碳钢在模拟海水中的腐蚀行为研究

采用静态挂片试验、动电位极化曲线试验研究了碳钢在模拟海水中的腐蚀行为。结果表明,Cl~-对腐蚀的影响最大,且腐蚀速度随着Cl~-浓度的增大先增大后减小,腐蚀形式主要为孔蚀;电极过程表现为阳极的极化率较小,阴极腐蚀过程的速度由氧的扩散过程所控制,腐蚀主要是氧的去极化所致。     

铸造Cu-Al-Be阻尼合金在海水中的腐蚀行为

通过黄海和东海水域 6～ 14个月的全浸挂片试验 ,显示了经过铸态时效的Cu Al Be阻尼合金腐蚀速率为 19 3～2 5 8μm /a ,其腐蚀速度随曝露时间增加而增加 ,具有良好的耐海水腐蚀性能和一定的抗海生物污损能力。结合Neophot 2 1型光学显微镜、JSM 35C扫描电镜、DX -4型特性X射线能谱仪等手段分析讨论了合金的腐蚀特点和机理 ,Cu Al Be合金在海水中基本为单相马氏体组织 ,宏观上表现为均匀腐蚀特征 ,且无缝隙腐蚀迹象 ,但贝类海生物的吸附会造成合金局部表面发生沿晶腐蚀     

Cu-Ni合金海水腐蚀行为研究进展

综述了Cu-Ni合金在海水中材料因素和海水环境及其对腐蚀行为的影响.阐述了该合金海水腐蚀热力学和化学成分、微观组织结构、初始表面状态与耐蚀性的关系;并讨论了海水的物理因素(流速、温度)、化学因素(溶解氧、硫化物)和生物因素及其协同效应对Cu-Ni合金腐蚀过程的影响     

微弧氧化铝合金在海水中的腐蚀行为

采用室内海水浸泡试验、铜离子浸泡试验、电偶试验等方法研究了微弧氧化层和封孔处理对6061铝合金耐海水腐蚀性能的影响。结果显示,微弧氧化后铝合金在海水中的腐蚀形貌为点蚀,封孔处理可明显降低点蚀的发生。与铜合金偶合对微弧氧化铝合金的腐蚀加速较大,在实际使用中应尽量避免两种材料的电接触。     

铸铁在海水中的腐蚀行为

报告了18种铸铁在天然海水和流动海水中的腐蚀试验结果,总结了它们在海水中的腐蚀行为,普通铸铁在天然海水及流动海水中的腐蚀速度与碳钢接近,低合金铸铁在海水中的腐蚀行为与普通铸铁相似。CrSbCu铸铁在海水中的腐蚀比普通铸铁轻,添加Ni,Ni-Cr,Ni-Cr-Mo,Ni－Cr-Cu,Ni-Cr-Re,Cu-Sn-Re,Cu-Cr,Cu-Al等的低合金铸铁在海水中的腐蚀速度与普通铸铁无明显差别,加入少量Ni,Cr,Mo,Cu,Sn,Sb,Re等合金元素可减小铸铁在海洋大气区的腐蚀速度,高镍铸铁在天然海水及流动海水中的腐蚀均较轻。     

镁锂合金在人体模拟汗液中的腐蚀行为

为了研究镁锂合金在人体模拟汗液中的腐蚀特性,测试了镁锂合金在该溶液中开路电极电位与时间的关系曲线及在该溶液中浸泡不同时间的极化曲线,对比了镁锂合金在模拟汗液中及在pH=7的3．5％NaCl溶液中的电化学阻抗谱。采用数码相机、扫描电镜观察了镁锂合金在人体模拟汗液中的腐蚀形貌,用失重法测得了腐蚀速率。结果表明：在1～35min内,随浸泡时间的增加,镁锂合金会出现钝化现象,腐蚀速率降低;镁锂合金在人体模拟汗液中的电化学反应电阻为47．69Ω／cm^2,腐蚀为全面的点腐蚀,腐蚀速率为4．40g／（m^2·h）。     

Ag-Cu-Al-Y合金在Na2S溶液中的腐蚀行为研究

采用腐蚀失重法研究了Ag-Cu-Al-Y合金在Na2S溶液中的腐蚀动力学行为,利用金相(OM)、扫描电子显微镜(SEM)和能谱(EDS)等手段分析了合金腐蚀前后显微组织,探讨了Ag-Cu-Al-Y合金在Na2S溶液中的腐蚀机理。结果表明,添加稀土Y能明显改善Ag-Cu-Al的抗硫化腐蚀性能,其中添加0.03at%Y的银合金具有最小的硫化腐蚀速率。在Ag-Cu-Al-Y合金的硫化腐蚀过程中,腐蚀优先发生在晶界处,腐蚀过程首先形成保护性的致密氧化物层(Y2O3和Al2O3),阻碍氧、硫离子进一步扩散;随着氧化层的逐步剥落,氧、硫离子迅速扩散进入合金内部,并优先与Cu反应形成Cu2S。腐蚀产物内层组织主要为致密氧化物层,外层疏松组织为氧化物和硫化物共存组织。     

超临界水冷壁管材T23在弱碱性S2-溶液中的腐蚀行为

采用挂片试验、电化学工作站、金相显微镜、X射线衍射仪等研究了在不同pH、温度及S2-浓度条件下,T23材料的电化学腐蚀行为及腐蚀产物的特点.根据试验结果分析认为:在温度范围10～70℃条件下,T23的腐蚀程度随着温度的升高加剧,弱碱溶液中S2-对材料表面侵蚀,破坏了OH-的抑制作用;pH=9,t=70℃,0.1 mol...     

