材料腐蚀与装备环境工程

提出要重视自然环境对装备的影响．论述了材料环境适应性是装备环境工程的重要基础．列举了我国不同自然环境对不同材料服役性能的影响,介绍了我国材料自然环境腐蚀试验研究工作的重要进展,强调了当前要特别加强装备环境工程薄弱环节的工作。     

高温高湿高盐环境雷达典型部件腐蚀分析

目的研究雷达典型部件长期工作在高温、高湿、高盐雾等环境下腐蚀情况的影响机理。方法提出在该环境下对雷达典型部件多场耦合的仿真计算方法,以计算流体动力学(CFD)软件FLUENT为平台,建立雷达典型部件的有限元模型,对雷达典型部件进行仿真模拟分析。结果得到了雷达典型部件的温度、湿度和盐度分布云图和综合环境腐蚀云图,从腐蚀云图可以看出,部件表面腐蚀程度在0.6 mm以上,腐蚀程度比较严重,仿真结果与实际检测结果较为吻合。从分布云图可知,单一的温度或盐度因素对部件表面的腐蚀情况影响较小,湿度对其影响较为显著。结论验证了仿真计算方法的合理性和正确性,为雷达典型部件的动力学仿真,为其腐蚀现象的进一步研究及预防提供了理论指导。     

5083铝合金在淡海水交替自然环境中的腐蚀行为研究

目的研究5083铝合金在淡海水交替自然环境下的耐蚀性能。方法参照GB/T 5776,分别在淡海水交替、海水及淡水自然环境中开展5083铝合金2年的耐浸泡试验。采集每周期试验样品的腐蚀数据,并进行5083铝在三种自然水环境下的耐蚀性能比对。采用腐蚀电位、交流阻抗等电化学方法,对其耐蚀性能进行评价。结果 5083铝在淡海水交替自然环境下腐蚀严重,腐蚀速率是海水环境下的5.3倍,是淡水环境下的15.8倍。点蚀密度最大,平均点蚀深度是海水环境下的2.6倍,是淡水环境下的1.7倍。结论 5083铝在淡海水交替自然环境下的耐蚀性差,并从电化学试验结果上得到很好的验证。     

Cr元素对铁合金抗热强碱磨损腐蚀性能的影响

测定了10钢、20Cr5、20Cr11含铬铸钢和185Cr13、295Cr26高铬铸铁在85℃的质量浓度为303g蛐L的NaOH溶液中的腐蚀速率、电位鄄时间曲线、静态及冲刷条件下的电化学曲线。实验结果显示,铬钢和铬铸铁在静态浸泡中,电位都经历过高—低—高的变化,表明其腐蚀历程相似。在静态条件下,含铬量高的铬钢和铸铁腐蚀失重大于含铬量低的材料。在冲刷条件下,由失重法获得的总失重和由极化曲线计算得到的腐蚀失重均显示含铬高的铸铁抗磨损腐蚀性能优于含铬量相对低的铸铁。增加铬含量,对合金抗热强碱的纯腐蚀有不利的影响,但却有利于材料抗热强碱介质的磨损腐蚀。     

不锈钢深海腐蚀研究

综述了不锈钢在深海条件下的点蚀、缝隙腐蚀、隧道腐蚀、应力腐蚀机理和影响因素及相应的腐蚀防护方法。用不锈钢在深海中发生腐蚀的实例说明了国内不锈钢深海应用存在的问题以及与国外深海腐蚀研究之间存在的差距。     

船体钢室内加速腐蚀和海水腐蚀的相关性研究

通过在天然海水中添加H2O2进行室内模拟加速试验。通过失重分析、腐蚀形貌分析和产物组成分析研究了船体钢海水腐蚀模拟试验和自然腐蚀试验的相关性。利用Spearman秩相关系数法得到了相关系数。结果表明,在室内模拟加速试验与自然环境试验中,船体钢的腐蚀规律均符合幂函数模型,Spearman秩相关系数较高,两种试验方法具有较好的相关性。     

某型飞机腐蚀关键结构含涂层模拟件腐蚀行为研究

目的研究某型飞机腐蚀关键结构防护涂层体系的腐蚀失效行为,评估涂层的防护性能,为整机日历寿命体系评定和飞机大修提供试验依据。方法在编制加速环境谱的基础上,对模拟件进行环境谱作用下的加速腐蚀试验。结果在经过修理前后两个阶段的加速腐蚀后,模拟件在铆钉连接区域表面涂层均出现不同程度的鼓包、开裂、剥落等老化现象。结论腐蚀关键结构表面防护涂层体系总体上能够满足首翻期和翻修间隔期内结构的表面防腐要求,但在外场使用维护中应针对铆钉、螺钉连接件周围等腐蚀敏感部位加强防护,一旦出现涂层老化、破损等损伤需要及时进行局部修复。在科学、合理的外场使用维护条件下,可以适当延长飞机的进厂大修时间。     

