A Study of the Relation between Current Oscillations and Pitting

Anodic polarization behaviors of iron in pure H2SO4 and three mixed acidic solutions, H2SO4 NaCl，H2SO4 NaNO3 and H2SO4 NaCl NaNO3, were investigated. The potentiodynamie sweep curves showed that the current densities rose and dropped irregularly in H2SO4 NaCl solution at the more anodic potentials since the iron surface suffered pitting attack in the solution, but the pitting corrosion was inhibited effectively in the presence of nitrate ions. The surface morphological measurements indicated that pits appeared on the iron surface in H2SO4 NaCl solution and only a few unobvious corrosion spots were observed in H2SO4 NaCl NaNO3 sointian after the iron electrode was potentiostatically polarized at 1.3 V. The oscillatory properties of iron are associated with the susceptlbility of the iron to pitting. In H2SO4 NaCl solution, the regular potentiostatic current oscillations gradually evolved into the irreg-niar current fluctuations due to occurrence of the pitting; whereas in H2SO4 NaCl NaNO3 solution, the current oscillations took place regularly, like the oscillatory behavior in the pure H2SO4 solution. Thus, when the higher the oscillatory fre-quency, the more irregular oscillatory process and the more sensitive to pitting iron occurred.     

电化学技术制备纳米材料研究的新进展*

利用电化学方法制备与组装纳米材料是近年来发展起来的一项新技术.本文对电化学方法在纳米材料制备中的应用及其研究进展做了较为全面的概述,着重介绍了模板电化学法合成纳米材料、稳定剂保护下电化学还原法制备金属溶胶、电化学台阶边缘修饰法制备一维纳米材料以及脉冲超声电化学法制备纳米粒子,并对其应用前景做了展望.     

基于离心技术的金纳米粒子表面清洁方法和机理研究

本文发展了一种基于离心技术的清洗金纳米八面体表面十六烷基三甲基溴化铵(CTAB)吸附物的有效方法.选择合适的离心转速和离心次数,可以驱除金纳米八面体表面的CTAB分子.通过热失重分析、表面增强拉曼光谱和傅里叶红外光谱表征可以推测,金纳米八面体经合适的离心清洗后,表面残留的少量CTAB分子通过疏水作用由烷基长链与金表面形成(亚)单层吸附,同时,与金表面有强相互作用的溴离子发生脱附.溶剂水对CTAB的稀释在离心清洗金纳米八面体表面的过程中发挥着重要作用.金纳米粒子在离心场中的高速运动导致粒子周围双电层发生极化,极化双电层内产生的局部液流引起双电层内物质交换从而也影响了金纳米八面体表面的清洗效果.金纳米八面体在硫酸溶液和碱性硝酸铅溶液中的电化学研究表明,经过离心清洗的金纳米八面体可以直接应用于单晶电化学研究.