摘要
镍镀层作为最重要的防护装饰性镀层之一，广泛应用在人们日常生活中密切接触到的金属表面。然而镍镀层在与人体的皮肤长期接触后易被汗液腐蚀，产生镍释放现象，对人体造成过敏等危害。随着社会发展，人们与金属的接触将愈发频繁。出于安全的考量，国际上出台了相关规定限制与人体密切接触的金属材料的镍释放量。为了达到这一规定，减少甚至消除镀层的镍释放量，尤其是镍替代镀层的研究工作有十分重要的工程应用价值和科学意义。
为解决镍镀层的镍释放问题，本文创新性地提出以Al-Mn合金镀层作为镍替代镀层，镀层中完全不含镍元素，从根源上消除镍释放的危害。本文采用离子液体电沉积技术制备具有不同晶体结构的Al-Mn合金镀层，研究了钝化处理、光亮镀对镀层性能的影响，通过照相法对比镀层的镜面光亮程度，采用粗糙度仪、光泽度仪、电子显微镜分析镀层的宏观和微观特征，采用显微硬度计分析镀层硬度，通过静态浸泡腐蚀试验和电化学测试研究镀层在人工汗液中的耐蚀性。
研究结果表明：在AlCl3-EMIC-MnCl2离子液体中电沉积得到的晶态Al-Mn 合金镀层均匀致密、与基体结合情况良好。镀层在人工汗液中发生不均匀的全面腐蚀，平均腐蚀速率为0.0056 mm/a，约为纯Al镀层的三分之一，依据金属耐蚀性的十级标准，属于3级“很耐蚀材料”。
本文首次提出了Al-Mn合金镀层在人工汗液中的腐蚀机理：人工汗液中的氯离子破坏镀层表面的钝化膜，
镀层被腐蚀，释放金属离子，乳酸与金属离子形成络合物，随着溶液pH的变化转变为沉淀，促进金属的溶解。腐蚀产物主要为Al(OH)3，Mn很少被腐蚀。
无铬钝化处理可以降低镀层的腐蚀电流至未钝化镀层腐蚀电流的三分之一，提高镀层的耐腐蚀性能。钝化膜存在裂纹，镀层的装饰性没有提高。通过在镀液中添加光亮剂，可以得到晶粒细小、晶面取向一致的镜面光亮镀层，镀层装饰性得到提高，与未添加光亮剂的镀层相比耐腐蚀等级提高一级，脆性增大。
在AlCl3-EMIC-MnCl2离子液体中电沉积得到的非晶态Al-Mn合金镀层镜面光亮效果好，硬度达6.72±0.41 GPa，高于光亮镍镀层。在人工汗液中发生全面的均匀腐蚀，平均腐蚀速率为0.0024 mm/a，属于2级“很耐蚀材料”。镀层在人工汗液中的腐蚀电流密度为9.6×10-7 A/cm2，与光亮镍镀层相近，腐蚀电位为-0.99 V vs.SCE，对腐蚀电位比镍镀层更负、比非晶态Al-Mn镀层更正的基体起牺牲阳极保护作用。
关键词：人工汗液；镍释放；Al-Mn合金镀层；离子液体；电沉积；耐蚀性
飞词组
Abstract
Nickel coating, one of the most important protective decorative coatings, is widely ud on metals su
rfaces that in clo contact with hunman in daily life. However, after prolonged contact with the human skin, the nickel coating would be easily corroded by human sweat, causing nickel relea and allergy to the human body. With the development of society, contact between human and metals will become more frequent. For safety, international regulations have been propod to limit the relea of nickel from metal materials that are in clo contact with the human body. In order to satisfy this regulation, reducing or even eliminating the amount of nickel relead from the coatings, especially the rearch work on replacement for nickel coating, has great significance in engineering application and scientific rearch.
In order to solve the problems caud by nickel relead from nickel coating, this paper innovatively propod to u the aluminum-mangane alloy coating as a replacement of nickel coating. The coating is completely free of nickel elements, fundamentally eliminating the harm of nickel relea. In this paper, electrodeposition from ionic liquid was ud to prepare aluminum-mangane alloy coatings with different crystal structures. The effect of passivation treatment and brightener on the properties of the coatings were studied. Photographic method was ud to compare the mirror effect on the surface of the coatings. The roughness tester, the glossiness tester and the electron microscope were ud to analyze the macro and micro characteristics of the coatings. The micro har
dness tester was ud to analyze the hardness of the coatings. And the corrosion resistance of the coatings in artificial sweat was studied by static immersion corrosion test and electrochemical test.
Results showed that the crystalline aluminum-mangane coating electrodeposited from AlCl3-EMIC-MnCl2 ionic liquid was uniform and den, and had good adhesion with the substrate. The coating had uneven general corrosion in artificial sweat. The average corrosion rate was 0.0056 mm/a, which was about one-third of the pure aluminum coating. According to the ten-level standard of metal corrosion resistance, it was a Level 3 ‘very corrosion-resistant material’.
