Effect of alternating voltage passivation on the corrosion resistance of duplex stainless steel

Potentiodynamic polarization and E _corr versus t curves were obtained, together with electrochemical impedance spectroscopy (EIS) measurements, in order to understand the effects of alternating voltage (AV) passivation on the corrosion resistance of duplex stainless steel (DSS). SEM, EDS and XPS were employed to further investigate the influence of AV passivation on the properties of the passive film. The results of the electrochemical measurements showed that AV passivation significantly improved the corrosion resistance of DSS. SEM images indicated that the surface exhibited a unique morphology after AV passivation treatment, and XPS results suggested that AV passivation greatly increased the thickness of the passive film. Furthermore, significant chromium enrichment and a higher ratio of Fe³⁺/Fe²⁺ were observed in the passive film after AV passivation. Mott–Schottky results confirmed that AV passivation had a strong influence on the semiconducting properties of the passive film.     

盐酸酸洗咪唑啉型缓蚀剂IM的研究

以玉米油为原料合成了一种新型的咪唑啉型缓蚀剂IM ,利用静态失重法测定了该缓蚀剂在盐酸介质中对 2 0A碳钢的腐蚀速度和缓蚀效率 ,探讨了其缓蚀机理。结果表明 ,该缓蚀剂在盐酸介质中对 2 0A碳钢具有较强的缓蚀能力     

盐酸介质金属缓蚀剂最新进展

对盐酸介质中金属材质腐蚀的机理以及研究现状进行了分析和概述。目前,人们认识到金属材质在盐酸溶液中腐蚀速度与酸度和氯离子浓度有关。而针对就盐酸溶液中的氯离子以及氢离子在金属的腐蚀过程发挥多大的功效,以及金属材质的阳杉阴极反应是如何进行的动力学问题的研究成为该领域的主要趋势,以解决金属材料在盐酸介质中腐蚀问题。     

The anodic dissolution of copper in hydrochloric acid solutions

The electrodissolution of copper in hydrochloric acid solutions at the rotating ring-disk electrode was found to be controlled by both mass transfer and reaction in the apparent-Tafel region in HCl concentrations of between 0.1 and 1.0 M. The proposed mechanism describes the adsorption of CuCl_ads on the corroding copper surface and the diffusion of CuCl⁻₂ from the copper surface. The reaction in the limiting-current region was found to be controlled by the diffusion of Cl⁻ to the copper surface through a porous CuCl layer that forms on the surface. The thickness of this porous layer is dependent on the stirring conditions, and independent of the Cl⁻ concentration. Cu²⁺ is also produced at the Cu surface during electrodissolution. A mechanism describing the formation of a porous film of CuCl on the surface, the diffusion of Cl⁻ through this film and the formation of Cu²⁺ has been proposed.     

盐酸介质中新型缓蚀剂研发进展

对盐酸介质中金属材质腐蚀的机理以及研究现状进行了分析和概述。对缓蚀剂的研发做出了展望。     

盐酸溶液中二乙烯三胺对黄铜的缓蚀作用及吸附热力学研究

采用失重法研究了不同温度下不同浓度的二乙烯三胺在10%的盐酸介质中对黄铜的缓蚀作用.结果表明,二乙烯三胺在10%的盐酸介质中对黄铜的脱锌腐蚀有良好的抑制作用,二乙烯三胺在黄铜表面的吸附规律基本服从Langmuir等温式,由此获得相关热力学参数.     

Effects of NO2 on the corrosion of Ni in phosphate solutions

The influence of NO₂⁻ on the corrosion of Ni in acid phosphate solutions were analysed by means of potentiodynamic scans and impedance spectroscopy under electrode rotation. The complex nitrite reduction reaction involves adsorbed intermediates which interfere with the surface process occurring during the active dissolution and passivation of Ni. Near the corrosion potential, the reduction of NO₂⁻ follows a Tafel’s behaviour independent from nitrite concentration and electrode rotation speed, denoting a surface-controlling step. Without NO₂⁻, the adsorption of H predominates in the cathodic polarisations. The adsorption of NO₂⁻ near the corrosion potential has several consequences: (i) it brings about a lower surface coverage of NiOH decreasing the rate of Ni active dissolution and (ii) its preferential adsorption against that of passivating species, such as NiOH and Ni(OH)₂, hinders the formation of the pre-passive layer at low pH-values increasing the passivation current.     

盐酸生产工艺技改总结

介绍了针对盐酸吸收工艺进行的改造.吸收尾气后的废水进行闭路循环并用作盐酸的吸收剂,杜绝废水的直接排放,并节约大量用水;改HCl气体空冷管为浸水石墨管,提高了盐酸的产量,不产生黄色的冷凝酸.     

