低温化学镀镍中络合剂作用研究

研究了络合剂在低温化学镀镍槽液中的作用.试验表明,络合剂的正确选择是低温镇工艺实现的关键,络合剂的稳定性不但影响槽液的稳定,而且对镀速和镀层质量都有重要影响.络合剂的稳定性与其结构及配位原子性质、位阻效应等关系密切.选用复合络合剂,有利于调整镀速与镀层质量.络合剂的缓冲作用对提高镀速有利.     

SPCC钢碱性无氰直接预镀铜工艺研究

目的提高LED支架的性价比,减少SPCC钢表面镀银预镀铜工艺的镀液污染,简化现有的预镀镍-镀铜施镀工艺,提高预镀层质量。方法采用HEDP碱性无氰直接预镀铜方法来简化工艺,用单因素实验法,系统研究了电流密度、镀液pH、电镀温度、HEDP/Cu~(2+)摩尔比、电镀时间等参数,对镀层镀速、孔隙率及镀层表面质量的影响,并表征镀层的微观组织及镀层结合力。结果在阴极电流密度为1.41 A/dm~2,pH值为9.5,温度为50℃,HEDP/Cu~(2+)摩尔比为3.75:1(Cu~(2+)为10 g/L),时间为11 min的条件下,可获得镀速约为1.7 mg/(cm~2·min)的预镀铜层,且镀层与基体的结合力良好,无孔隙,呈良好的光亮/半光亮状的细晶镀层。结论与钢铁表面氰化镀铜及镀银前预镀铜工艺相比,推荐的HEDP直接预镀铜工艺的镀层质量好,可满足直接镀铜和镀银前预镀铜工艺要求,可有效减少镀液污染和简化施镀工艺,对SPCC钢的镀铜工艺改善具有较好的推广价值。     

低浊化学镀镍中络合剂作用研究

研究了络合剂在低温化学镀镍槽液中的作用。试验表明，络合剂的正确选择是低温镀工艺实现的关键络合剂的稳定性不但影响槽液的稳定，而且对镀速和镀层质量都有重要影响。络合剂的稳定性与其结构及配位原子性质，位阻效应等关系密切。     

论大型节能铝电解槽的设计-母线、阴极结构与磁流体稳定性

本文从大型节能铝电解槽的设计出发,介绍了大型化与磁流体稳定性的关系,归纳总结了提高磁流体稳定性的的两个途径,重点分析了阻流技术、降低铝液中水平电流技术、新概念母线设计技术对磁流体稳定性的影响,对超大型节能槽设计标准提出了建议。     

硫酸盐酸性光亮镀锡铋合金工艺

采用赫尔槽试验研究了硫酸盐酸性电镀锡铋合金工艺。以改善镀层的光亮性以及镀液的稳定性为目的,讨论了镀液组分及工艺条件对镀液和合金镀层性能的影响,检测了镀液和镀层的相关性能。结果表明:镀液中加入光亮剂和稳定剂后,可获得一种铋含量达2.5%,且耐蚀性、可焊性优良的光亮Sn-Bi合金镀层。镀液的覆盖能力和分散能力良好,镀液稳定性也得到较大提高。     

大型铝电解槽节能技术的研究与实践

从提高大型槽稳定性和实现深度节能的角度出发,介绍了减少铝液中水平电流技术、新概念母线配置方法、新型阴极结构、新型阳极钢爪组结构以及新一代控制系统,探讨了槽结构整体保温型设计和具体措施,同时对未来我国铝工业技术进步提出了展望。     

焦磷酸钾-HEDP体系无氰仿金电镀工艺研究

在镀液基本组成为焦磷酸钾(260 g/L)、焦磷酸铜(18 g/L)、焦磷酸亚锡(2.0 g/L),电镀工艺条件为电流0.15A,温度30℃,pH=9～10,电镀5 min,和空气搅拌的条件下,利用正交实验探究羟基乙叉二膦酸(HEDP)、酸铜走位剂(AESS)和K_2CO_3对无氰仿金电镀镀层颜色的影响。对正交结果进行分析,最终得出HEDP、AESS、K_2CO_3的最优组合为:HEDP:15 g/L,K_2CO_3:40 g/L,AESS:24×10~(-3)g/L。对以上组合所得到的镀层形貌、厚度、成分、相组成进行。该配方可获得Hull槽试片上全范围光亮的仿金镀层,且镀层表面平整,镀层厚度约为1.5μm。Sn在镀层中主要以Cu_(13.7)Sn的形式存在,且为立方结构。     

羟基亚乙基二膦酸对20SiMn钢在含Cl-混凝土模拟孔隙液中的缓蚀行为

采用电化学技术(动电位极化曲线、自腐蚀电位、EIS以及Mott-Schottky曲线)和表面分析方法(SEM、XPS)研究了羟基亚乙基二膦酸(HEDP)对空冷20SiMn低合金钢在含Cl-的高碱性混凝土模拟孔隙液中的缓蚀作用及机理。结果表明,HEDP对20SiMn钢在含1 mol/L NaCl饱和Ca(OH)2溶液中的缓蚀效果随HEDP浓度的升高存在极值,最佳浓度为1.441×10-4mol/L。在此浓度下HEDP将20SiMn钢的钝性保持时间从6 h延长至9 h,缓蚀效率达到46.45%～59.78%。在发生点蚀的情况下,HEDP对点蚀的发展亦有显著的抑制作用,缓蚀效率超过93%。电化学和表面分析结果表明,HEDP优先吸附在钝化膜表面,通过竞争吸附机制屏蔽了侵蚀性Cl-向钝化膜表面的附着,从而对其产生保护作用。     

