盐酸介质中脱氢松香基咪唑啉缓蚀剂对Q235钢缓蚀性研究

利用静态失重法测定了脱氢松香基咪唑啉系缓蚀剂在盐酸介质中Ｑ２３５碳钢的缓蚀速度和腐蚀效率。研究Ｑ２３５钢在盐酸介质中的腐蚀动力学特征,求出了腐蚀速度方程及相关动力学参数。结果表明,作为一种吸附型有机缓蚀剂,脱氢松香基咪唑啉在盐酸中对Ｑ２３５钢具有较强的缓蚀能力,且缓蚀效率随温度升高而增大。     

Use of the polarisation shift criterion to evaluate cathodic protection of on-grade steel storage tanks

The cathodic protection (CP) of on-grade coated steel storage tanks deployed on reinforced concrete slabs in soils of 20–30?kΩ?cm resistivity was evaluated for two different time periods 9 years apart. The required CP current was calculated and the ohmic drop was measured using the instant-off potential method. The resulting polarisation shift is a useful indicator of the level of protection afforded and whether the potential criterion or the polarisation shift criterion is fulfilled. It was also noted that the greater the ground resistivity, the less corrosive the environment for an on-grade steel structure.     

Corrosion behaviour of carbon steel,titanium and titanium alloy in simulated underground water in Beishan area preselected for nuclear waste repository in China

The groundwater will completely infiltrate to the surface of nuclear waste container after the closure of its deep geological disposal. Therefore, the corrosion behaviour of Q235 carbon steel, titanium and titanium alloy, which were the candidates as the container materials for high-level nuclear waste disposal in simulated groundwater solution of Beishan to be served as the preselected high-level nuclear waste disposal area in China at different temperatures, was studied through electrochemical methods including open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarisation curve measurements. The results show that the corrosion rate of titanium and titanium alloy is lower than that of carbon steel at all temperatures, and they are more promising as container materials. Another phenomenon is that higher temperatures facilitate the protection performance of corrosion products compared with lower temperatures.     

低碳钢基体上电沉积聚苯胺膜及耐蚀性研究

在草酸溶液中．采用恒电流阳极电解法在低碳钢上制备了聚苯胺膜层，该电解过程主要包含金属活性溶解-钝化-聚苯胺膜聚合沉积等三个先后发生的步骤。所得聚苯胺膜呈蓝绿色，均匀致密，与低碳钢基体的结合较好。在氯化钠溶液中的电化学测试表明，聚苯胺膜的存在可以显著地提高低碳钢的耐腐蚀性和抗点蚀能力。     

金相试样制备过程概述

介绍了用于微观观察检验的样品——金相试样的制备过程:取样、镶嵌、磨光(粗磨和细磨)、抛光、腐蚀,以及每个过程所要注意的事项等。金相制样的好坏直接影响着检验结果的正确与否,在极端情况下,不正确的操作可能造成假组织,从而得出错误的结论。所以金相制样过程尤其重要。     

On the corrosion inhibition of low carbon steel in concentrated sulphuric acid solutions. Part I: Chemical and electrochemical (AC and DC) studies

The influence of the concentration of adenine (AD), as a safe inhibitor, on the corrosion of low carbon steel (LCS) in aerated 4.0 M H₂SO₄ solutions was studied. The investigations involved weight loss, potentiodynamic polarization, impedance and electrochemical frequency modulation (EFM) methods. Variations of open-circuit potential (OCP) as a function of time till steady-state potentials were also studied. Measurements were conducted under the influence of various experimental conditions complemented with ex situ EDX examinations of the electrode surface. By using EFM measurements, corrosion current density was determined without prior knowledge of Tafel slopes. Results obtained revealed that together with iodide ion, AD is an effective corrosion inhibitor for LCS corrosion in H₂SO₄ solutions. Synergism between iodide ion and AD was proposed. Potentiodynamic polarization studies showed that AD alone and the mixture of AD and iodide ions act as mixed-type inhibitors for the corrosion of LCS in 4.0 M H₂SO₄ solution. The inhibition mechanism involves the electrostatic adsorption of protonated AD molecules on the LCS surface charged with a negative layer of chemisorbed I⁻ ions. An adherent layer of inhibitor is postulated to account for the protective effect. EDX examinations of the electrode surface confirmed the existence of such adherent layer on the electrode surface. The inhibition efficiency increases with increase in the concentration of AD and immersion time. The potential of zero charge (PZC) of the LCS electrode was determined in 4.0 M H₂SO₄ solutions in the absence and presence of 0.001 M KI, and the mechanism of adsorption was discussed. The results obtained from chemical and electrochemical measurements were in good agreement.     

