溴化十六烷基吡啶自盐酸溶液中在铝表面上的吸附及其缓蚀作用

用失重法研究了溴化十六烷基呲啶对铝在盐酸溶液中的缓蚀作用, 应用吸附理论和Sekine方法处理实验数据~[4], 发现溴化十六烷基吡啶自盐酸溶液中在铝表面上产生了吸附, 且基本服从Langmuir吸附等温式。求得吸附热为35.4 kJ mol~(-1), 认为这种吸附是产生缓蚀作用的重要原因。实验还表明, 缓蚀率随温度升高而增大, 根据这些结果讨论了吸附与缓蚀作用之间的关系。     

阳离子表面活性剂共振散射法测定海藻酸钠

在HAc-NaAc缓冲溶液中,海藻酸钠(SA)能与某些阳离子表面活性剂(CS)如溴代十六烷基吡啶(CPB)、氯代十六烷基吡啶(CPC)、氯代十四烷基吡啶(TPC)在静电引力和疏水力的作用下结合形成离子缔合物,使得体系的共振散射(RS)信号急剧增强并产生新的RS光谱。在优化实验条件下,当海藻酸钠的浓度分别在0.010~2.0,0.10~1.6和0.20~2.0μg/mL范围内时,各体系的共振散射强度变化值(%I)与海藻酸钠浓度之间均有良好的线性关系,其检出限分别为0.0414,0.0457和3.01 ng/mL。     

磷酸溶液中DDA在锌表面的吸附及其缓蚀作用

采用失重法及电化学法研究了锌在含或不含十二烷基胺（DDA）的磷酸溶液中的腐蚀作用，得出相应的动力学方程，求得有关的动力学及热力学参数.用光电子能谱（XPS）检测发现，在40～70 ℃区间，锌在磷酸溶液中生成Zn(OH)x覆盖层，表现出较强的自缓蚀效果，而在30～40 ℃区间，因DDA以及, 等微粒同时吸附在锌表面，DDA在磷酸溶液中表现出较强的缓蚀作用.用吸附理论讨论了这种缓蚀作用产生的原因.     

新试剂4，4'-(2-氯-4-硝基重氮氨基)联苯与氯化十六烷基吡啶显色反应的研究

研究了4,4'-(2-氯-4-硝基重氮氨基)联苯与阳离子表面活性剂氯化十六烷基吡啶发生显色反应,提出了光度法测定氯化十六烷基吡啶的新方法。实验结果表明,在碱性介质中,4,4'-(2-氯-4-硝基重氮氨基)联苯与氯化十六烷基吡啶形成1：2紫红色离子缔合物,最大吸收波长位于570 nm处,表观摩尔吸光系数为2.16×104...     

DTAB-KTL复合添加剂抑制锌电极腐蚀的协同效应

应用失重法、电化学方法、扫描电镜等研究十二烷基三甲基溴化铵(DTAB)、咳特灵(KTL)复合添加剂抑制锌在KOH(3mol/L)溶液的缓蚀作用.结果表明:与单一添加剂相比,DTAB-KTL复合添加剂缓蚀效果更好.由于二者的协同效应,使KTL更容易吸附在锌电极DTAB表面,提高缓蚀作用.     

正十六烷基磺酰氯的合成

正十六烷醇经亚磺酰甩作用转换成1－氯代正十六烷,在相转移催化剂条件下,1－氯代正十六烷和硫脲进行亲核反应,合成正十六烷基异硫脲盐酸盐,并以此为中间体用氯气氧化法制备正十六烷基磺酰氯,纯度大于95％,总收率为67％。     

溴代十六烷基吡啶对冷轧钢在三氯乙酸中的缓蚀性能

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)及扫描电子显微镜(SEM)研究了阳离子表面活性剂溴代十六烷基吡啶(HDPB)在0.10 mol·L^-1 Cl₃CCOOH溶液中对冷轧钢(CRS)的缓蚀性能。结果表明：20℃时100 mg·L^-1 HDPB的最大缓蚀率可达93.7%,HDPB浓度越高,缓蚀性能越强,而温度越高,缓蚀性能越弱。HDPB在CRS表面的吸附过程包含了物理吸附和化学吸附,符合Langmuir吸附等温式,且为放热吸附。冷轧钢在添加HDPB的Cl₃CCOOH溶液中腐蚀速率随温度的变化规律符合Arrhenius和过渡态理论方程,添加HDPB后表观活化能、指前因子、表观活化焓、表观活化熵均增大。HDPB为混合型缓蚀剂,其电化学作用机理为“几何覆盖效应”,加入HDPB后,Nyquist图主要由高频区的容抗弧组成,且随着HDPB浓度增大,电荷转移电阻增大,SEM微观形貌进一步证实了HDPB有效减缓了CRS表面的腐蚀速度。     

气-液界面上十六烷基溴化吡啶水溶液动态表面张力的研究

滴体积法测定了十六烷基溴化吡啶溶液的动态表面张力。考察了浓度、温度对动态表面张力的影响。讨论了十六烷基溴化吡啶分子在气／液界面上的吸附动力学,发现吸附遵从扩散-动力学控制机理．从表观扩散系数计算了吸附能垒,分析了吸附能垒存在的原因。     