HEDP水化学工况与中低压锅炉节能减排技术研究

有机膦酸盐羟基亚乙基二膦酸(HEDP)广泛应用于工业水阻垢缓蚀,在中低压锅炉锅水温度下性能稳定。文章在实验室采用电导法和静态阻垢法以及电化学方法评价了HEDP的阻垢、缓蚀性能,结果表明HEDP浓度为25mg/L时阻垢、缓蚀效果最佳。同时,现场向在用中低压锅炉锅水中投加HEDP,在锅水中建立有机膦HEDP水化学工况,应用结果表明HEDP水化学工况具有投资少、效率高特点,能有效减少锅炉排污,改善锅水水质,提高锅炉热效率,对中低压锅炉的节能减排效果显著。     

Sn(OH)_4对铝型材电解着色的影响及处理方法

<正> 前言自从六年代初日本浅田教授开发了铝及其合金电解着色技术以来,锡盐着色技术在国内应用较为普遍。然而,多年来锡盐着色液的稳定性及再生处理技术一直未得到彻底解决。主盐Sn~(2+)很容易氧化成Sn~(4+),这不仅消耗了槽液的有效成分,而且Sn~(4+)又易发生水解生成氢氧化锡沉淀,使槽液浑浊,加速了槽液的老化,而且,当槽液内Sn(OH)_4积累到一定量后,着色效率和着色质量下降,而且槽液药品消耗量迅速增加,只有除去槽     

Dynamic behaviour of the inhibitor adsorption on gold (111) studied by in situ STM

The study of adsorption/desorption processes of 1‐hydroxy‐ethanol‐1,1‐diphosphonic acid (HEDP) molecules, and the mixture of HEDP/zinc ion on gold surface has been investigated in neutral perchlorate solution using cyclic voltammetry and electrochemical scanning tunnelling microscopy (EC‐STM). Cyclic voltammetry measurements showed that HEDP molecule has an effect on the anodic oxidation of gold. The reversible adsorption/desorption peak in presence of zinc cations is attributed to the effect of zinc ions on the adsorption of HEDP. Results of in situ EC‐STM studies on the initial stages of HEDP adsorption on gold single crystal (111) are presented and compared with the adsorption of the mixture of HEDP/zinc ion. The morphology of the gold (111) surface changed during repeated cycles. Sub‐mono‐layer islands are formed in presence of HEDP molecules. The surface morphology changed significantly in presence of both HEDP and zinc in the solution. After repeated cycles the whole gold surface was covered with a network‐type layer. This adsorbed layer varied in function of the gold (111) potential. The results were analysed and discussed.     

Study of the chemical passivation of iron by phosphonates

The effect of some phosphonic acids (HMEP, NTMP, HEDP) on the chemical passivation of iron by dissolved oxygen in neutral aqueous solutions has been investigated. It has been shown that in the presence of phosphonic acids chemical passivation cannot be attained. This effect is due to the formation of soluble complexes as could be shown by the stability constants determined.     

过氧乙酸中硅酸钠对 Q235 钢的缓蚀影响

目的研究HEDP、十二烷基苯磺酸钠(SDBS)和硅酸钠的复配物在过氧乙酸溶液中对Q235钢缓蚀效率的影响。方法采用静态失重法和动电位极化曲线法,研究常温下在过氧乙酸质量浓度为2000 mg/L的体系中,硅酸钠与HEDP、SDBS复配时对碳钢的缓蚀协同效应,确定最佳配比,分析缓蚀机理。结果 HEDP、SDBS和硅酸钠的复配物,在过氧乙酸溶液中对Q235钢均有一定的缓蚀效果,缓蚀效率依次为:硅酸钠与HEDP硅酸钠与SDBS硅酸钠。当硅酸钠质量浓度为200 mg/L,HEDP质量浓度为100 mg/L复配时,缓蚀效率最高达到90.42%。当硅酸钠质量浓度为200 mg/L,SDBS质量浓度为200mg/L复配时,缓蚀效率最高达到57.76%。单一硅酸钠缓蚀剂的缓蚀效率最高达40.53%。结论硅酸钠能同时抑制阳极和阴极的反应,与HEDP有很好的缓蚀协同效应,硅酸钠与HEDP复配优于与SDBS复配的缓蚀效果。较优复配缓蚀剂为:硅酸钠200 mg/L,HEDP 100 mg/L。     

Role of complexes in inhibition of mild steel by zinc–1-hydroxyethylidene-1, 1-diphosphonic acid mixtures