Study of corrosion behaviour of A106 carbon steel absorber for CO2 removal in amine promoted hot potassium carbonate solution (Benfield solution)

The CO₂ absorber is one of the largest pressure vessels in ammonia plants, which are suffering from severe corrosion problems worldwide. The aim of the present study is to examine the corrosion behaviour of A106 carbon steel absorber for CO₂ removal in amine promoted hot potassium carbonate solution (Benfield solution). This study simulates CO₂ removal unit in ammonia production process at Abu Qir Fertilizers and Chemical Industries Company (Alexandria, Egypt) and many other plants all over the world. A typical Benfield solution contains hot potassium carbonate K₂CO₃, potassium bicarbonate KHCO₃, diethanol amine (DEA) as a promoter and potassium metavanadate KVO₃ as corrosion inhibitor. The rate of galvanic corrosion of carbon steel absorber/stainless steel pall packings couple in Benfield solution was measured without adding the corrosion inhibitor KVO₃ in order to measure the influence of corrosive solution. The corrosion rate was measured by weight loss technique in relation to different operating parameters such as solution velocity, solution temperature, %K₂CO₃, CO₂ loading, %DEA and the effect of the presence of solution contaminants. In general, increasing solution velocity, solution temperature, %K₂CO₃, CO₂ loading and the presence of solution contaminations increase the corrosion rate. However, the increase in %DEA in solution decreases the corrosion rate. The strong dependence of corrosion rate on both solution and gas velocities indicates the diffusion controlled nature of the corrosion process. In addition, estimation of activation energy revealed a value of 4·8 kcal mol^?1. Surface morphology study depicted the presence of a porous solid film of corrosion products on carbon steel surface. It has been found that the liquid phase diffusion of bicarbonate to the steel solution interface is the rate determining step.     

Kinetic study of effect of amine based corrosion inhibitor in reducing corrosion rate of 1018 carbon steel in seawater solution

Abstract

The effect of an amine based inhibitor (CORTRON AR-505) on the corrosion of 1018 carbon steel in seawater was studied using weight loss, adsorption isotherm analysis, polarisation resistance and potentiodynamic polarisation techniques. AR-505 is adsorbed on the steel surface according to the Shawabkeh–Tutunji adsorption isotherm equation. A maximum adsorption capacity of 0·097 mg AR-505 was obtained to cover a monolayer of adsorption. Corrosion kinetics illustrated that inhibition efficiency has increased with increasing inhibitor concentration and solution pH, while it decreased with increasing solution temperature and stirring speed. Polarisation data fitted by the Butler–Volmer equation showed that the values of anodic and cathodic transfer coefficients are in the average of 0·84 and 0·15 respectively. Corrosion resistance measurements provided a rapid decrease in corrosion rate from 7 to 1 mm/year.     

低合金钢涂覆类金刚石膜耐蚀性能测试

用自制的多功能离子束辅助沉积设备在20Cr和40Cr低合金钢上沉积类金刚石膜，通过失重法，电化学方法研究低合金钢镀膜前后在不同腐蚀介质中的耐蚀行为，实验结果表明，低合金钢沉积类金刚石膜后，腐蚀速度降低，其抗全面腐蚀的性能与2Cr13不锈钢接近，而且类金刚石膜显著提高了低合金钢基抗点蚀的能力，失重法和稳态极化曲线法所得结果吻合。     

不锈钢在海洋环境中的腐蚀

在海洋大气区含铬大于１７％的不锈钢基本不腐蚀,在飞溅区,在含铬大于１７％的不锈钢腐蚀较轻,耐蚀性没有明显的差别。２Ｃｒ１３在海洋大气区和飞溅区不能维持钝态。不锈钢在潮 汐区的腐蚀较重,耐蚀性有明显差别。不锈钢在全浸区的腐蚀业重,耐蚀性判别很大。海生物污损对不锈钢的腐蚀有明显的影响。     

