Inhibiting Effect of some Monosaccharides on the Corrosion of Copper in Nitric Acid

Abstract

A study has been made of the inhibitive efficiency of some monosaccharides (glucose, fructose, mannose, galactose, in the concentration range 10^?3M–1·0M) on copper corrosion in HNO₃ (0·01, 0·1 and 1·0 M) at temperatures of 15°, 25° and 35°c. It was found that the structures of the various saccharides (pyranosic or furanosic) affected neither the efficiency nor the mechanism of inhibition. Inhibition was practically zero at concentrations of the monosaccharides between 10^?3 and 10^?1 M, whereas, at 1·0 M, 65–70% inhibition was reached in 0·01 and 0·1 M HNO₃, and 50–60% in 1·0 M HNO₃.

In 1·0 M HNO₃ the saccharides act as cathodic inhibitors (reducing HNO₂ present in the HNO₃ solutions), whereas in 0·1 and 0·01 M HNO₃ they also acted as anodic inhibitors through theformation of an organometallic compound with Cu²⁺, which gave slight protection to the metal surface.     

Initial Stages of the Copper Corrosion in Sulfite-Containing Solutions

The initial stages of the formation of phase layers at a copper electrode in solutions containing sulfate and sulfite ions are investigated by the method of quartz microweighing. It is found that the growth of a layer in acidic and neutral solutions proceeds in conformity with a parabolic law. The composition of the surface layer is investigated by x-ray photoelectron spectroscopy. The main component of the layer is found to be Cu₂O. In sulfite-containing solutions, an insoluble sulfite compound of Cu⁺ is also included in the layer.     

Inhibitive Efficiency of some Substituted Thioureas for the Corrosion of Aluminium in Nitric Acid

Abstract

The inhibitive efficiencies of thiourea and some of its derivatives have been studied in relation to the corrosion of aluminium (Grade 1060) in nitric acid at 25°c, 35°c and 45°c. The efficiency in 20% HNO₃ at 25°c decreases in the order: p-chlorophenyl thiourea > m-chlorophenyl thiourea ≥ o-chlorophenyl thiourea ≥ phenyl urea > 1:3 di-phenyl thiourea ≥ 1:3 di-p-chlorophenyl thiourea. ≥ 1:3 di-m-chlorophenyl thiourea > thiourea. The adsorption of the compounds is in agreement with Langmuir's adsorption isotherm equation up t a concentration of 250 ppm, at all the three temperatures studied. The percentage efficiencies of the inhibitors were found to increase with increase in temperature from 25° to 45°c. There is no relation between the relative efficiencies of the inhibitors and their critical current densities or primary passivation potentials. All the inhibitors were found to act predominantly on local cathodes although partially effective on the anodes.     

三唑化合物在1mol/L盐酸中对碳钢的缓蚀作用研究

合成了一种新型三氮唑化合物：1-（3-（4-氟苯基）-4,5-吡唑基-2-（1,2,4-三唑基）乙酮,并通过失重实验、动电位极化、交流阻抗及扫描电镜方法研究了其在1mol／L盐酸溶液中对Q235碳钢的缓蚀效果。结果表明,该三唑化合物在1mol／L盐酸中对Q235碳钢有较好的缓蚀效果,是混合型缓蚀剂,该缓蚀剂在碳钢表面的吸附符合Langmuir等温吸附式。     

盐酸溶液中烷基咪唑啉对铜的缓蚀行为

采用了电化学阻抗、极化曲线和循环伏安等方法研究了2-十一烷基-N-羧甲基-N-羟乙基咪唑啉(UHCI)在5%HCl溶液中对铜的缓蚀行为。结果表明,UHCI对铜有明显的缓蚀作用,随着缓蚀剂浓度的增加,其缓蚀率增大,但当缓蚀剂质量浓度达到0.15%后,再增加缓蚀剂浓度,缓蚀效率不再提高;该缓蚀剂是一种混合型缓蚀剂,同时抑制了阴极还原和阳极氧化过程。量子化学计算结果表明,缓蚀剂分子主要通过O(14)提供电子与金属原子成键,在金属表面发生化学吸附。     