Abstract

The action of 1-hydrox yethylidene-1, 1-diphosphonic acid (HEDP) in combination with zinc ions as a corrosion inhibitor for mild steel in oxygen containing aqueous solutions has been investigated in relation to the presence of different zinc levels, the presence of aggressive anions, and different pH values. The highest inhibition effect was obtained at a 2·7:1 zinc/HEDP molar ratio, corresponding to 60 ppm zinc, and was associated with a significant anodic effect. In the absence of chloride and with no free forms of the inhibitor components, the zinc-HEDP mixture exhibited good protection over a wide range of pH (6·5-9·5). However, in a weakly acidic medium, protection could not be achieved. Calculations based on the dissociation constants of the HEDP and the stability constants of the possible zinc-HEDP complexes showed that this inhibition can be attributed to the presence of the 2:1 zinc-HEDP complex (Zn₂H_-1L^-) at a sufficient level. It is found that this anionic complex can behave as an anodic, passivating, inhibitor at a concentration as low as 0·00015M (20 ppm zinc-32 ppm HEDP mix ture). This passivity is prevented by the presence of sufficient chloride. The critical chloride concentration in these studies is approximately ten times higher than the complex concentration, in molar terms. It is also found that free phosphonate is aggressive and can prevent passivity due to the preferential formation of soluble iron-HEDP complex. The tolerance of the 2:1 complex to free phosphonate is substantially less than to chloride, approx imately equimolar.     

Laboruntersuchungen zur Korrosion von unlegiertem Stahl in Kühlwässern

Laboratory studies on corrosion of unalloyed steel in cooling waters Corrosion tests were carried out in recycle apparatures to prepare cooling-water treatment. The corrosion behaviour of unalloyed steel St 38b-2 in dependence on m-value of water was tested. The corrosion-inhibiting effect of sodium polyphosphate, zinc sulfate, 1-hydroxy-1,1-diphosphonic acid (HEDP) and the trisodium salt of HEDP and polyacrylate and their combinations in water with m-value 1.0–1.5 mmole per litre was tested in comparison with unalloyed steel. The corrosion rate increases strongly below a m-value of 2.2 mmol per litre. Sodium polyphosphate, sodium polyphosphate/zinc sulfate and zinc sulfate-polyacrylate show good protection features in water with m-value 1.0–1.5 mmole per litre. The trisodium salt of HEDP has an insufficient effect.     

Experimental and theoretical structural analysis of Zn(II)‐1‐hydroxyethane‐1,1‐diphosphonic acid corrosion inhibitor films in chloride ions solution

This work aims to analyze, through weight loss and X‐ray photoelectron spectroscopy (XPS) methods, the inhibitive films of 1‐hydroxyethane‐1,1‐diphosphonic acid (1‐hydroxyethylidene‐1,1‐diphosphonic acid, HEDP) and zinc(II) ions formed on AISI 1020 carbon steel when immersed in solutions containing 30 ppm of chloride ions, 50 ppm of HEDP, and three different concentrations of zinc(II) ions (14, 20, and 30 ppm). Moreover, the results of the experimental surface analyses were compared to molecular modeling studies of the proposed HEDP–Fe(III)/Zn(OH)₂/HEDP–Zn(II) protective film. The film presented dissimilar structures responsible for the different levels of metallic protection for each particular zinc(II) concentration. In general, the increase in Zn(II) concentration leads to more compact and adherent film formation, with decreased corrosion rates of carbon steel.     

Synergistic or additive corrosion inhibition of mild steel by a mixture of HEDP and metasilicate at pH 7 and 11

Electrochemical measurements (steady‐state current‐voltage curves and AC impedance) were coupled with mass‐loss measurements, SEM examinations, and EDSX analyses to investigate the inhibition of corrosion of a carbon steel by a mixture of phosphonic acid HEDP (acid 1, hydroxyethylene, 1‐1 diphosphonic) and sodium metasilicate pentahydrate Na₂SiO₃. 5H₂O in an industrial hard water containing 3.10^?3 M Ca²⁺ ions. At pH 7, HEDP and Ca²⁺ act in a synergistic manner, by formation of a HEDP and calcium containing layer. Addition of silicate at this pH value, allows to reach an efficiency of 94% due to an additive inhibition effect. At pH 11, metasilicate, HEDP, and Ca²⁺ ions reinforce the passive layer in a synergistic way. The mixture (1.7 · 10^?5 M HEDP + 2.6 · 10^‐3 M SiO^2?₃) in the Ca²⁺ containing electrolyte is shown to be able to inhibit efficaciously the corrosion of iron at room temperature, considering uniform corrosion at pH 7 or pitting corrosion at pH 11.     

The Corrosion Resistance of Chromium Electroplated from Trivalent and Hexavalent Chromium Plating Solutions

A comparison has been made of the long term stability and corrosion resistance of trivalent chromium deposited from a chloride based solution and hexavalent chromium deposited from a sulphate based solution. The work showed a difference in corrosion resistance between the two systems and has revealed the corrosion mechanism that caused the failure of the plated films. All the work was carried out on a brass substrate overplated with bright nickel to provide a substrate for the chromium deposit.