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恒电量瞬态响应的频谱分析Ⅰ.原理与测试方法 总被引:2,自引:0,他引:2
在用时频变换测量电极阻抗的技术中,介绍了用恒电量作为激励信号的时域法阻抗测量技术,分别用等效电路和实际腐蚀体系验证了恒电量测量的精确性,同时体现快速测量的特点.提出用拉普拉斯频谱分析恒电量瞬态响应的方法。不仅能够简化恒电量激励条件下电路模型的解析,而且对于包含多个时间常数的腐蚀体系,有助于判断腐蚀反应的子过程和解析电极阻抗. 相似文献
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采用线性扫描伏安法和恒电位法研究了扫描速率、电解质浓度以及卤素离子的种类和浓度等对碳钢/H2SO4体系电流振荡现象的影响.结果表明,这些因素均对该体系的电流振荡产生明显影响.不同卤素离子对碳钢/H2SO4体系电流振荡动力学行为影响的强弱顺序为:Cl^-〉Br〉I^-.恒电位极化测试显示,卤素离子存在时碳钢阳极电溶解中可... 相似文献
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基于恒电量的酸性缓蚀剂快速评价方法研究 总被引:3,自引:1,他引:3
利用恒电量法快速测量了Q235钢在0.5mol/L硫酸溶液及其硫脲缓蚀溶液中的腐蚀,建立了新的解析方法获得Tafel常数,探讨了恒电量激励条件下的等效电路,同时用电化学阻抗谱进行验证。结果表明:恒电量法不仅能快速测量Rp和Cd值,而且可以及时获得添加缓蚀剂前后的B值,对于表面状态变化快的酸性缓蚀体系,能更加直接、准确地评价缓蚀剂;对恒电量测量,可以避免缓蚀剂吸脱附等慢过程的影响,用简单模型获得的Rt值的大小,将大大地简化了酸性缓蚀剂的评价。 相似文献
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本工作采用恒电量技术,分析恒电量微扰下的△E~t衰减曲线以获得塔菲尔斜率。这种断电的松弛方法不受溶液电阻的影响,因而特别适用于高阻介质和涂装金属体系。该方法以电化学基本方程为基础,结合恒电量微扰技术原理。使用基尔霍夫和结点电流公式列出微分方程组,然后采用四阶龙格——库塔法解微分方程组。可将△E值缩小到±10mV的范围。对几个实验体系所进行的试验验证了本方法的可行性。 相似文献
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分别采用恒电流充电法和小幅三角波法监测Q235钢在海水中的腐蚀情况。结果表明,恒电流充电法和小幅三角波法能够较好地监测其在海水中的腐蚀情况;恒电流充电法推荐采用阴极极化,外加恒电流-3或-5μA/cm2,极化时间1 min;小幅三角波法推荐采用阴极极化,扫描速率0.1或0.2 mV/s。 相似文献
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采用线性电位扫描化曲线测试,以及恒电位极化下磁场扰动法研究了磁场对铜在氯钠溶液中的阳极溶解的作用,在阳极表观Tafel区,无磁场时恒电位极然后外加磁场使阳极电流密度增大,有磁场时恒电位极化然后撤去磁场使阳极电流密度减小,磁场通过加速电极溶液界面的传质过程而加速阳极溶解,由于Cu/NaCl与Fe/H2SO4体系阳极Tefel区速率控制步骤不同,会导致不同的磁场效应作用。 相似文献
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C.M. Sulyma P.C. Goonetilleke D. Roy 《Journal of Materials Processing Technology》2009,209(3):1189-1198
The voltage pulse modulation technique is useful for electrochemical processing of metal and alloy surfaces by utilizing faradaic reactions like electro-deposition and electro-dissolution. A theoretical framework is presented here to facilitate quantitative analysis of experimental data (current transients) obtained in this approach. A typical application of this analysis is demonstrated for an experimental system involving electrochemical removal of copper surface layers, a relatively new process for abrasive-free electrochemical mechanical planarization of copper lines used in the fabrication of integrated circuits. Voltage pulse-modulated electro-dissolution of Cu in the absence of mechanical polishing is activated in an acidic solution of oxalic acid and hydrogen peroxide. The current generated by each applied voltage step shows a sharp spike, followed by a double-exponential decay, and eventually attains the rectangular shape of the potential pulses. The formulas presented here show excellent fits to these current transients, and help to probe the detailed electrochemistry of surface layer removal using a simple circuit model of the reactive interface. 相似文献
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《金属精饰学会汇刊》2013,91(2):102-108
