醋酸浓度对钛在共沸溶液中的腐蚀行为影响

钛盘的腐蚀是醋酸精馏塔安全稳定生产过程中亟待解决的一个问题,然而,影响钛材腐蚀的因素较多,很多腐蚀规律还不清楚。基于某化工厂钛材醋酸精馏塔的实际腐蚀工况,采用电化学阻抗谱和动电位极化法原位研究了钛材在不同模拟共沸醋酸溶液中的腐蚀行为,用金相显微镜观察了腐蚀前后的形貌变化,对极化曲线和阻抗谱曲线进行了模拟计算得到腐蚀动力学参数,探讨了腐蚀溶液浓度和腐蚀时间对钛板腐蚀行为的影响规律,分析了腐蚀机理,发现醋酸浓度和腐蚀时间对钛板的腐蚀影响较大,高浓度醋酸共沸体系中钛有利于钝化,当醋酸浓度由60％增大至97．5％时,钝化膜阻抗AK486．7Q增大至16000Q,腐蚀速率从5．80×10-10g／（m2-a）降低至5．66×10-11g／（m2．a）,但是腐蚀时间延长会破坏钝化膜,97．5％醋酸的共沸溶液中,当腐蚀时间由30min增大至60min时,钝化膜阻抗从16000Q降低至14600Q,腐蚀速率Ak5．66×10-11g／（m2．a）增大至2．97×10-10g／（m2．a）。实验结果为工业醋酸精馏塔中钛的防护提供了重要参考价值。     

温度对钛-钯合金在甲酸溶液中腐蚀行为的影响

采用电化学法和腐蚀浸泡法,并结合SEM和XRD等分析手段,研究了钛-钯合金在甲酸溶液中的腐蚀行为.结果表明:随着甲酸溶液温度的升高,钛-钯合金的耐蚀性降低,当温度为80℃时,会发生吸氢反应,且可能发生了点蚀;若延长实验时间,提高甲酸溶液的温度或体积分数,会使钛-钯合金腐蚀加重.钛-钯合金设备不适用于高温、高体积分数的甲酸介质中.     

钛及其合金在氯化钠溶液中的腐蚀

分析了不同工况(如浓度、温度、p H值)下,钛及其合金在氯化钠盐水溶液中的腐蚀情况,并给出它们在氯碱工业盐水系统的使用建议。     

氢氧化镁水热反应溶液对钛的腐蚀原因分析

文章简单介绍了卤水溶液合成氢氧化镁时金属的腐蚀机理，并采用电化学测试法研究了工业纯钛的氯化物水溶液中的腐蚀行为。结果表明工业纯钛在氯化物溶液中易发生严重的缝隙腐蚀，但发生点蚀的可能性不大。     

钛的应用开发和腐蚀研究

概述了钛的应用开发现状和各种特殊腐蚀形式,介绍了几种常用的钛材料的防腐蚀措施。     

钛及其合金的氢脆腐蚀

钛是最易吸氢的工业材料,其氢腐蚀主要表现为氢脆。化学工业中使用钛所发生的事故大部分是由钛的吸氢而造成氢脆破裂引起。钛氢脆一直是钛作为结构材料能否获得广泛安全使用的威胁。本文概述了氢在钛中行为和氢脆机理以及影响钛氢脆的各种因素,总结了几种常用的预防措施。     

碳钢在5mmol／L稀NaCl溶液中腐蚀行为研究

采用扫描电镜、Raman光谱、交流阻抗等方法研究了碳钢在5mmol／L NaCl溶液中的腐蚀行为。结果表明,金属表面将形成疏松锈层,其显著影响碳钢腐蚀过程。锈层由薄y-FeOOH层及厚Fe2O4层构成;其中Y—FeOOH易被还原而起氧化剂作用;Fe2O4层起大阴极作用,溶氧可直接在其表面还原。因此,锈层无法阻碍碳钢腐蚀,并且将加速其腐蚀过程;最终碳钢腐蚀速率由溶液中的氧极限扩散速度所决定。防腐措施心能抑制锈层的腐蚀促进作用。     