The Rectification of Faulty Acid Copper Solutions

The morphology of pits in decorative nickel+chromium coatings resulting from service corrosion in an industrial atmosphere has been compared with that of pits produced in accelerated corrosion tests. Corrosion in the three accelerated tests examined and in the early stages of service corrosion was frequently characterised by formation of hemispherically shaped pits in the nickel layer: these occurred at discontinuities in the chromium top-coat. In the later stages of service corrosion, say, after several years’ exposure, pits were more often of irregular shape. In copper+nickel+chromium coatings, none of the accelerated tests gave close reproduction of the type of pit produced by corrosion in service. In double-layer nickel+chromium coatings, however, the type of pitting experienced in service was reasonably well reproduced by the acetic acid/salt spray and the Corrodkote tests, but not by the SO₂ test. In order to obtain a better appreciation of the electrochemistry of the pitting corrosion observed, measurements were made of the anode polarisation characteristics of electrodeposited nickel and copper foils and of wrought steel, in electrolytes simulating those used in the accelerated corrosion tests. The results of these measurements are discussed in relation to the metallographic observations.     

某铜冶炼烟气制酸装置耐酸蝶阀的腐蚀失效分析

通过现场工况调研、化学成分分析、组织形貌观察和电化学测试等手段分析了耐酸碟阀腐蚀的原因。结果表明:局部腐蚀穿孔和腐蚀坑主要是由铸件缺陷所引起的,而阳极保护系统引起的电解腐蚀是导致严重均匀腐蚀的主要原因。     

Inhibitive Effect of an Onium Compound on the Dissolution of Steel in Hydrochloric Acid

Abstract

An onium compound has been found to be an effective inhibitor for the dissolution of mild steel in hydrochloric acid in all practical conditions. Adsorption studies based on weight loss measurements show that adsorption of onium obeys the Freundlich adsorption isotherm. Rectilinear Arrhenius plots were obtained both in the presence and absence of inhibitor, but the activation energy is(paradoxically) much lower in the presence of the inhibitor. Onium polarises both the anode and cathode, the extent of the polarisation increasing with inhibitor concentration. The exchange current is considerably reduced in the presence of the inhibitor, inhibitor efficiencies calculated from this reduction agreeing well with values calculated from weight loss measurements. The combined use of KI and onium shows a synergistic effect.     

氨基酸类绿色酸洗缓蚀剂的研究进展

氨基酸类缓蚀剂具有无毒、可生物降解、价格低、纯度高等特点,是一类很有发展潜力的绿色缓蚀剂.本文总结了国内外氨基酸类缓蚀剂在酸性介质中的研究进展,探讨了它们的缓蚀作用机理,并对其发展趋势进行了展望.     

Peculiarities of the Contact Electric Resistance of Copper in Perchloric Acid Solutions

The contact electric resistance (CER) of polished copper specimens in 0.003 to 1 N perchloric, sulfuric, and hydrochloric acid solutions and their mixtures is studied. The CER of copper in perchloric acid is shown to substantially exceed that in hydrochloric and sulfuric acids. Small sulfate and chloride additives to perchloric acid solutions prevent the adsorption and reduction of perchlorate ions. A conclusion on the reduction of perchlorate ions on copper is made and a supposition that the high CER values of copper in perchlorate solutions are determined by the adsorption of oxoions, which are intermediate products of the perchlorate reduction, is put forward. A relation between the adsorption of oxoions on copper, silver, platinum, and gold and their electrocatalytic activity is considered.     

Inhibition by some Thiocompounds of the Corrosion of Copper in Monochloracetic Acid Solution

Abstract

The inhibitory action of ethanolthiol, 2-mercaptoethanol and dodecyl mercaptan towards the corrosion of copper (99·8 %) in 0·1 M monochloracetic acid has been investigated. The inhibitive efficiency of these compounds may be arranged in the following order: dodecyl mercaptan > 2-mercaptoethanol > ethanolthiol. Polarisation measurements indicated that the compounds were principally cathodic corrosion inhibitors. I.R. spectra of the protective film formed on copper in solution inhibited with 2-mercaptoethanol, and of the pure chelate synthesised from 2-mercaptoethanol and copper ions in solution, were found to be identical.     