变异硫酸盐还原菌(SRB)对碳钢腐蚀行为的影响

研究了变异硫酸盐还原菌（SRB）对碳钢腐蚀规律,变异SRB菌及原始菌的腐蚀对比实验表明,耐碱菌对碳钢腐蚀最严重,其次是耐酸菌,两者均大于原始菌,用扫描电子显微镜和电子探针对腐蚀产物和腐蚀后碳钢基体表面进行分析,耐酸菌对碳钢的腐蚀,腐蚀产物以菌落形式聚集在一起,其基体表面有明显的大小不同的点蚀斑,耐碱菌对碳钢的腐蚀,与原始菌腐蚀产物形态相比更均匀一些,其基体表面的点蚀斑较小且分布比较均匀。     

HCl-H2O-CMS体系对20#钢腐蚀的现场分析

对CMS(甲烷氯化物)生产工序中20#钢的现场腐蚀情况进行了统计,探讨了HCl-H2O-CMS体系对20#钢的腐蚀规律及其机理。调查分析认为,HCl-H2O-CMS体系对20#钢腐蚀的主要影响因素是体系中HCl和H2O的含量,同时对采集数据拟合了腐蚀速率方程。最后针对该体系腐蚀的现象和特征,对操作工艺、部件材料及结构等进行了改进,实际应用后取得了良好的效果。     

A comparative study of molybdate/silane composite films on galvanized steel with different treatment processes

Two types of molybdate/silane composite films were obtained on the surface of hot-dip galvanized steel sheets by either directly immersing in a solution containing silane and molybdate as additive (single-step process), or firstly immersing in a molybdate solution, then in a silane solution (two-step process). The chemical compositions and microstructures of the films were examined by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and reflection absorption infrared spectroscopy (RAIR). The corrosion resistances were investigated by electrochemical measurements and neutral salt spray (NSS) test. The results showed that the molybdate/silane composite film formed in the single-step process had a similar double-layer structure as that obtained in the two-step process. The inner layer was composed mainly of the elements O, Mo, Zn, and P, similar to the single molybdate film; whereas the outer layer was composed mainly of the elements C, O and Si, similar to the single silane film. Compared with the single molybdate or silane film, the corrosion current of the composite films was reduced and the impedance of the films was increased. Accordingly, the corrosion resistance of the composite films was remarkably enhanced to a level which was comparable to or even surpassing that of the conventional chromate passivation film.     

超声波测厚技术在埋地管道局部壁厚抽检中的应用

介绍了利用超声波测厚技术进行埋地管道壁厚抽测的检测、评价方法,举例说明了该技术在胜利油田的应用情况。结果表明,该方法数据采样准确,评价结果可靠,为指导无法实施内检及不适宜应用非开挖外检测的埋地管线的运行、维护、维修与更换提出了科学公正的检测数据与评价结果。     

不锈钢储罐在酸雾环境中的腐蚀及其防护方法

分析了奥氏体不锈钢在盐酸酸雾环境中的腐蚀机理,采取了有效的防护措施,使腐蚀得到控制.     

00Cr24Ni6Mo2N双相不锈钢耐腐蚀性能分析

00Cr24Ni6Mo2N不锈钢是双相不锈钢，在正常情况的组织中有α铁素体相和γ奥氏体相，各占约50％。经分析它的击破电位(Eb)、保护电位(Ep)及室内加速腐蚀试验和海港挂片试验，都证实它具有优良的耐点蚀性能。经测试它同时具有良好的耐应力腐蚀和耐冲刷腐蚀能力。     

Electrochemical and analytical study of corrosion inhibition on carbon steel in HCl medium by 1,12-bis(1,2,4-triazolyl)dodecane

1,12-bis(1,2,4-triazolyl)dodecane (dTC12) is an excellent corrosion inhibitor for carbon steel in deaerated 1 M HCl solution. In this work electrochemical and analytical techniques were used to study the inhibition of corrosion on carbon steel in acidic medium. The carbon steel corrosion inhibition of dTC12 was attributed to the synergistic effect between chloride anion and quaternary ammonium ion. The protective efficiency of the film was higher than 90%, indicating that corrosion of carbon steel in 1 M HCl is reduced by dTC12.The effect of dissolved oxygen on the inhibition efficiency was also investigated. The results show that the inhibition efficiency increases in early stage and decreases for a long immersion time.