节能型Al基/TiB2/Mn、Pb、La系氧化物涂层电极制备与性能的应用基础研究

It is recognized that the electrode has been the key material in hydrometallurgy, but the choice and preparation of electrode material is a difficult problem in hydrometallurgy industry. In this project, from the point of view of the selection and structural desigin of electrode material, the new design proposal of electrode structure is presented that the aluminum coated with TiB2 is selected as the substrate material and the oxide Mn, Pb and La is selected as active coating. It is discussed that the substrate material is on the influences of the manufacturing process, the bonding condition of the interface and the microstructure evolution on the electrode reaction. The relationship between the coating composition and electrode performance is studied, meanwhile, based on the theory of thermodynamics and electrochemical kinetics, it is carried on sutudy that the micro-factors such as the coating composition, their solid solubility, grain size, surface roughness et al. is impact on the properties of surface fractal dimension, electrochemical kinetics and cyclic voltammetry. It is revealed that the effect of the formation mechanism of interface and the microstructure of coating is mechanism of action on the improvement of catalytic activity and the increase of service life. Based on the theory of the electrode process kinetics and thermodynamics, it is studied that the effecting law of the electron transmission way, electron transformation mechanism and the electric work function on the electrode potential and chemistry reaction speed during the electrolyzing reaction course is analyzed through a lot of tests.The key factor which the change of matrix material property is on the effect of the negative shift value of electro potential and saving enery saving is been recognized in hydrometallurgy.

电极是湿法电解（电积）中的关键材料，电极材料的选择和制备是湿法冶金工业的难题之一。本项目将从电极材料的选择和结构设计入手，提出以导电好、耐蚀强的TiB2包铝为基体，以Mn、Pb、La氧化物为活性涂层的新型电极结构设计方案。探讨合成过程、界面结合状态以及演变行为对电极反应的影响规律。考察涂层成分配比与电极性能的关系，并结合晶体结构学、电化学动力学，研究涂层的组织结构、固溶关系、晶粒大小、表面粗糙度等微观因素对电极的动力学参数、循环伏安特性、表面分形维数等的影响关系，揭示材料界面形成机制、涂层微观结构对提升电极催化活性、延长使用寿命的作用机理。利用电极过程动力学、电化学热力学，研究Al/TiB2基体材料的电子传输方式、转移机制和电子逸出功的改变对阳极过程电极电势、反应速度的影响规律，弄清基体材料性质的改变与电极极化电位负移，实现节能降耗的关键因素和作用规律。

本研究利用金属陶瓷TiB2所具有的优异特性，采用等离子喷涂法制备出了新型具有金属陶瓷TiB2中间层的Al基复合电极基体材料，并通过电镀法，在新型基体材料表面制备出具有高活性、耐腐蚀的β型PbO2活性涂层。 . 结果表明：通过改变电极基体材料结构组成，实现了电极材料耐腐蚀性能的提高、表面电流分布更加均匀以及电催化活性的改善。结合电化学工作站的测试，对新型电极材料的Tafel腐蚀曲线、循环伏安曲线以及交流阻抗谱的测试分析，表明在电化学反应过程中，由于金属陶瓷TiB2以及表面活性涂层β型PbO2的高稳定性能，降低了电极材料在腐蚀过程中的腐蚀电流密度、表面交换电流密度下降6个数量级，使得电极材料的耐蚀性能提高，从而延长了电极材料的强化寿命(较Ti基的强化寿命提高80%)。在析氧极化过程中的交换电流密度提高近10倍之多、表面的传递系数增大了6.47%，电极表面的活性涂层的伏安电荷数(Q外)增大16.14%，催化活性点数提高，加快了电极的电化学反应速率，从而使得新型复合电极材料的电催化活性增大。同时，由于Al基体具有的优异导电性能，电极表面的电势分布更加均匀(同距离的电势变化范围降低了85.23%)，为电极材料性能的改善奠定基础。. 通过在电沉积金属Ni的电化学反应体系中进行模拟生产试验，通过各项参数的测试比较，与传统Pb合金电极比较，表明了新型Al基复合电极材料能够实现降低槽电压(可降低10.34%)、提高电流效率(提高8.76%)、减少电能消耗(降低24%)以及改善产品质量(杂质Pb含量降低73.19%)等过程，特别是在降低能耗方面表面尤为突出，可以利用比传统Pb合金电极低340 kWh的电能，生产出接近于2倍的产量。. 综上所述，本研究实现了新型具有金属陶瓷TiB2中间层的Al基复合电极材料制备，其具有优异的电化学性能，同时在工业实际应用中也表现出了巨大的应用潜力，为能够实现“低能耗、高产出”的生产模式奠定基础本研究为电化学工业的发展提供增添了一种新的电极组成结构，为节能型低成本的新型电极材料开辟出一条新的途径。