内生锆基非晶复合材料在不同溶液中的腐蚀行为

发布时间：2018-04-09 14:42

本文选题：非晶合金　切入点：非晶复合材料　出处：《太原理工大学》2016年硕士论文

【摘要】：块体非晶合金的出现打破了一直以来工程建设中以晶体材料为主体的格局。由于其结构的特殊性,致使无数研究者将注意力集中在块体非晶合金制备、性能等的探索上。迄今为止,块体非晶合金的制备已经可以通过很多方法获得,其在尺寸上也有了极大的突破,目前报道的Pd42.5Cu30Ni7.5P20非晶合金的最大尺寸可达到80 mm。由于非晶合金具有传统晶体材料所不具有的特殊结构,内部不存在位错、界面等结构缺陷,致使非晶合金拥有晶态合金所无法达到的优异性能,如高强度、高硬度、超高抗腐蚀能力以及优异的磁学性能等。这些优异性能的呈现使非晶合金成为了当今最具潜力的工程材料。尽管非晶合金具有很多优异的性能,但其在室温下的脆性断裂导致其在许多领域的应用受到了约束。为了克服这一缺点,提高非晶合金的室温韧性。本文通过向非晶合金中添加第二相制取两相共存的非晶复合材料,将强度和塑性进行完美结合,从而扩大非晶合金的应用范围。本文通过铜模吸铸法获得了强度高且具有较好室温塑性的非晶复合材料Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0,采用X射线衍射仪(XRD)和扫描电子显微仪(SEM)等技术手段对该非晶复合材料的结构进行分析确认。通过电化学测试方法,如动电位极化曲线、交流阻抗谱等对非晶试样在不同环境下的抗腐蚀能力进行分析讨论,同时还使用化学浸泡实验对腐蚀结果进行进一步的确认。对于非晶复合材料腐蚀后的表面破坏情况可以通过SEM检测方法进行观察,结合以上分析手段对该非晶复合材料的腐蚀机理进行归纳总结。本文通过将Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0非晶复合材料放入不同浓度的NaCl溶液中进行抗腐蚀行为的研究,结果发现该非晶合金在不同含量的NaCl溶液中抵抗腐蚀的能力与NaCl的增加量不呈对应关系,而是呈抛物线趋势。在中间值5%NaCl含量的时候,非晶复合材料的抗腐蚀能力最差,而在最低浓度1%和最高浓度15%时的抗腐蚀能力表现最优异。通过对溶液中电介质的分析可得出,该非晶复合材料在NaCl溶液中的抗腐蚀能力不仅与溶液中氧的含量有关,还与溶液中氯离子的浓度有关。比较pH值不同的情况下该锆基非晶复合材料的抗腐蚀行为,结果发现在NaOH溶液中材料的抗腐蚀分析结果出现了分歧,即极化曲线判断结果与表面腐蚀破坏程度不一致。并且可以发现氯离子不仅对晶体材料具有很强侵蚀能力,对非晶合金及其复合材料的腐蚀也有很强的破坏能力。从含氯离子溶液中的表面腐蚀形貌可以观察到,和晶态树枝晶的抗腐蚀能力相比,非晶基体的抗腐蚀能力较差,在合金中其将优先发生腐蚀溶解,这一差异的出现主要与Zr和Be等金属元素在非晶基体和树枝晶上的分布有关。
[Abstract]:The appearance of bulk amorphous alloys has broken the pattern of crystal materials as the main body in engineering construction.Due to its special structure, numerous researchers have focused on the preparation and properties of bulk amorphous alloys.Up to now, the preparation of bulk amorphous alloys can be obtained by many methods, and the size of bulk amorphous alloys has also made a great breakthrough. The maximum size of Pd42.5Cu30Ni7.5P20 amorphous alloys reported at present can reach 80 mm.Because the amorphous alloy has the special structure which the traditional crystal material does not have, the internal does not have the dislocation, the interface and so on structural defect, causes the amorphous alloy to have the outstanding performance which the crystalline alloy cannot achieve, such as the high strength, the high hardness,High corrosion resistance and excellent magnetic properties.These excellent properties make amorphous alloys the most promising engineering materials.Although amorphous alloys have many excellent properties, their brittle fracture at room temperature restricts their applications in many fields.In order to overcome this shortcoming, the room temperature toughness of amorphous alloy is improved.In this paper, two phase coexisting amorphous composites are prepared by adding the second phase to the amorphous alloy, and the strength and plasticity are combined perfectly, thus expanding the application range of the amorphous alloy.The amorphous composite Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0 with high strength and good room temperature plasticity was obtained by copper mould suction casting. The structure of the amorphous composite was analyzed and confirmed by means of X-ray diffractometer (XRD) and scanning electron microscopy (SEM).The corrosion resistance of amorphous samples in different environments was analyzed and discussed by electrochemical methods such as potentiodynamic polarization curve and impedance spectroscopy. The corrosion results were confirmed by chemical immersion test.The surface failure of amorphous composites after corrosion can be observed by means of SEM, and the corrosion mechanism of amorphous composites can be summarized by the above analysis methods.In this paper, the corrosion resistance of Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0 amorphous composites in NaCl solution with different concentration was studied. It was found that the ability of the amorphous alloy to resist corrosion in different content of NaCl solution did not correspond to the increase of NaCl.But a parabolic trend.The corrosion resistance of amorphous composites is the worst when the content of 5%NaCl is intermediate, but the corrosion resistance is the best at the lowest concentration of 1% and the highest concentration of 15.Through the analysis of the dielectric in the solution, it can be concluded that the corrosion resistance of the amorphous composite in NaCl solution is related not only to the content of oxygen in the solution, but also to the concentration of chloride ion in the solution.By comparing the corrosion resistance of the zirconium matrix amorphous composites with different pH values, it is found that the results of corrosion resistance analysis in NaOH solution are different, that is, the results of polarization curves are not consistent with the corrosion failure degree of the surface.It can also be found that chloride ion not only has a strong corrosion ability to the crystal material but also to the amorphous alloy and its composite material.From the surface corrosion morphology of chlorinated solution, it can be seen that compared with the corrosion resistance of crystalline dendrite, the corrosion resistance of amorphous matrix is poor, and the corrosion dissolution of amorphous matrix will occur preferentially in the alloy.This difference is mainly related to the distribution of Zr and be on amorphous substrates and dendrites.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG139.8

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