Molybdate and tungstate as corrosion inhibitors for cold rolling steel in hydrochloric acid solution

The inhibition effects of molybdate and tungstate on the corrosion of cold rolling steel (CRS) in hydrochloric acid solution (0.1-0.5 M) were investigated by weight loss and electrochemistry methods. The results reveal that both molybdate and tungstate are very good inhibitors with little concentration. The adsorption of inhibitors on the CRS surface basically obeys the Langmuir adsorption isotherm equation. The effect of temperature on the corrosion behavior of CRS was also studied at 25 °C and 35 °C, the thermodynamic parameters such as adsorption heat (ΔH⁰) and adsorption free energy (ΔG⁰) were calculated. In the same conditions, a comparative study of corrosion inhibition of molybdate and tungstate indicated that molybdate was the better inhibitor in 0.1 M HCl. However, the value of percentage inhibition efficiency (IE) was dependent on the concentration of inhibitors in 0.2-0.5 M HCl. It seemed that molybdate did not have the strong inhibitive effect compared to tungstate with relatively small concentration of inhibitors, but molybdate was a better inhibitor over a wide concentration range of inhibitors. A kinetic study of cold rolling steel in uninhibited and inhibited acid was also discussed. Various parameters such as rate constant k and the kinetic parameter B were calculated for the reactions of corrosion. Polarization curves showed that both molybdate and tungstate are mixed-type inhibitors in acidic media.     

Correction to: An Updated Index Including Toughness for Hot-Cracking Susceptibility

Metallurgical and Materials Transactions A -     

An Updated Index Including Toughness for Hot-Cracking Susceptibility

Metallurgical and Materials Transactions A - Hot cracking is one of the major defects that can occur in laser-based additive manufacturing. During the terminal stage of solidification, hot cracking...     

The effect of neutral red on the corrosion inhibition of cold rolled steel in 1.0 M hydrochloric acid

The corrosion inhibition of neutral red on the corrosion of cold rolled steel in 1.0 M hydrochloric acid (HCl) was studied using weight loss method and potentiodynamic polarization method. Results obtained revealed that neutral red is an effective inhibitor. It was found that the adsorption of neutral red could prevent steel from weight loss and the adsorption accorded with the Langmuir adsorption isotherm. Potentiodynamic polarization studies showed that neutral red mainly acted as a mixed-type inhibitor for steel in 1.0 M hydrochloric acid. Thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy were obtained from experimental data of the temperature studies of the inhibition process at four temperatures ranging from 30 to 45 °C. The most suitable range of inhibitor concentration was discussed. The kinetic data such as apparent activation energies and pre-exponential factors at different concentrations of the inhibitor were calculated, the effect of the apparent activation energies and pre-exponential factors on the corrosion rates of cold rolled steel was discussed. The inhibitive action was satisfactorily explained by using both thermodynamic and kinetic models. Synergism between chloride ion and neutral red was proposed. The results obtained from weight loss and potentiodynamic polarization were in good agreement.     

卫星遥感技术在海洋倾废中的应用进展

海洋污染始终是全球热议问题,人为倾废活动是引起该类问题的主要原因,利用监测手段研究海洋倾废活动可以更好地掌握海洋环境的变化及污染程度。重点总结了传统监测方法及遥感技术在海洋倾废监测中的研究进展,进一步分析了传统方法和极轨卫星在研究中的局限性,探讨了地球同步轨道卫星在实际应用中的进步和优势,结合实际应用结果指出地球同步轨道水色卫星在目前研究过程中存在的问题,并对今后的研究方向进行了展望。     

多媒体技术在高校教学应用中的优缺点分析

本文在对多媒体技术含义和多媒体技术应用的必要性分析的基础上,肯定了其应用中的优点,同时也找出了其很多不足之处,并针对这些不足提出了一些建议性的对策.     

基于Linux的防火墙技术

随着Ｉｎｔｅｒｎｅｔ应用的普及,其安全性总理２也日益突出,详细讨论了如何利用Ｌｉｎｕｘ操作我建防火墙和代理服务器,以实现内部网络的存取访问控制和流量统计的功能。     

部分分散控制及其在单元机组协调控制中的应用

针对强耦合多变量对象控制系统设计中分散控制不能满足高性能要求,而多变量先进控制算法结构复杂、较难推广的现象,研究基于扩展对象的部分分散控制器设计。设计过程首先通过结构分析法得出部分分散控制器结构,再对其对象进行非方扩展,利用非方内模法设计相应非方分散控制器并转化为部分分散控制器,最后应用扩展μ交互法进行稳定性分析。将该方法应用于一500 MW单元机组协调控制系统的仿真研究,结果表明:部分分散控制系统能达到与多变量协调控制系统相近的性能,并且部分分散控制结构更加简单、设计及调试方法更加容易。     

成形磨砂轮圆弧廓形关键参数在位检测方法及试验研究

针对成形磨砂轮精密磨削加工中准确高效地检测砂轮形状精度的需求,提出砂轮廓形参数在位检测新方法.首先采用线状激光位移传感器采集砂轮表面微观形貌数据,构建测量矩阵模型,再通过滤波去噪、宏观轮廓线提取、非线性曲线拟合等算法分析处理出砂轮廓形曲率半径和圆度误差检测指标.通过磨削验证试验分析和检测不确定度评定,证明该方法稳定可靠...