镁合金具有良好的生物相容性及可降解性能,因而有潜力应用于生物医用领域.最近几年,生物医用镁合金的研究得到了广泛的重视.镁合金用于生物医用植入材料的主要问题是耐蚀性差,提高耐蚀性能的方法主要有调整合金成分和采用适当的表面处理技术.本文对镁合金作为生物医用材料的腐蚀机理和影响腐蚀的因素进行了介绍,并总结了最近几年在提高生物医用镁合金耐蚀性能方面取得的进展,最后对生物医用镁合金研究中需要解决的问题和研究趋势进行了分析.
Magnesium alloys are potential biodegradable materials for their outstanding biological performance. More attention has been paid on biodegradable magnesium alloys in recent years. However, the degradation of magnesium alloys is too fast in human body fluid or blood plasma. Ways to improve their corrosion resistance include modification of alloy compositions and proper surface treatment. This paper discusses the corrosion mechanism of magnesium alloys as biomaterials and the influencing factors. Also, progresses achieved in improvement of the corrosion resistance in recent years are reviewed. Finally the problems and trends for their application as biomaterials are proposed.
介绍了国内外在纳米金属的耐腐蚀性能方面的研究现状, 讨论了纳米化对金属耐腐蚀性能的不同影响, 分析了影响纳米金属腐蚀行为的因素, 并对纳米金属产生不同耐腐蚀性能的原因进行了总结.
Progress at home and abroad of corrosion research for nanocrystallized metals is introduced in this paper. Different effects on corrosion performance of nanocrystallized metals are discussed. The influencing factors on corrosion behavior of nanocrystallized metals are analysed. The reasons for different corrosion performance of nanocrystallized metals are summarized.
海洋污损生物对船舶等海洋结构物的污损已经成为人类从事海洋开发活动的一大障碍. 本文综述了污损生物附着机理及其危害, 介绍了当前工程应用和研究中的主要防污损技术: 物理防污法、化学防污法和生物防污法. 分析了各类防污方法的防污机理及优缺点, 展望了防污技术未来的研究和发展趋势.
The fouling organism accreted to marine installations is a major factor affecting their safety and service life. The tarnish of marine fouling organism to marine structures such as ships has become tremendous impediment to human activity in ocean. This article summarizes the adhesion mechanism and scathes of marine organism. Besides, the main antifouling methods at present, which classified as physical method, chemical method and biological method, are analyzed in term of antifouling mechanism, relative merits and so on. Finally, the future trends of antifouling methods research and development have been suggested.
压水堆核电站运行过程中, 蒸汽发生器二次侧流动受限区域的表面污垢及缝隙中的有害杂质离子(如Cl－, SO42－, Ca2+, Mg2+, Al3+等)因水的蒸发会出现局部浓缩. 通过监测机组停运期间的水化学可以推断机组正常运行期间蒸汽发生器二次侧的杂质浓缩情况. 本文分析和评估了某核电站降功率、降温期间蒸汽发生器的3次杂质隐藏返回试验数据. 结果表明, 隐藏区内的Al3+浓度逐年增加; 根据隐藏返回数据得到的高温pH 值(pHT)在正常的耐腐蚀pH值范围内; 建议机组降温的时间应该进一步延长, 以便杂质离子尤其是阴离子完全返回进入大空间溶液并通过排污水系统排出.
During ordinary operation of a pressurized water reactor (PWR) of nuclear power plant (NPP), some deleterious ionic impurities such as Cl－, SO42－, Ca2+, Mg2+, Al3+ etc. hidden in fouling and crevices for secondary side of steam generator (SG) would concentrate especially in flow-restricted regions. Concentrating situation of the deleterious impurities could be evaluated through secondary water chemistry measurement. In this paper, evaluation and analysis were made from three sets of practical hideout return (HOR) testing data for a NPP. The results indicated that pHT in crevice was in ordinary range from viewpoint of corrosion resistance according to HOR data. However, the concentration of Al3+ increased year by year and the reasons need to be further investigated. It is suggested that the time of hideout return tests during steady state should be extended so that the impurities could be completely returned.
