HEDP镀铜液在铜电极上的电化学行为

采用测量开路电位-时间曲线和阴极极化曲线的方法,研究了铜电极上HEDP镀铜的电化学行为.结果表明,HEDP体系的溶液组成与温度都会影响铜电极的稳定开路电位,电镀铜过程的阴极极化(镀层结晶质量)与极化度(镀液分散能力).溶液中HEDP浓度升高,则稳定开路电位变负,阴极极化和极化度增大,有利于电沉积铜的电极过程.溶液pH升高时,稳定开路电位变负,电沉积铜的阴极极化增大.溶液温度降低时,电沉积铜的阴极极化增大.阴极极化较小时的极化度较大,且随pH的升高或温度的降低而明显增大.     

铁电极上HEDP镀铜的电化学行为

通过测量开路电位一时间曲线和阴极极化曲线,研究了HEDP镀铜液在金属铁上电沉积铜的电化学行为.结果表明,HEDP镀铜液的组成影响金属铁在溶液中的稳定开路电位和金属铁上电沉积铜的阴极极化.增大溶液中HEDP的浓度或提高HEDP与Cu2+的摩尔比,铁电极的稳定开路电位负移,可减缓和消除铁与铜离子的置换反应,提高铜镀层与铁基体的结合力;金属铁上电沉积铜的阴极极化增大,有利于得到致密的铜镀层.镀液pH升高,铁在镀液中的稳定开路电位稍有正移,但在金属铁上电沉积铜的阴极极化增大,在HEDP镀铜液中电沉积铜的阴极过程发生电化学极化,阴极极化曲线服从Tafel关系.     

pH对低温镀铁组织形貌及性能的影响

介绍了低温镀铁的工艺配方及流程.利用扫描电镜观察了镀层的组织形貌,利用硬度计测试了镀层硬度,利用锉刀法和热震法检验了镀层的结合强度,考察了pH对沉积速率、显微硬度和耐蚀性能的影响.结果表明,所得镀层结合力良好,pH为1.0时,沉积速率最高,耐蚀性能最好;镀层硬度随pH的升高而增大,最大值为587.43 HV.     

钢铁基体酒石酸盐碱性无氰镀铜

以酒石酸盐为络合剂,胺化合物为辅助络合剂,研究钢铁基体上碱性无氰镀铜工艺,探讨了搅拌、镀液温度、pH、ρ(Cu2+)和添加剂对镀层外观的影响.考察了镀液的深镀能力和抗Fe2+、Fe3+、Zn2+及Sn4+杂质能力以及镀层与铁基体的结合力.实验结果表明:可以在宽广的工艺条件下获得光亮的铜镀层;阴极电流效率随温度、pH和ρ(Cu2+)提高而增大,在实验确定的工艺条件下ηκ为82%左右;镀液深镀能力达91%;计时电位曲线试验结果表明,基体上的钝化膜在沉积初期被破坏而处于活化状态,使得铜镀层与钢铁基体有足够的结合力.     

化学镀锡层结构及性能研究

用化学法在铜基体上沉积出锡镀层。通过扫描电镜和X-衍射分析了化学镀锡层的成分和结构。测定了锡镀层的孔隙率、可焊性和结合力。结果表明：镀层为铜锡合金,同时含有微量的碳、氮、铁、硅等元素,锡含量随施镀时间的延长而提高,说明共沉积为连续自催化沉积,锡镀层相对于铜而言是阳极性镀层,对铜具有很好的电化学保护作用。     

工艺参数对电镀镍铜合金镀层成分及相结构的影响

采用由200 g/L NiSO4·6H2O、10 g/L CuSO4·5H2O、80 g/L Na3C6H5O7·2H2O、0.2 g/L C12H25SO4Na和0.5 g/L糖精钠组成的镀液,在10~60 mA/cm2、pH=2.5~5.0和25~50°C条件下电沉积制备了NiCu合金镀层。探讨了镀液pH、电流密度、温度等工艺参数对镍铜合金镀层相结构和组成的影响。结果表明,NiCu合金镀层的铜含量随电流密度或温度升高而增大。但随pH增大,镀层铜含量降低,pH小于4.0时,NiCu合金镀层中含有单质铜。     

