电沉积Zn-Fe-RE三元合金工艺的研究

【作者】 陈阵；

【导师】 张英杰；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2004， 硕士

【摘要】 本论文研究了硫酸盐体系和氯化物体系电沉积Zn-Fe-Re三元合金镀层的工艺和机理，并最终在氯化物体系下选择LaCl₃电沉积出Zn-Fe-La三元合金镀层。主要具体工作包括以下几个方面： 通过250ml Hull槽实验和150ml矩形槽正交实验，确定了硫酸盐体系中稀土盐作为添加剂改变Zn-Fe合金镀层性能的电沉积工艺，其工艺条件为：FeSO₄·7H₂O 80～120g／L、ZnSO₄·7H₂O 30～50g／L、Ce₃（SO4）2 0.6～1.5g／L，（NH₄）₂SO₄ 50～80g／L、C₆H₈O₇·H₂O 10～20g／L、H₃BO₃ 5～15g／L、抗坏血酸1～3g／L、添加剂适量、pH值2～4、施镀时间10min、电流密度Dk 2-4A／dm²、镀液温度20-30℃。 在硫酸盐体系工作的基础上，通过查阅大量文献，在氯化物体系中以Hull槽实验对所得镀层进行光亮区的选择以及150ml矩形槽正交实验，确定了Zn-Fe-La三元合金镀层的电沉积工艺。其工艺条件为：FeSO₄·7H₂O 60～120g／L、ZnCl₂ 30～50g／L、LaCl₃ 5～15g／L，KCl 100～1200g／L、C₆H₈O₇·H₂O 10～20g／L、C₆H₇O₇Na₃ 30～60g／L、抗坏血酸2～3g／L、添加剂适量、辅助添加剂适量、pH值2～4、施镀时间10min、电流密度Dk 2～4A／dm²、镀液温度20～30℃ 氯化物体系电沉积Zn-Fe-La三元合金镀层的工艺研究表明，主盐浓度、配位剂C₆H₇O₇Na₃、光亮剂和辅助光亮剂的配合使用以及pH值是影响Zn-Fe-La三元合金镀层成分和性能最主要的因素；但LaCl₂的添加到一定的量后，反而不利于合金的电沉积。此外，导电盐KCl、抗坏血酸、电流密度等对镀层的影响也较大，抗坏血酸在工艺范围内基本上不影响合金镀层的成分，但过多或过少都会影响镀层质量。 分析了稀土的加入对镀层成分以及镀液性能（分散能力、电导率、稳定性等）的影响，结果表明，稀土的加入对镀层以及镀液性能都有很大提高。 在研究了偶氮氯膦-Ⅲ与Re显色条件的基础上，探索了不分离Fe离子，用分光光度法测定镀层中稀土的新方法，Re含量在0～55ug／ml之间时符合比尔定律。结果满意，操作简单，重现性好，可用于日常分析。 通过镀层在pH=7的5％NaCl溶液中的浸泡实验、镀层阴极、阳极极化曲线和在pH=7的5％NaCl溶液中的稳定电位的测定，研究了Zn-Fe-La三元合会镀层的耐蚀性，结果表明，镀层无需钝化具有较高的耐蚀性。Zn-Fe-La三元合会昆明理工人学硕士学位论文摘要镀层的耐蚀性要明显好于Zn一Fe合金镀层，更远远好于Zn镀层。 从双电层结构、吸附抑制机理、欠电位沉积机理和物质结构的角度，针对基液中加入不同种类的稀土盐的阴极极化曲线的不同特征，探讨了Zn一Fe一稀土三元合金电电沉积机理。更多还原

【Abstract】 The author studies the technologies and principles of the sulfate system and electrodeposition Zn-Fe-Re coatings of ternary alloy in this paper ,and how to the electrodepositrion the Zn-Fe-Re coatings of ternary alloy by choosing Lacl3 under the sulfate system. The main processes are as fallows:Through the perpendicularity experiment of 250mlHull’s trough experiment and 150ml rectangle alveus experiment, the electrodeposition technology was confirmed by using the Rare earth salt in the sulfate system as an addition to change the functions of Zn-Fe alloy coatings. The technology conditions should in include:FeSO4.7H2O 80~120g/L, ZnSO4.7H2O 30~50g/L, Ce3(SO4)2 0.6-1. 5g/L, (NH4)2SO4 50~80g/L, C6H8O7.H2O 10~20g/L,H3BO3 5~15g/L, l~3g/L of ascorbic acid, proper addition, PH is 2 to 4,10minutes of electroplate time,Dk= 2~4A/dm2 of electric current density and 20~30癈 temperature of electroplating solution.On the basis of the sulfate system and by consulting a lot of literatures, the author confirms the electrodepositrion technology of Zn-Fe-La coatings of ternary alloy, which is by using Hull trough experiment and rectangle alveus experiment to choose the bright area of the coatings. The technology conditions are: FeSO4-7H2O 30~50g/L, ZnCl2 20~40g/L, LaCl35~l 5g/L, NH4C1 60~90g/L, C6H8O7.H2O 10~20g/L, C6H7O7Na3 20~40g/L,2~3g/L ascorbic acid, proper addition, suitable auxiliary addition, PH2~4, lOminutes of electroplate time, DK=2~4A/dm2 of electric current density and 20~30℃ temperature of electroplating solution.The technological study of chloride system electrodepositrion Zn-Fe-La coatings of ternary alloy shows that coordinated usage of main-salt density, C6H7O7Na3 of complexing agent, shining agent, assistance shining agent, and PH are the main factors that affect the compositions and functions of Zn-Fe-La coatings ternary alloy. However, it is disadvantageous for the alloy’s electrodepositrion when adding LaCl3 to a certain amount. In addition, conductibility salt NH4C1, ascorbic acid and electric current density, and so on also have influence on coatings. Basically, ascorbic acid won’t affect thecompositions of the alloy coatings within the technology, but it will affect more or less the coatings quality.This paper analyzes the influence of the compositions of the coatings and functions of the electroplating solution ( including dispersancy, conductivity and stability, etc. because of adding the Rare earth. The result shows that adding the rare earth can improve the coatings and the functions of the electroplating solution.On the basis of studying the Chlorophosponazo(III) and coloration condition of Re, this paper explores a method of not separating ion Fe but determining the rare earth in coatings through spectrophotographinc. Containing Re content from 0~55ug/mL conforms with Lambert beer’s law. Satisfactory and simple operation, this method can be used in routine anadysis.This paper studies the corrosion resistance of Zn-Fe-La coatings ternary alloy by the experiment of soaking the coatings into 5 % NaCl solution, whose PH is 7, and determining the cathode and anode of the coatings and the stable electric potential of 5 % NaCl solution of PH=7. The result shows that there is high corrosion resistance without passivating the coatings, and that the corrosion resistance of Zn-Fe-La coatings of ternary alloy is better than Zn-Fe-La alloy coating, and is much better than Zn coating.From the point of view of the structure of electrical double layer, adsorption, inhibition mechanism and the under electric potential electric deposition mechanism, and based on the various characters of cathode polarization curve while adding kinds of rare earth salt in basic solution , this paper inquires into the mechanism of electrodepositrion of Zn-Fe-La rare earth of ternary alloy.更多还原