在镀锌钢板表面制备了丙烯酸树脂复合膜, 用扫描电子显微镜观察膜层的微观形貌. 用傅里叶变换红外光谱表征膜层的分子结构, 用中性盐雾试验和电化学方法测试其耐蚀性, 并用划痕浸泡实验测试膜层的自修复性能. 结果表明: 丙烯酸树脂复合膜表面致密平整; 耐中性盐雾腐蚀达72 h; 阻抗值和极化电阻值均较大,说明丙烯酸树脂复合膜能有效抑制腐蚀电化学反应; 划痕浸泡试验证明丙烯酸树脂复合膜具有自修复功能.成膜过程中碳酸锆铵能够和丙烯酸树脂分子上的羟基和羧基发生交联反应, 形成互穿网络结构, 提高膜层内部的交联密度, 有效地阻挡外界环境的侵蚀, 当膜层破损时钼酸盐和磷酸盐与锌反应形成难溶盐吸附在破损处, 起到自修复作用.
A complex acrylate resin coating was synthesised on galvanized steel sheet. The micro-morphology of the coating was observed by SEM. FTIR spectra was used to characterize the molecular structure of the complex acrylate resin coating. The corrosion resistance of the coating was evaluated by neutral salt spray test and electrochemistry test. The self-rehealing performance of the coating was examined with immersion scratch test. The results show that the surface of the coating was uniform and compact. The coating could endure neutral salt spray test for 72 h. And therewith increase the corrosion resistance of galvanized steel sheet with higher impedance and polarization resistance in comparison to the bare galvanized steel sheet. The immersion scratch experiment confirmed that the coating exhibited self-rehealing performance to some extence. The crosslinking reactions may be taken place between ammonium zirconium carbonate(AZC) and hydroxyl and carboxyl of the acrylic resin during synthesis so that to form a high crosslinked density interpenetrating structure network so that the coating could become much effective as a barrier for corrosive substances. When the coating was damaged, there was reaction might take place between zinc with molybdate and phosphate on the surface of zinc to produce water-insoluble salts, which could absorb on the surface of zinc spontaneously to play an important role in coating rehealing.
采用电化学测试和慢应变速率拉伸(SSRT)方法, 结合扫描电镜(SEM)评价321 不锈钢在淡化海水中的耐蚀性. 循环伏安实验表明, 随着温度的升高, 点蚀击破电位负移, 耐点蚀性能下降;321 不锈钢在淡化海水中的临界点蚀温度(CPT)为30.5 ℃. SSRT 实验结果表明, 321 不锈钢在淡化海水中具有一定的应力腐蚀开裂(SCC)敏感性, 随着温度的升高, 应力腐蚀敏感性增大. 在35 ℃和50 ℃, 321 不锈钢在淡化海水中的断裂为韧性断裂;而在70 ℃, 断口微观形貌呈现韧窝+少量准解理形貌, SCC敏感性增强.
Electrochemical measurement, slow strain rate test and SEM observation of fracture surfaces were used to study the corrosion behavior of 321 stainless steel in desalinated seawater. The result of cyclic voltammetry indicates that the pitting potential goes negative with the temperature rising, and thereby the pitting corrosion resistance decreases. Critical pitting temperature (CPT) of 321 stainless steel is 30.5 ℃ in desalinated seawater. SSRT results show that 321 stainless steel is relatively sensitive in desalinated seawater. At 35 ℃ and 50 ℃, 321 stainless steel shows ductile fracture, however the fractured surfaces exhibit ductile plus quasi-cleavage fracture at 70 ℃, and the sensitivity of SCC is inceraesed.
利用Tafel曲线、阻抗谱分析、NaCl水溶液点滴实验和扫描电镜观察等手段, 研究了温度对AZ91D镁合金的植酸转化膜表面形貌及耐蚀性的影响. 结果表明: 当温度为25 ℃ ～35 ℃时转化膜的耐蚀性较好, 温度过高或过低都会使转化膜的耐蚀性变差; 转化膜表面的裂纹是在干燥处理过程中由于表层转化膜体积收缩而产生的; 镁合金表面形成的植酸转化膜应属于电子导体, 该层膜的形成阻碍了腐蚀介质与镁合金基体的接触, 同时抑制腐蚀产物的扩散, 对镁合金起到了较好的防护作用.