镀锡铁基体的化学镀铜

为了提高铁的耐蚀性,在镀锡铁基体上进行了化学镀铜的研究。系统地研究了柠檬酸-酒石酸二元配位体化学镀铜体系中各因素对镀速的影响。结果表明,柠檬酸-酒石酸二元配位体系的镀速大于柠檬酸单配位体系的镀速。随着CuSO4.5H2O、柠檬酸、酒石酸、次磷酸钠浓度的增大,以及随着pH和温度的升高,镀速均先升高后降低。化学镀铜液的最佳组成为：CuSO4.5H2O 12 g/L,柠檬酸40 g/L,酒石酸40 g/L,次磷酸钠20 g/L,抗氧化剂1 g/L,硼酸10 g/L,表面活性剂0.1 g/L。最佳温度为55～60℃、pH为1.25～1.76。在最佳条件下,铜的镀速为5.06μm/h,获得的镀层表面光亮平滑,结晶致密,耐蚀性良好。铜锡镀层之间、锡镀层与铁基体之间的结合力优良。     

电镀级焦磷酸钾品质快速评价的电化学方法研究

应用线性扫描伏安法和计时电位法分别测量绘制阴极极化曲线和恒电流电位-时间曲线,研究了铜电极上焦磷酸盐镀铜的电化学行为。结果表明,焦磷酸盐镀液的组成、pH和温度都会影响铜电极电镀过程的阴极极化和恒电流电位。在镀液中,在焦磷酸根与Cu2+质量比为8∶1,Cu2+浓度为0.28～0.39mol/L,镀液pH值为8.8～9.3,镀液温度为45～48℃条件下,有利于得到结晶质量较好的铜镀层。阴极极化越大,恒电流电位越负,对应镀液越容易得到致密的金属镀层,与赫尔槽实验效果一致。阴极极化曲线和恒电流电位-时间曲线可用于电镀级焦磷酸钾品质的快速评价。     

钨粉表面化学镀铜沉积过程中的开路电位

采用电化学工作站测试了化学镀铜液中钨片及钨粉压片表面开路电位的变化规律,并对化学镀铜钨片及铜包钨复合粉进行了分析. 结果表明,刚浸入化学镀铜液时,钨粉开路电位约为-600 mV,经微增、速降过程后短时达到稳定电位(约-870 mV),之后再迅速升高,300 s时基本达到稳态沉积电位(约-690 mV),此时,铜单膜层包覆基本完成. EDTA×2Na与TART复合络合剂通过调节钨粉表面电荷分布促进铜包覆反应,微量(≤10 mg/L)添加剂2,2￠-联吡啶能有效抑制镀层中Cu2O生成,改善镀层质量.     

PE塑料化学镀铜的研究

采用锉刀实验法和划线划格实验两种镀层结合力测试方法,对化学镀铜层与塑料基体之间结合力的优劣进行了定性评价;通过沉积速率的计算,研究了镀铜时间对塑料化学镀铜沉积速率的影响。结果表明,镀层与基体之间的结合力良好塑料表面可通过化学镀形成铜镀层,且随着镀铜时间的增加,沉积速率增加(30 min内)。镀铜10~15 min时,沉积速率相对较低,而镀铜15 min后,沉积速率急剧增大。     

发泡铜阴极电沉积法回收酸性镀铜废液中的铜

用发泡铜作阴极材料, 从稀的酸性镀铜废液中电沉积回收金属铜,测定了阴极极化曲线,考察了pH值、电解液循环速率、电流密度等工艺参数对阴极电流效率的影响. 结果表明:用发泡铜作阴极材料,可有效地处理含铜废液和回收金属铜,将含Cu2+ 200 mg/L的废液在1.2 A/dm2表观电流密度下处理至含Cu2+ 0.5 mg/L以下,平均电流效率可达85%以上.     

As3+浓度对阴极铜稳态极化曲线平衡电位的影响

用稳态法研究了砷离子、硫脲及骨胶等对铜电解液中阴极铜极化曲线平衡电位的影响.结果表明,当Cu2＋为1g/l时,溶液中加入As3＋,系统的平衡电位明显比未加入As3＋时增加;当Cu2＋为8g/l、15g/l时,溶液中加入As3＋后,系统中铜的平衡电极电势比纯铜系统降低.     