云南沱茶自水溶液中对铈(Ⅳ)离子的富集作用

研究了云南沱茶在不同浓度、温度、pH条件下, 自水溶液中吸附Ce(Ⅳ) 离子的特性, 并分别讨论了阴离子表面活性剂十二烷基硫酸钠(SDS), 阳离子表面活性剂氯代十六烷基吡啶(CPC) 和非离子表面活性剂聚乙二醇辛基苯基醚(OP) 对沱茶吸附Ce(Ⅳ) 离子的影响, 结果表明, 在一定条件下, 沱茶对铈(Ⅳ) 的吸附量可达7.95 mg*g-1, 吸附规律符合Langmuir等温方程, 计算了吸附热, 对沱茶吸附Ce(Ⅳ) 离子的机理进行了讨论.     

电位滴定氟硼酸根的新滴定剂

Smith曾用四苯氯化鉮(TPA)电位滴定BF_4~-,但因沉淀溶解度较大,必须在低温(2℃)滴定,操作不便。Selig提出氯代十六烷基吡啶(CPC)和十六烷基三甲基氯化铵(CETAC)作滴定剂,我们观察到过量F-有严重干扰。本文报导节基十四烷基二甲基氯化铵(BDTAC)可在F-介质中作为电位滴定BF_4~-的滴定剂,用于硼铁中高含量硼的测定,能获良好结果。     

电流密度对锌电积用Pb-Ag平板阳极电化学行为的影响(英文)

研究了在不同电流密度下进行长时间极化后Pb-Ag(0.8%(质量分数,w))平板阳极的阳极电位、腐蚀率及阳极钝化膜.同时,也研究了该阳极在ZnSO4-MnSO4-H2SO4电解液中的阴极电流效率和阴极锌品质.阳极钝化膜的表面形貌用扫描电镜(SEM)进行观测.实验结果表明,不管电解液中是否存在Mn2+,电流密度对阳极和阴极的电化学行为都产生了显著的影响.随着电流密度的升高,阳极电位、腐蚀率、阴极电流效率和阳极泥生成量也增加,而阴极锌中的Pb含量则减少.当电流密度从500A·m-2降到200A·m-2时,阳极在ZnSO4-MnSO4-H2SO4电解液中的稳定电位和腐蚀率分别减少64mV和40%.此外,在比较低的电流密度下,阳极电位更容易稳定,阳极表面生成的钝化膜更加致密并与基体结合牢固,这些都有利于降低阳极腐蚀率.为了降低阳极电位、减小阳极腐蚀率及阳极泥生成量并提高阴极电流效率和阳极锌品质,锌电积的理想工作条件是较低的阳极电流密度和较高的阴极电流密度.     

Study on corrosion resistance of electroplating zinc–nickel alloy coatings

Electrodeposited zinc–nickel alloy coatings have been widely adopted for surface treatment of automobile body steel sheet for high corrosion resistance. The corrosion behavior of the coatings has been related with the components of nickel, and the zinc–nickel alloy passive coatings have much higher corrosion resistance than that of zinc–nickel alloy coatings. In the present paper, the corrosion resistance behavior of the zinc–nickel alloy coatings obtained by new process and formulation has been studied by means of the electrochemistry test and neutral salt spray test. And it is discovered that the properties of corrosion resistance of zinc–nickel alloy passive coatings were better than that of zinc passive coatings, Cadmium passive coatings and alloys of electrodeposited cadmium–titanium. The components of corrosion productions, in terms of X‐ray diffraction (XRD), are mainly ZnO, ZnCl₂ · 4Zn(OH)₂ and small quantity of 2ZnCO₃· 3Zn(OH)₂. The component of zinc–nickel alloy coatings has been investigated with Glow Discharge Optical Emission Spectrometry (GDA‐750). And it is found that as the thickness of zinc–nickel alloy coatings increases, the component of zinc increases from beginning to end, but the peak value of nickel appears and an enrichment of nickel in the coatings comes into being. Because the electrodeposited zinc–nickel alloy coatings exhibit different alloy phases as a function of their alloy composition, in this paper, the crystal structure changing with the different component of nickel has been studied in terms of XRD. The result shows that electrodeposited zinc–nickel alloy has different phases: α‐phase, a solid solution of zinc in nickel with an equilibrium solubility of about more than 79% nickel; γ‐phase, an intermediate phase with a composition Ni₅Zn₂₁; η‐phase, a solid solution of nickel in zinc with less than 5% nickel; and δ‐phase (Ni₃Zn₂₂) appeared from η‐phase to α‐phase with increasing content of nickel. Copyright © 2009 John Wiley & Sons, Ltd.     