AZ91D magnesium alloy, was treated in solutions of phytic acid at different temperature. SEM, Tafel and EIS were adopted and spot test was carried out to investigate the influence of processing temperature on appearance and corrosion resistance of conversion coating. Results show that the phytic acid conversion coating have better corrosion resistance when magnesium alloy was treated in a temperature range between 20 ℃ and 35 ℃. The corrosion resistance would become poor of the coatings prepared at temperature beyong the above range. The appearance of cracks on the conversion coating surface may be resulted from dehydrating in the process of desiccation. The conversion coating is a kind of coating that hinders the contact between corrosion medium and matrix metal and inhibits the diffusion of corrosion products.
用水泥提取液模拟混凝土孔隙液, 用自腐蚀电位、动电位极化和电化学阻抗技术, 研究单掺粉煤灰或矿粉、复掺粉煤灰和矿粉对混凝土中钢筋氯盐腐蚀行为的影响. 结果表明, 粉煤灰和矿粉均能有效降低钢筋受氯离子腐蚀的风险, 减小腐蚀速率, 并能不同程度地提高钢筋腐蚀的临界氯离子浓度. 抑制氯离子腐蚀能力由强到弱依次为:矿粉＞矿粉+粉煤灰＞粉煤灰＞水泥. 且随氯离子浓度的增大, 矿粉和粉煤灰的阻锈效率会有不同程度的下降. 用矿粉和粉煤灰按适当比例复掺的方法来对抗氯离子腐蚀不仅经济, 而且有不错的阻锈效果.
By means of free corrosion potential measurement, potentiodynamic and electrochemical impedance spectroscopy etc, the effect of fly ash and slag on corrosion behavior of reinforcing rebar was investigated in solution of cement extract with contaminant of chlorides, which was adopted to simulate the known concrete pore solution in reinforcements. The results show that fly ash and slag can effectively reduce the risk of chloride induced corrosion and the corrosion rate of reinforcing steel rebar. Besides, the threshold value of chloride for corrosion is increased to some extence. The inhibition ability to chloride induced corrosion is in the order of: slag > slag + fly ash > fly ash > cement. In addition, the corrosion inhibition efficiency of slag and fly ash decreases to some extent with the increase of the chloride concentration. The admixture of fly ash and slag at a appropriate proportion is excellent corrosion inhibitor for chloride induced corrosion to steel rebar in terms of cost and effectiveness.
用稳态极化曲线和电化学阻抗谱方法研究了镀锡板、彩印铁和实罐的腐蚀电化学行为特征. 结果表明, 未经钝化处理的镀锡板腐蚀电流密度接近40 μA/cm2, 而钝化处理后的镀锡板腐蚀电流密度降低至原来的1/10, 耐蚀性显著提高. 电化学阻抗测试结果表明, 与彩印铁相比实罐阻抗模值下降近3 个数量级, 说明经过一系列制罐加工工艺后涂层的耐蚀性显著下降. 因此, 镀锡板进行钝化处理以及对罐底收缩部位进行涂层修复、或采用更耐加工型的涂料能够有效提高金属饮料罐的货架寿命.
Metal packaging is an industry sector of rapid development. However, the corrosion of metal cans caused by packaged corrosive drinks may shorten the service life of the cans. It was frequently seen that there were large area with corroded spots even perforations on the shrinkage area of the cans. To find out the causes of corrosion of metal cans and increase its corrosion resistance, a study on corrosion behavior of tinplates, color printing iron and filled cans was made in this paper using steady-state polarization curves and electrochemical impedance spectroscopy. The results indicated that the corrosion current density of the bare tinplate reach 40 μA/cm2, on the contrast, the corrosion current density of the passivated tinplate dropped nearly 10 times. The impedance measurement showed the same results. Electrochemical impedance test of real cans and color printing iron showed that the impedance values of filled cans dropped nearly 1000 times, compared to that of color printing iron, which revealed that after a series of can-making processes the performance of coating was detriorated significantly. It is suggested that the following measures may be the useful for improving the service life of metal cans: the passivation of tinplates or remedy of shrinkage parts of cans after making processes or application of coatings with performance much compatible to the making processes.