Spontaneous passivation observations during scale formation on mild steel in CO2 brines

Previous study revealed localized corrosion in CO₂ environments was driven by a galvanic cell established between pit surfaces and scaled surrounding area. In order to underpin the understanding of the galvanic mechanism of localized corrosion, the root cause of potential differences between these two surfaces, passivation of mild steel, in CO₂ environments was investigated using transmission electron microscopy technique and electrochemical techniques including potentiodynamic polarization, cyclic polarization and open circuit potential techniques. Potentiodynamic polarization experiments showed that the passivation of the carbon steel surface favorably occurred at pH > 7 and facilitated with the presence of FeCO₃ scale. Cyclic polarization tests showed that polarization rate had an important influence on passivation behavior. At a slower polarization rate, lower passivation potential and current density were observed. Spontaneous passivation was evidenced by a significant increase of corrosion resistance and an open circuit potential without any externally applied current or potential during electrode immersion. This process is affected by pH, temperature, presence of CO₂ and iron carbonate. Nevertheless, iron carbonate film is not the only one responsible for passivation, as demonstrated from depassivation tests where passivity was lost without losing the existing iron carbonate film. Transmission electron microscopy technique was used to determine the structure of the passive layer. An extra phase, most likely magnetite, was observed to be beneath the iron carbonate scale and at the crystal grain boundaries which passivated the mild steel.     

Effect of methanol crossover on the cathode behavior of a DMFC: A half-cell investigation

A half-cell consisting of a normal direct methanol fuel cell (DMFC) cathode and a membrane that contacts with an electrolyte solution was developed to investigate the effect of methanol crossover on the cathode behavior. Open circuit potentials, cyclic voltammetry profiles, polarization curves and electrochemical impedance spectroscopy (EIS), resulting from the oxygen reduction reaction (ORR) with/without the effect of methanol oxidation reaction (MOR), were measured. The transient measurements indicated that both current and open circuit potential of the electrode exhibited significant oscillations when the anodic MOR was superposed on the cathodic ORR, which explain the instabilities that may be encountered in the practical DMFC operation. The steady-state results confirmed that the presence of methanol at the cathode led to a significant poisoning effect on the ORR, especially when the DMFC operates at higher methanol concentrations and discharges at lower potentials. More importantly, the half-cell was proved to be ideal for the EIS study of DMFC electrodes because the system not only facilitates an accurate potential control but also reflects the actual mass transport process that occurs in practical DMFCs.     

铜合金管循环冷却水预膜方案及其电化学研究

通过正交试验,考察了利用苯并三氮唑（BTA）对铜合金进行预膜的预膜方案,并在此基础上讨论了预膜剂的浓度、pH以及时间对预膜效果的影响。结果表明,pH值是影响预膜效果的重要因素,最佳的pH值界于7～8之间,BTA的浓度在50mg／L时效果最好。通过失重法、线性扫描伏安法（LSV）、Tafel极化曲线以及电化学阻抗谱（EIS）对预膜前后铜片的电化学研究表明：预膜后试片的耐蚀性明显提高。     

pH值对高锰酸钾作阴极的微生物燃料电池阴极电位的影响

构建了一个以葡萄糖水溶液为阳极原料,高锰酸钾为阴极氧化剂的双室微生物燃料电池。考察了MnO_4溶液的pH值对MFC产电性能的影响。结果表明,在pH值不同时,其对MFC的还原电位和MnO_4的还原产物有显著影响。当pH>3时,阴极E°=+1.51V,当pH>11时,E°=+0.56V。研究表明:(1)二氧化锰沉淀是导致阴极极化的主要原因,当阴极电解液流动时可有效抑制二氧化锰的沉淀。(2)根据电池电压曲线图判断,pH值对电池的阴极电位有较大影响,电池电压的变化与阴极电位变化具有很好的一致性,但不会对阳极电位造成影响。(3)pH值对阴极电势的影响符合Nernst方程。     

微电解处理酞菁绿废水中铜的研究

利用铁屑微电解法处理酞菁绿生产过程中高浓度的含铜废水,通过试验,考察了废水pH值、铁屑用量、铁屑粒径及反应时间等因素对铜去除率的影响。试验结果表明:在废水pH值为1.5、铁屑用量为1%、铁屑粒径为60目、反应时间为40min的条件下,铜的去除率可达99.9%左右,可使出水铜的质量浓度在1mg/L以下。     

Copper Deposition and Formation of Nano-Particles

The cementation of copper ions from copper sulfate solution was studied using iron wire and iron powder. The influence of initial copper concentration has considerable effect on cumulative copper deposition. The copper deposition rate data could be interpreted by using shrinking core model. The effects of temperature and pH were substantial and have been studied and interpreted. The activation energy of the system within the temperature range of 23–54°C was found to be 14.23 (iron wire) and 30.20 kJ per mol (iron powder), respectively. The morphology of copper deposits studied showed that the reactions have the potential to produce particle sizes within nano range.