrosion behaviors of the three alloy systems were studied by the electrochemistry method, focusing on the effects of crystallization and the addition elements of Cu and Zr on the corrosion behavior of Al-Ni-La based amorphous alloy. The results indicated that the amorphous ribbon of Al₈₈Ni₆La₆ exhibits a glass transition and two-step crystallization. The glass transition occurs at the temperature of 224°C, and the first step crystallization occurs at 233°C, and the second step crystallization occurs at 333°C, and the crystallization products are determined to be Al, Al3Ni and Al11La3 phases. The additions of Cu and Zr have obvious influence on the AFA and thermodynamic behaviors of Al-Ni-La system. Adding 2at.% Cu to the Al₈₈Ni₆La₆ can slightly promote the crystallization temperature of the amorphous alloy. The alloy with 2at.% Cu addition exhibits no obvious glass transition and more complicated crystallization process. Zr addition can also promote the AFA and thermal stability of Al86Ni9La5 amorphous alloy. However, when the content of Zr is over 5at.%, the AFA of the alloys will decrease. The corrosion behavior of the amorphous alloys is strongly dependent on the crystallization extent. Partially crystallized Al₈₈Ni₆La₆ alloy exhibits improved corrosion resistance in 0.01mol·L-1 NaCl alkaline solution in comparison to the fully amorphous alloy. While partially crystallized Al86Ni6La6Cu2 alloy exhibits lower corrosion resistance than that of the fully amorphous alloy. Full crystallization deteriorates the corrosion behavior of these two alloys. The composition has an important influence on the corrosion behavior of the amorphous alloy. The addition Cu to Al₈₈Ni₆La₆ can promote the formation of the passivation film on the surface of the alloy, resulting in the improvement of the corrosion resistance of the alloy, and by changing the crystallization products, Cu addition can change the corrosion behavior of the partially crystallized Al86Ni6La6. Zr addition to Al-Ni-La can improve the corrosion behavior of the alloy, and with the increase of Zr content, the corrosion resistance of the alloy increases in 0.01 mol·L-1NaCl alkaline solution.更多还原