通过动电位扫描测试、XRD分析、SEM观察, 研究了镍基合金Incoloy800 和Incoloy840 镍基合金加热管试样经过HNO3钝化、涂覆SiO2膜两种表面处理后抗腐蚀性能的变化. 结果表明: 钝化处理显著提高Incoloy840镍基合金的点蚀电位和保护电位, 而对Incoloy800 镍基合金的保护电位影响较小, 几乎没有改变其点蚀电位;以正硅酸乙酯作为前驱体, 两种PEG 表面活性剂作为模板剂, 在静电和氢键驱动力的共同作用下组装生成SiO2溶胶, 涂覆在镍基合金加热管表面形成的膜层均匀致密、性能良好; 涂覆SiO2膜层显著提高了两种镍基合金加热管的自腐蚀电位和点蚀电位. 上述表面处理工艺均提高了两种镍基合金加热管的抗腐蚀性能.
Corrosion performance of Ni-base alloys Incoloy800 and Incoloy840 after HNO3 passivation treatment or application of SiO2 coating was studied by potentiodynamic polarization test, XRD and SEM. The result showed that after HNO3 passivation treatment the pitting potential and protection potential of Incoloy840 increased significantly, while Incoloy800 showed a few change in protection potential and little change in pitting potential. Flaw-less SiO2 coating can be applied on the two alloys with TEOS and two surfactants (PEG200, PEG20000). The open-circuit potential and pitting potential of the two Ni-based alloys increased significantly after application of SiO2 coating. Therefore, the corrosion resistance of the two Ni-based alloys may be significantly enhanced after surface treatments above.
利用电化学阻抗谱技术, 研究X70 钢的最佳阴极保护电位随土壤中Cl－和含水率的变化. 结果表明:在Cl－含量< 10 mmol/kg 时最佳保护电位随着含水率的增加先升高后降低, 变化幅度在150 mV左右; Cl－含量≥10 mmol/kg 时, 最佳保护电位随着含水率增加呈现降低的趋势; Cl－含量为20 mmol/kg 时的不同含水率的土壤中最佳保护电位均达到最小值; 随着含水率的升高Cl－对最佳保护电位的影响逐渐减小.
The relationship of moisture and chloride ion content in Qingdao soil with the optimum cathodic protection potential for X70 steel was studied by electrochemical impedance spectroscopy(EIS)in a laboratory test set. The results revealed that the optimum cathodic protection potential increased firstly, then reduced with the increase of moisture content when chloride ion was less than 10 mmol/kg with a potential fluctuation about 150 mV. When the chloride ion is greater than 10 mmol/kg, the optimal protection potential showed a trend of reducing with increasing moisture content. The optimal cathodic protection potential in soil with various moisture contents reached a minimum for chloride ion content of 20 mmol/kg. With the rise of moisture content, the influence of chloride ion decreased gradually.
阿尔及利亚某炼化工程一台凝析油/重柴油换热器抽芯检查过程中发现换热管束有明显冲刷腐蚀. 发生腐蚀的部位正对重柴油入口, 该处管束顶部有密集分布的冲蚀坑及麻点, 底部蚀坑表面有油污及腐蚀产物附着. 通过金相和扫描电镜观察、能谱分析及双环电化学动电位再活化等多种方法分析了冲刷腐蚀的成因和热处理对TP405管束材料耐晶间腐蚀性能的影响, 对换热器壳程入口冲刷腐蚀预防措施和整改方案提出建议.
After a rutine inspection for a failured condensate/heavy diesel oil heat exchanger in a refinery in Algeria, it followed that the tube bundle of that set was suffered from serious erosion corrosion. The erosion occurred at the location opposite to the heavy diesel oil inlet. On the top surface of the tubes corrosion spots were observed, while corrosion products attached on the bottom surface of these tubes. Metallography, scanning electron microscope (SEM), energy dispersive spectrum (EDS) and electrochemistry tests were conducted to investigate the reason of this erosion corrosion, as well as the effect of heat treatment on the erosion resistance of TP405 tube bundle. Then solutions for this corrosion were proposed to avoid such kind of damage in the future.
某核电站在运行8 年以后, 高压加热器水室隔板发生腐蚀穿孔. 本文从失效有关的因素如水室结构、水室用材料和水化学等入手, 分析了发生穿孔的原因, 同时采用有限元方法分析流体相关因素, 得出发生失效的原因是流动加速腐蚀.
After 8 years operation, a clapboard in water box of high pressure heater experienced perforation corrosion in a nuclear power plant. The structure, water chemistry and material of the water box are analyzed so that to trace out the mechanism of corrosion failure. In the meanwhile, the finite element method is used to ascertain the factors influencing corrosion failure. At last, the reason for failure is given, which is flow accelerated corrosion.