铝合金在NaCl溶液中小孔腐蚀行为研究

本文通过测定Ａｌ－Ｚｎ－Ｉｎ－Ｓｉ合金在不同浓度ＮａＣｌ溶液中的孔蚀电势Ｅｂ，研究了Ｃｌ￣－浓度和温度变化对铝合金孔蚀性能的影响。结果表明，随Ｃｌ￣－浓度增大和温度升高，合金的孔蚀电势变负，耐孔蚀性能降低。铝合金腐蚀表面电子探针分析结果表明，孔底Ｉｎ元素含量高于合金中的平均含量，孔蚀发生在富Ｉｎ点周围。     

液相还原法制备Co-Fe-Cr合金在NaOH溶液中腐蚀行为研究

采用液相还原法(LPR)通过真空热压技术得到了LPR Co-40Fe-20Cr块体合金,并与粉末冶金法(PM)制备的PMCo-40Fe-20Cr块体合金对比,通过电化学测量系统,研究了两种合金在质量分数为0.1%的NaOH溶液中的腐蚀行为。通过动电位极化曲线和交流阻抗谱分析发现,两种合金都发生了活性溶解,LPR Co-40Fe-20Cr合金的腐蚀电流密度高于PM Co-40Fe-20Cr合金,且PM Co-40Fe-20Cr合金的传递电荷电阻大于LPR Co-40Fe-20Cr合金,即PM Co-40Fe-20Cr合金的耐腐蚀性较好。     

In vitro corrosion behaviour of titanium alloys without vanadium

The corrosion behaviour of three new non-toxic titanium alloys for use as biomaterials has been investigated. The corrosion current densities of these Ti alloys have low values, indicating a passive state that is stable with time. These values were calculated by using both direct and alternate current methods. The comparison with Ti-6Al-4V, widely used as biomaterial, shows slightly lower corrosion rates for the non V-containing alloys. To determine the pitting corrosion resistance, anodic polarisation curves were performed. Those alloys containing Zr, with very low passivation current densities, show the best behaviour. This indicates a low susceptibility to localised corrosion in these alloys. The chemical surface analysis performed on the samples suggests an influence of the passive layer composition on the passivation current density.     

The dissolution of activated titanium slag in dilute sulfuric acid

Finely ground titanium slag (–400 mesh) dissolves slowly in dilute H₂SO₄ (2–10 mol/L) in the temperature range 70–110°C, but attrition ground slag dissolves much faster under similar conditions. The process is strongly dependent on the speed of agitation in the region 345–1035 rpm, and has an activation energy of 28 kJ/mole TiO₂, thus suggesting that the dissolution is controlled by diffusion through the boundary layer.     

The influence of hydrofluoric acid and fluoride ion on the corrosion and passive behaviour of titanium

The title subject has been studied by stationary and transient polarization measurements on titanium electrodes in 1.0 M HCl + x M HF and in 0.1 M NaOH + (0.9−x)M NaAc + x M NaF (x = 0–0.1) and by AES and ESCA measurements on the oxide films formed. It is found that HF strongly stimulates the anodic dissolution of passive titanium as opposed to F⁻ which has no effect on the passive behaviour. Potentiostatic transients accord with the Cabrera-Mott equation and exhibit transient super-polarization. Galvanostatic transients yield capacitance data which give linear C⁻¹/E′ curves with slopes depending on the HF concentration. The surface analytical studies reveal incorporation of fluoride into the oxide film and increased film thickness only at low pH. The AES depth profiles show a smoothly changing fluoride concentration with highest fluoride concentration in the outer part of the passive film (near the oxide—solution interface). Both the AES depth profiles and the capacitance data indicate increased surface roughness of titanium in HF solutions.     