Synergistic effects of sodium hypochlorite disinfection and iron-oxidizing bacteria on early corrosion in cast iron pipes

• The early corrosion process in the cast iron pipes was investigated. • The increase of NaOCl (<0.75 mg/L) accelerated the cast iron corrosion. • Biocorrosion caused by IOB could be divided into three stages in the early stage. • Synergistic and antagonistic effects exist between residual chlorine and IOB. Corrosion in drinking water distribution systems (DWDSs) may lead to pipe failures and water quality deterioration; biocorrosion is the most common type. Chlorine disinfectants are widely used in DWDSs to inhibit microorganism growth, but these also promote electrochemical corrosion to a certain extent. This study explored the independent and synergistic effects of chlorine and microorganisms on pipeline corrosion. Sodium hypochlorite (NaOCl) at different concentrations (0, 0.25, 0.50, and 0.75 mg/L) and iron-oxidizing bacteria (IOB) were added to the reaction system, and a biofilm annular reactor (BAR) was employed to simulate operational water supply pipes and explain the composite effects. The degree of corrosion became severe with increasing NaOCl dosage. IOB accelerated the corrosion rate at an early stage, after which the reaction system gradually stabilized. When NaOCl and IOB existed together in the BAR, both synergistic and antagonistic effects occurred during the corrosion process. The AOC content increased due to the addition of NaOCl, which is conducive to bacterial regrowth. However, biofilm on cast iron coupons was greatly influenced by the disinfectant, leading to a decrease in microbial biomass over time. More research is needed to provide guidelines for pipeline corrosion control.     

Runoff rates,chemical speciation and bioavailability of copper released from naturally patinated copper

The release of copper, induced by atmospheric corrosion, from naturally patinated copper of varying age (0 and 30 years) has been investigated together with its potential ecotoxic effect. Results were generated in an interdisciplinary research effort in which corrosion science and ecotoxicology aspects were combined. The aim of the investigation was to elucidate the situation when copper-containing rainwater leaves a roof in terms of runoff rate, chemical speciation, bioavailability and ecotoxicity effects. Data have been collected during a three-year field exposure conducted in the urban environment of Stockholm, Sweden. The potential environmental effects have been evaluated using a combination of a copper specific biosensor test with the bacterium Alcaligenes eutrophus and the conventional 72-h growth inhibition test with the green alga Raphidocelis subcapitata. The results show annual runoff rates between 1.0 and 1.5 g/m2 year for naturally patinated copper of varying age. The runoff rate increased slightly with patina age, which mainly is attributed to the enhanced first flush effect observed on thicker patina layers. The total copper concentration in investigated runoff samplings ranged from 0.9 to 9.7 mg/l. Both computer modeling and experimental studies revealed that the majority (60-100%) of released copper was present as the free hydrated cupric ion, Cu(H2O)6(2+), the most bioavailable copper species. However, other copper species in the runoff water, such as, e.g. Cu(OH)+ and Cu2(OH)2(2+), were also bioavailable. The copper-containing runoff water, sampled directly after release from the roof, caused significant reduction in growth rate of the green alga. It should be emphasized that the results describe the runoff situation immediately after release from the copper roof and not the real environmental ecotoxicity. Therefore the data should only be used as an initial assessment of the potential environmental effect of copper runoff from building applications. Future risk assessments should also consider dilution effects of copper, changes in its chemical speciation and bioavailability during environmental entry, and type and sensitivity of the receiving ecosystem.     

基于腐蚀与盐堵塞问题的超临界水氧化研究进展

超临界水氧化(简称SCWO)以其特有的优点成为了引人注目的有机废水处理方法.在操作过程中,有机物与氧化剂呈现为快速的均相反应,在数分钟内便可完全氧化生成CO2和H20.尽管已建造了工业规模的SCWO装置并用于处理化学废水,但该技术所存在的设备腐蚀以及设备因盐沉积而堵塞的问题制约着该技术的推广应用.为解决上述问题,科技工作者对SCWO工艺进行了改进,并提出了多种新颖的SCWO反应器设计思想.综述了基于解决设备腐蚀与盐堵塞问题的SCWO研究进展,并对相关问题进行了讨论.