孔侍中帖In this paper, the corrosion mechanism of aluminum-mangane alloy coating in artificial sweat was propod for the first time. Chloride ion in artificial sweat destroyed the passivation film on the surface of the coating. Then the coating was corroded and
浙江大学硕士学位论文
metal ions were relead. The metal ions formed a complex with lactic acid and subquently turned into a precipitate as the pH of the solution changed, accelerating the dissolution of metals. The corrosion products were mainly Al(OH)3, while Mn was rarely corroded.
Chromium-free passivation treatment could reduce the corrosion current of the coating to one-third of that of the unpassivated coating, and improve the corrosion resistance of the coating. There were cracks in the passivation film, and the decorative property of the coating was not improved. A mirror bright coating with fine crystal grains in the same orientation was obtained after adding brightener into the electrolyte. The decorative property of the coating was improved. Compared with the coating without brightener, the corrosion resistance level was improved by one level and the brittleness was incread.
The amorphous aluminum-mangane alloy coating obtained by electrodeposition in AlCl3-EMIC-MnCl2 ionic liquid had a good mirror effect. Hardness of the coating was 6.72±0.41 GPa, which is higher than Ni coating. General corrosion occurred in artificial sweat. The average corrosion rate was 0.0024 mm/a, which was a Level 2 ‘very corrosion-resistant material’. The corrosion current density of the coating in artificial sweat was 9.6×10-7 A/cm2, which was similar to the bright nickel coating. The corrosion potential was -0.99 V vs. SCE. The coating would rve as a sacrificial anode protection to the substrate who corrosion potential is more negative than nickel coating and more positive than amorphous aluminum-mangane alloy coating.
Key words: Artificial sweat, Nickel relea, Al-Mn alloy coating, Ionic liquid, Electrodeposition, Corros
ion resistance
IV
目录
摘要............................................................................................................................. I II 第一章绪论. (1)
1.1 引言 (1)
1.2 镍镀层及其汗液腐蚀 (2)
1.2.1 镍镀层的应用 (2)
1.2.2 镍镀层的汗液腐蚀及镍释放 (2)
1.2.3 镍镀层的人工汗液腐蚀速率及机理 (3)
1.3 镍替代镀层的研究现状 (4)
1.4 Al-Mn合金镀层的特点 (6)
1.5 Al-Mn合金镀层的电沉积制备方法 (7)
1.6 离子液体电沉积Al-Mn合金镀层 (7)
1.6.1 离子液体的简介 (7)
1.6.2 AlCl3-EMIC离子液体的简介 (9)
1.6.3 AlCl3-EMIC离子液体的应用 (11)
1.6.4 AlCl3-EMIC离子液体电沉积Al-Mn合金镀层 (11)
1.7 Al-Mn合金镀层耐蚀性影响因素 (12)
1.7.1 锰含量对Al-Mn合金镀层结构的影响 (12)
1.7.2 镀层结构对Al-Mn合金镀层耐蚀性的影响 (14)
1.8 课题提出及研究内容 (15)
第二章实验方法 (17)
2.1 实验材料与试剂 (17)
2.2 实验仪器设备 (18)书信作文格式
2.3 离子液体的配制 (18)
2.4 前处理工艺 (19)
2.4.1 铜基体的前处理 (19)
2.4.2其他电极材料的前处理 (19)
2.5 离子液体电沉积Al-Mn合金镀层 (20)
2.6 后处理工艺 (21)
2.7 测试与表征 (22)
福尔摩斯探案集读后感2.7.1 宏观形貌 (22)
2.7.2 微观形貌及成分分析 (23)
2.7.3 物相结构分析 (23)
2.7.4 显微努氏硬度分析 (24)
2.7.5 脆性分析 (24)
风潇
2.7.6 电化学测试 (24)
2.7.7 静态全浸试验 (25)
第三章晶态Al-Mn合金镀层的耐人工汗液腐蚀性能 (29)
3.1 引言 (29)
3.2 晶态Al-Mn合金镀层的制备 (29)
3.2.1 形貌与成分 (29)
3.2.2 物相结构 (31)
梦到姥姥3.2.3 硬度 (34)
3.3 晶态Al-Mn合金镀层的耐人工汗液腐蚀性能 (34)
3.3.1 静态浸泡试验 (34)
3.3.2 电化学测试 (40)
3.4 腐蚀机理探究 (43)
3.5 本章小结 (45)
第四章后处理及光亮镀对晶态Al-Mn合金镀层耐人工汗液腐蚀性能的影响.47 4.1 引言 (47)
4.2 无铬钝化处理及镀层耐人工汗液腐蚀性能研究 (47)
4.2.1 形貌及成分 (48)
4.2.2 耐人工汗液腐蚀性能 (49)
4.3 光亮剂浓度对镀层的影响 (51)
4.3.1 宏观形貌 (51)
4.3.2 微观形貌及成分 (53)
4.3.3 物相结构 (53)
4.3.4 光亮晶态Al-Mn合金镀层耐人工汗液腐蚀性能 (56)
4.3.5 硬度及脆性 (59)
4.4 本章小结 (60)
最简单的做奶茶的方法第五章非晶态Al-Mn合金镀层的耐人工汗液腐蚀性能 (61)
5.1 引言 (61)月经期间吃什么水果
5.2 非晶态Al-Mn合金镀层的制备 (61)