盐酸水解玉米秸秆木聚糖的动力学研究

对稀盐酸水解秸秆半纤维素生成木糖水解液过程进行动力学研究。分别测定了不同温度下,不同水解时间水解液中木糖质量浓度以及其降解产物糠醛的质量浓度。利用Saeman模型拟合木糖生成过程。实验表明,该模型能够较好地描述木糖生成过程以及其降解产物糠醛的产生过程。通过曲线拟和确定了不同水解温度下木糖的生成速率以及分解速率常数,同时利用Arrhenius方程确定木糖生成活化能Ea为116 kJ/mol。综合比较不同温度下水解液中的木糖以及糠醛质量浓度,确定使用质量分数为2%的稀盐酸于120℃下水解60 min为最佳水解条件。其水解液中木糖质量浓度可达20.99 g/L,糠醛质量浓度可维持在1.46 g/L以下。     

盐酸生产与分析中应注意的几个问题

对盐酸质量分析中出现的酸度低、酸度分析指示剂不显色等问题进行了讨论。     

盐酸溶液中糠醛对锌的缓蚀作用

采用失重法研究了不同温度下,不同浓度的糠醛在3％盐酸体系中对锌的吸附及缓蚀作用,并应用吸附理论处理实验数据。结果表明糠醛对锌在盐酸介质中的腐蚀有良好的抑制作用,该物质在锌表面产生了吸附,且低浓度下的吸附基本符合Langmuir等温式,吸附过程为放热反应,随着温度的升高,吸附能力减弱,缓蚀效率下降。     

The anodic dissolution of 90% copper-10% nickel alloy in hydrochloric acid solutions

The anodic dissolution of the 90% copper-10% nickel alloy in hydrochloric acid solutions at the rotating disk was found to be controlled by both mass transfer and reaction in the apparent Tafel region. The kinetics of dissolution are similar to those of pure copper for the partial currents due to the dissolution of both the copper and nickel components from the alloy. A mechanism for the dissolution of the alloy is proposed. This mechanism describes the dissolution as being controlled by the dissolution of the copper from the alloy. In the limiting-current region a film of CuCl precipitates on the surface of the electrode. The reaction in the limiting-current region is controlled by mass transfer. A mechanism which describes the precipitation and dissolution of this film, and which describes the diffusion of the chloride to the surface of the electrode is proposed.     

二合一副产蒸汽氯化氢合成炉运行总结

介绍了二合一副产蒸汽氯化氢合成炉的工艺流程、运行特点及效益分析,实践证明,二合一副产蒸汽炉具有先进性、经济性及实用性。     

磷钼酸在硫酸-醋酸体系中对304不锈钢的缓蚀性能研究

考察了磷钼酸在硫酸一醋酸混酸介质中对304不锈钢的缓蚀性能,对缓蚀机理进行了初步推断。实验结果表明,磷钼酸是一种阳极型缓蚀剂,在ω(H2SO4)=0．5％～1．5％、ω(CH3COOH)=58．0％、ω(HPA)=0．1％～0．2％,温度100～120℃的条件下,腐蚀速度小于0．05mm／a,缓蚀率高迭99．7％。     

盐酸中原儿茶醛在钢表面的吸附及缓蚀作用

用失重法和动电位极化曲线法研究了在1.0mol/L HCl中20~50℃原儿茶醛(3,4-二羟基苯甲醛)在冷轧钢表面上的吸附及缓蚀作用.结果表明:原儿茶醛具有中等程度的缓蚀作用,为混合抑制型缓蚀剂,缓蚀率随原儿茶醛的浓度增加而增大,但随温度的增加而减小;原儿茶醛在钢表面的吸附符合Freundlich吸附模型.通过吸附理论和动力学Arrhenius公式求出了相应的吸附热力学参数(吸附自由能ΔG°,吸附热ΔH°,吸附熵ΔS°)和动力学参数表观活化能Ea,并根据这些参数详细讨论了缓蚀作用机理.     

盐酸溶液中香兰素在钢表面的吸附及缓蚀作用

用失重法和动电位极化曲线法研究了香兰素(4-羟基-3-甲氧基-苯甲醛)在1.0 mol/L HCl中20～50℃下在冷轧钢表面上的吸附及缓蚀作用.结果表明:香兰素在HCl中为阴极抑制型缓蚀剂,缓蚀率随香兰素的浓度增加而增大,而随温度的增加而减小;香兰素在钢表面的吸附符合Temkin吸附模型.通过吸附理论求出了相应的吸附热力学参数(吸附自由能ΔGo,吸附热ΔHo,吸附熵ΔSo),并根据这些参数详细讨论了缓蚀作用机理.     

织金磷矿在盐酸中的酸解工艺研究

设计了一个4因素5水平正交实验,对磷矿石的盐酸酸解工艺进行了研究,确定了织金磷矿的最佳盐酸酸解工艺.利用正交实验结果分析了酸比、酸质量分数、温度、粒度4种因素对磷矿石中P2O5浸取率的影响.同时得出最佳酸解条件:酸比105％,液固比260％,温度45℃,粒度200目,此时磷矿石中的P2O5的浸取率可以达到98.74％.     

副产蒸汽盐酸合成炉运行总结

介绍副产蒸汽盐酸合成炉的生产工艺,并对生产中出现的点火失败、灯头破裂、装置误连锁停车等问题提出相应解决方案,确保安全生产。     

盐酸生产中空气冷却管的设计

就４０ｔ／ｄ盐酸生产合成炉至石墨冷却器间空气冷却管的设置、管径及管长进行了设计计算。经生产检验设计合理,操作稳定。