Ecofriendly new nanocomposites coating formulation of zinc reinforced with calcium oxide nanoparticles synthesis from oyster shell

The zinc coating of mild undergoes rapid corrosion for a short period of time in harsh environments. This affects the durable life and overall performance of the zinc coatings. The electrochemical, oxidation, and wear performance, as well as the surface morphological properties of new nanocomposites coating formulations of zinc reinforced with calcium oxide nanoparticles, were studied in order to improve the corrosion and wear performance of zinc coatings. A current density of 1.5–2.0 A/cm² was used for the electrodeposition. The wear, oxidation, hardness, corrosion rate, and morphological properties were evaluated. The characterization of these composite coatings showed low wear rates and higher corrosion and oxidation resistance. At 1.5A/cm² current density, a 65.53% enhancement in the hardness values and 57.14% oxidation protection were obtained. The smaller crystallite size of the deposited sample is the main reason for the lower corrosion and wear resistance and higher hardness values obtained. It was established that waste oyster can be used for the electrodeposition of mild steel to enhance corrosion resistance and hardness values. CaOnp made from oyster shells has been shown to make mild steel more resistant to corrosion, wear, and oxidation.     

新型单丝电极交流探头在3.5wt.% NaCl中的电化学响应规律研究

本文应用新研发的一种无参比无辅助的单丝电极交流探头技术,研究碳钢和锌金属丝电极在3.5wt.% NaCl中的电化学腐蚀规律和牺牲阳极保护行为. 通过与传统的三电极电化学交流阻抗结果的对比和分析,进一步证明了该新型探头具有简便、快速、准确、稳定的特性,可实现定量评估. 测量显示,在3.5wt.% NaCl中,碳钢的瞬时腐蚀速率及累积腐蚀失重大于锌,它们腐蚀行为的差异与表面膜的性质及变化有关. 在碳钢-锌电偶对中,锌的保护效率可达到95%以上,且随浸泡时间增加先增加后减小.     

锌合金阳极在不同pH值Ca(OH)_2溶液中的电化学行为

应用恒电位法测定锌合金阳极在不同pH值的Ca(OH)2溶液中的极化曲线,X-射线衍射分析了该锌合金阳极的腐蚀产物.实验表明:在不同pH值的碱性溶液中锌合金阳极表现出完全不同的电化学行为:在不稳定钝化区内出现了3个零电流电位;根据锌合金阳极在Ca(OH)2溶液中极化曲线测定了活化区内各不同pH值下的零电流电位、腐蚀电流密度,以及钝化区间内的维钝电流密度、钝化膜破裂电位等电化学参数;绘制电位-pH图,并与纯锌-水系的电位-pH图进行比较.     

Electrolessly Plated Ni-Zn（Fe）-P Alloy and Its Corrosion Resistance Properties

The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and the molar ratio of NiSO4/ZnSO4 on the deposition rate and the composition of deposits have been studied. It was found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. The structure and the surface morphology of Ni-Zn(Fe)-P coatings were characterized with XRD and SEM, respectively. The alloys plated under the experimental conditions consisted of an amorphous phase coexisting with a crystalline cubic Ni phase (poly-crystalline). The surface morphology of the coating is dependent on the deposition parameters. The corrosion resistance of the Ni-Zn(Fe)-P deposits was examined via mass loss tests and anodic polarization measurements, respectively. The results show that the surface morphologies of the deposits and the corrosion resistance of the deposits have been improved. The results of mass loss tests almost accord with those of anodic polarization measurements. The corrosion mechanisms of Ni-Zn(Fe)-P alloys in NaCl and NaOH solutions were investigated by means of EDX. The deposit immersed in an NaCI or an NaOH solution contains more content of oxygen and less contents of the metals(except Fe) than that placed in air, which shows that the NaCl or NaOH solution can accelerate the oxidation of the deposit.     

Phosphatation of iron powder metallurgical samples for corrosion protection

Recently, powder metallurgy methods have been used widely for industrial purposes. In this work, powder-metallurgically produced samples were selected for zinc phosphate coating. Zinc phosphate coating was performed at 50 and 70 °C for 20 min in a bath containing 10 g l^?1 ZnO, 25.5 g l^?1 H₃PO₄, 5.88 g l^?1 HNO₃, and 2 g l^?1 NaNO₃. The effect of temperature on the phosphating process has been studied. The structure and corrosion resistance of coats have been investigated using scanning electron microscopy (SEM) and electrochemical methods (polarization and EIS). Results show that an increase in temperature affects the crystalline structure of the coats. The formation of the zinc phosphate coat on the powder metallurgical samples significantly decreases the corrosion rate of the samples.     

A study of thin surface layers by multilayer Mössbauer spectroscopy /MMS/

A stacking Mössbauer technique, MMS has been applied for studying thin surface layers. The surface layers formed on the⁵⁷Fe film in aqueous solutions of corrosion inhibitors, such as zinc phosphate and barium metaborate, and in distilled water was studied by this method. It has been found that the corrosion is much slower in the presence of zinc phosphate and barium metaborate. XPS analysis suggests the formation of a mixed iron zinc phosphate on the surface of the⁵⁷Fe film after corrosion in a zinc phosphate solution.     

镍-磷-锌盐纳米复合化学镀层抗腐蚀性能的研究

镍-磷-锌盐纳米复合化学镀层抗腐蚀性能的研究