New Corrosion Inhibitors for Low-Carbon Steel in Hydrochloric Acid Solutions

Protection of Metals and Physical Chemistry of Surfaces - Abstract—The effects that indolizine derivatives, a tellurium organic compound, rhodanine, sodium diethyldithiocarbamate, and some of...     

铜对铬锰不锈钢耐蚀性的影响

采用失重法、电化学极化曲线法、SEM、EDS、XRD等分析手段,分析了铜对铬锰不锈钢耐蚀性的影响及其机制。结果表明:随着铜加入量的增加,不锈钢表面产生的氧化膜变得致密,不锈钢的腐蚀减缓,耐蚀性提高。铬锰钢中的铜,以Cu2+形式在表面还原富集,降低不锈钢的活性溶解速度,有效地促进了不锈钢钝化膜的形成,从而显著提高其在稀硫酸中的耐腐蚀性能。     

2205双相不锈钢在硫酸中的腐蚀性能

采用腐蚀浸泡失重方法结合动电位极化曲线和电化学阻抗谱,研究了不同温度下2205双相不锈钢在不同浓度H2SO4溶液中的耐蚀性,并与传统的20R钢和316L不锈钢作对比。结果表明,三种材质的耐蚀能力由强到弱排序为:2205316L20R;硫酸浓度和温度对腐蚀速率的影响由强到弱排序都为:20R316L2205。在T≤40℃,2205双相不锈钢的腐蚀深度为0mm/a,耐蚀性等级为1级,评定为完全耐蚀;当温度增加至60℃且硫酸浓度为30%时,其腐蚀速率显著增加,腐蚀深度为27.026mm/a,耐蚀性等级为10级,评定为不耐蚀。高铬含量可以降低不锈钢材料的钝化电位,另一方面可以增强不锈钢表面钝化膜的修复能力,可能是2205双相不锈钢比316L和20R更耐蚀的本质原因。     

Inhibition Effect of Thallium Cations on Aluminum Corrosion in Hydrochloride Solutions

The effect of contact thallium deposition on the corrosion rate of aluminum in hydrochloride solutions is studied. When a fraction of “metal” depolarization of aluminum corrosion is insignificant, the corrosion rate depends on the aluminum surface coverage with thallium deposit and the time. Partial inhibition coefficients, which are associated with the variations in the free-corrosion potential (K _ΔE ) and in the fraction of aluminum surface area occupied by thallium deposit (K _s ), are calculated. The variations of partial inhibition coefficients K _s and K _ΔE with the variations of thallium iodide concentration and the corrosion test time are analyzed. __________ Translated from Zashchita Metallov, Vol. 41, No. 5, 2005, pp. 467–472. Original Russian Text Copyright ? 2005 by Bartenev, Barteneva.     

Synergistic Effect between Fragaria ananassa and Cucurbita pepo L Leaf Extracts on Mild Steel Corrosion in Hydrochloric Acid Solutions

Protection of Metals and Physical Chemistry of Surfaces - The thermodynamic, inhibitive and synergistic properties of Fragaria ananassa (strawberry) and Cucurbita pepo L (zucchini) leaf extracts on...     

On the Nature of the Effect of Copper on the Corrosion Resistance of Iron

Sections of the Fe–Cu–O system diagram and based on them potential–pH diagrams of the Fe–Cu–H₂O general system and the system ferrite of 12 steel + copper inclusions (-phase)–H₂O are constructed for 25°C. Thermodynamic peculiarities of the effect of copper on the chemical and electrochemical stability of iron alloys are discussed. At an ordinary content in steel (tenths of percent), copper not only performs the function of an alloying addition, but also enters into a mixed spinel based on magnetite in the form of CuFe₂O₄, thus enhancing the density and protective properties of the passive film.