AbstractThe development of any pulse sequence is a highly knowledge based process. Beside the knowledge of electrochemical electrolyte properties, the tailoring of the actual field line distribution and the local surface potentials via the applied pulse sequence is the main focus of the scientific development. The combination of pulse plating and numerical simulation offers a very high success rate for definition of pulse plating processes. Simulation tools are the only option to study current distribution and potential fields and are applicable for any possible electrolyte system and cell geometry. For developing a pulse plating sequence it is of major importance that the effect of single pulses within a pulse sequence can be calculated stepwise in high precision, taking into account the change of the substrate surface and geometry after each pulse step. Only in this way can the exact influence of cathodic and anodic pulse steps be retrieved. Additionally, the consideration of shieldings and cell geometry can be performed in parallel. Within this work a detailed study of the correlation between experimental data and the results of numerical simulation was performed focusing on the system Watts Nickel on steel. The conformity revealed by this study is excellent. The numerical simulation tool can be used for development and optimisation of pulse plating processes, if a stepwise, shape alteration including mathematical algorithm is used. 相似文献
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The present paper describes an electrochemical method of determining the porosity of thin brass coatings by measuring the rate of change in polarization conductance of the system: brass coating—steel substrate—electrolyte. A theoretical explanation of the electrochemical principle of the method is offered. The influence of different factors of the electroplating process, such as pulse current frequency and the presence of a specific additive in the electrolyte, on the porosity of brass coatings has been investigated.Plating conditions under which coatings have minimum porosity are established. There is a close correlation between porosity parameters obtained by this method and rubber adhesion of brass coatings deposited on steel wires. 相似文献
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采用电化学噪声EN(electrochemical noise)技术和基于Compact RIO的分布式大气腐蚀便携式现场实时监测系统,对北京地区大气环境下2B06铝合金腐蚀过程进行长期监测,并对采集的电化学噪声信号进行统计分析,探索了电化学噪声方法在铝合金腐蚀现场监测方面的应用及腐蚀速率表征参数,从而对腐蚀进行预测并减小损失。结果表明:该系统可对铝合金的大气腐蚀过程进行现场实时监测,电化学噪声电阻Rn和电流噪声标准偏差SI可作为反映铝合金大气腐蚀速率的表征参数;长期监测结果显示北京地区的2B06铝合金在相对干燥的秋冬季节腐蚀较缓。 相似文献
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直流电机调速实验教学综合平台以C8051F040为主控芯片,进行双闭环可逆直流PWM调速系统全数字化设计。提出一种利用C8051单片机的可编程计数器阵列输出16位PWM波的方法取代数字脉冲触发器。主要设计了电流采样、转速检测、模数转换、脉宽调制信号生成、电机驱动等电路。采用调节器工程设计方法,设计电流和转速调节器的PI参数,通过MATLAB验证和软件编程实现。该系统具有转速、电流和PI参数键盘输入和在线修改功能,电机旋转方向判断,转速、电流及功率模块的温度显示和报警功能。该实验教学平台实际运行可靠,能满足实验教学的要求。 相似文献
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液压系统因其独特的特性,在各个领域有着广泛的应用。液压设备的运行安全与状态监测是生产中的一项重要内容。由于液压系统的所有部件都在封闭油路中工作,故障源的定位比较困难。为了解决这个问题,本文提出了一种基于物联网技术的动态故障诊断方法GRNN模型的基于物联网的智能控制,利用无线传感器网络技术在分布式液压设备中各参数的实时测量和控制,远程数据共享、故障信号的采集输入GRNN模型故障观察器,检测阈值,通过实验模拟准确诊断系统故障。实验表明,该方法可以有效地应用于过程生产液压系统中,保证系统的正常运行,降低设备故障率,提高生产效率。 相似文献
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《金属精饰学会汇刊》2013,91(3):145-148
AbstractZinc–nickel alloy was electrodeposited on stainless steel using pulse current deposition (PED) from a chloride–sulphate bath. Duty cycles were varied between 10 and 80% and frequency was changed from 10 to 100 Hz. The deposit characteristics were analysed using SEM, XRD and AFM and the results are presented in this paper. The corrosion resistance of zinc–nickel alloy deposited from direct current deposition (DCD) has been compared with that of the deposit obtained by pulse current using the electrochemical impedance spectroscopy method. 相似文献