耐稀盐酸泵用材料的研究

本文确定了稀盐酸泵所用材料的化学成分。采用金相显微镜、Ｘ射线衍射和腐蚀试验等方法，研究了新型不锈钢的成分、显微组织与耐蚀性能之间的关系，以及不同的固溶处理温度对耐蚀性能的影响。研究结果表明，该钢经１１５０℃固溶处理，与高合金不锈钢和铸造镍基合金相比，具有较好的耐稀盐酸腐蚀性能。     

Effect of biofouling on corrosion behaviour of grade 2 titanium in Mandapam seawaters

Titanium has the ability to withstand extremely high seawater velocities with negligible corrosion. The inherent passive nature of the metal favours the attachment of bio-organisms more. In this paper the biofouling characteristics and the influence of macrofouling on grade 2 titanium have been investigated in the Palk Bay waters of Mandapam (India) over a period of a year.This work comprises both field exposure as well as laboratory studies. The deposits on titanium were analyzed with the XRD technique. Green algae such as Cladophorapsis zoolengeri, Cheatomorpha area, Chlorodesmis hillibrandii, Enteromorpha intestinalis, Cladophora species and red algae species of Hypnea valentiae, and animals such as bryozoans and barnacles 4 mm in size were identified on the titanium metal surface. The effect of macrofouling on corrosion of titanium was investigated by both impedance and polarization techniques. Titanium experienced negligible corrosion in seawater exposure with an appreciable fouling load of 0.4527 kg.m⁻²y⁻¹.     

气—液式热管换热器在硫酸工业中的应用研究

本文研制的气－液式热管换热器应用于硫酸生产中ＳＯ３气体的余热回收。它具有传热性能好、流动阻力小、寿命长、体积小、节能效果显著和易清垢等优点。     

Electrochemical behaviour and corrosion of lead in some carboxylic acid solutions

The electrochemical behaviour and corrosion of lead in various concentrations of acetic, lactic (0·01 M –1·0 M ), oxalic and tartaric (0·01 M –0·15 M ) acid solutions were studied at 25°C by a potentiodynamic method. The lead anode is readily soluble both in acetic and lactic acid solutions up to 2000 mV. In these two acid solutions, the anodic dissolution of lead increases with increases in the acid concentration and the dissolution process is under charge transfer control. Lactic acid is more corrosive than acetic acid. However, in oxalic and tartaric acid solutions, the E/i profiles depend on the acid concentration. Above a certain specific concentration, the profiles exhibit an anodic current peak associated with a dissolution of the metal and the formation of a passivating lead salt film and a cathodic peak which is related to the reduction of the film. The active dissolution of the lead increases with the acid concentration, the scan rate and stirring of the solution. The passivation of lead in these two acid solutions occurs by a dissolution–precipitation mechanism and the process is controlled by diffusion. X-ray diffraction analysis confirmed the presence of a passivating salt film (either lead oxalate or lead tartrate) on the electrode surface. © 1998 SCI     

Anodic behaviour of titanium in concentrated sulphuric acid solutions. Influence of some oxidizing inhibitors

The anodic polarisation behaviour of the titanium electrode and the rate of corrosion are measured in aqueous sulphuric acid solutions as a function of the electrolyte concentration. Increasing acid concentration increases the critical current for passivity. This current passes through a maximum (4.88 mA cm^–2) at 25 N and then decreases again. Increasing temperature increases the critical current for passivity. The effect of oxidizing agents such as K₂Cr₂O₇, KMnO₄, KIO₃, Na₂MoO₄, NaClO₃, HNO₃ and TiCl₄ on the polarisation of titanium are also investigated. K₂Cr₂O₇, HNO₃, TiCl₄ are the most powerful corrosion inhibitors at room temperature and also at 80° C in 10 N H₂SO₄, while in more concentrated sulphuric acid solution (25 N), corrosion inhibition is observed only by HNO₃ for a very short period.     

酸洗过程中的缓蚀剂

通过对近十年来酸洗缓蚀剂的研究工作的介绍与分析,结合清洁生产的要求及定量化计算数据,明确指出酸洗缓蚀剂在酸洗废液减量化的意义,并对进一步研究与开发绿色酸洗缓蚀剂提出值得重视的几个问题。