Cu-Ti合金的热变形行为及其组织研究

研究了Cu-Ti合金的热模拟压缩试验.试验表明:变形温度的升高和应变速率的减少使峰值应力和稳态应力显著降低,变形温度会影响进入稳态流动所需变形量.建立的Cu-Ti合金高温变形时的流变应力模型表征了变形温度、应变速率和变形程度对流变应力的影响,模型的计算精度较高.根据实验建立了热加工图.通过对热压缩变形过程中组织的观察得出,不连续β相的析出,是材料加工软化的主要原因.     

AZ31B镁合金在模拟流动海水中的腐蚀行为

利用质量损失法及X射线衍射（XRD）、扫描电镜（SEM）测试手段研究了铸态和挤压态AZ31B镁合金在模拟流动海水中浸泡12 h的腐蚀行为及随流速变化的规律。试验结果表明,AZ31B铸态镁合金试样的耐蚀性要远大于挤压态试样,且二者的腐蚀速率随搅拌速度增加的变化趋势有所不同：铸态试样的腐蚀速率随搅拌速度的增加近似呈线性上升,而挤压态试样的腐蚀速率随搅拌速度的增加而先增大后下降。     

Corrosion resistance of steel with hot‐dipped galvanized zinc and zinc alloy coatings in seawater

Hot‐dipped galvanized zinc and zinc alloy coatings were used as protective metallic coatings for steel structures in seawater in China. Corrosion of the two coatings immersed in sea water in Qingdao and Xiamen for 6 years were introduced and analyzed, which provides a basis for further development and applications of these coatings in China. Tests proved that the anti‐corrosion performance of the hot‐dipped low alloy zinc coatings (aluminum content less than or equal to 10 wt%) is equal to or even lower than that of the pure zinc sheet, while the performance of the hot‐dipped high alloy zinc coatings is higher than that of the pure zinc sheet. The hot‐dipped high alloy zinc coatings can be further developed for optimal performance in the future.     

Inconel 625合金在熔融碳酸盐中的腐蚀行为

研究了Inconel625合金在650℃熔融(Li,K)_2CO_3和(Li,K)_2CO_3+Y_2O_3中的腐蚀行为,采用扫描电镜和X射线衍射仪分析了腐蚀产物的形貌和相组成。结果表明,与Inconel625合金在650℃熔融(Li,K)_2CO_3中的腐蚀速率相比,其在650℃熔融(Li,K)_2CO_3+Y_2O_3中的腐蚀速率较小。这是由于Inconel625合金在650℃熔融(Li,K)_2CO_3+Y_2O_3中形成了具有保护性的氧化膜,其组成是NiCr_2O_4、Y_2O_3、NiO、Cr_2O_3。     

Effect of Ti content on corrosion behavior of Cu-Ti alloys in 3.5% NaCl solution

The corrosion behavior of the Cu-Ti alloys with different Ti contents in 3.5% (mass fraction) NaCl solution was investigated using electrochemical measurements, immersion tests, mass loss measurements and SEM observation. The results show that Ti dissolved in the Cu matrix changes the corrosion process of the alloys. Pure Cu sample exhibits a typical active–passive– transpassive corrosion behavior. The anodic polarization current densities of the Cu-Ti alloys steadily increase with increasing applied potential, indicating that active dissolution of copper proceeds due to the potential difference in the galvanic coupling of Cu and Ti. The increase of Ti content decreases the corrosion resistance of the Cu-Ti alloys.     

Effect of CaCl_2 and NaHCO_3 in Physiological Saline Solution on the Corrosion Behavior of an As-Extruded Mg–Zn–Y–Nd alloy

In this study, the corrosion behaviors of an as-extruded Mg–4%Zn–2%Y–1.8%Nd(in wt.%) alloy in different physiological saline solutions were investigated and compared. The results indicated that the alloy in the 9 g/L NaCl had the higher corrosion resistance than that containing with CaCl_2 and NaHCO_3. Moreover, it demonstrated that the corrosion behaviors of the alloy in two types of solutions were all dependent on the pre-immersion time. In the 9 g/L NaCl solution, the corrosion current densities of the alloy decreased firstly with the pre-immersion time being 4 h and then increased with the pre-immersion time prolonging from 4 to 48 h. However, in the 9 g/L NaCl solution containing with CaCl_2 and NaHCO_3, the corrosion current density of the alloy exhibited the adverse trend with the prolonging the pre-immersion time. Failure analysis demonstrated that the changes of corrosion resistance in two solutions were mainly dominated by the constituents formed in surface films.     

Corrosion behavior of laser melted AZ91HP magnesium alloy

AZ91HP magnesium alloy was melted by CO₂ laser. Compared with as‐received Mg alloy, the grain of the melted layer was refined significantly and the content of Al was increased. The corrosion resistance of the melted layer was improved because of the grain refinement, the redistribution of β‐Mg₁₇Al₁₂ and the increasing of the Al content. As compared to the non‐overlapping zone, the overlapping zone of the melted layer was liable to be corroded.     

Cu-Zn-Al形状记忆合金在模拟宫腔液中的腐蚀行为

采用化学失重法、电化学方法和原子吸收光谱法研究了紫铜、Cu-Zn-Al形状记忆合金和Cu-Zn-Al合金在模拟宫腔液中的腐蚀行为.结果表明, 模拟宫腔液中紫铜、Cu-Zn-Al形状记忆合金和Cu-Zn-Al合金的腐蚀历程受阴极氧去极化步骤控制.Cu-Zn-Al形状记忆合金和Cu-Zn-Al合金由于铝的表面离子化倾向比锌的大, 优先形成致密坚固的保护性氧化铝膜, 降低了腐蚀速率.在模拟宫腔液中发现Cu-Zn-Al形状记忆合金和Cu-Zn-Al合金发生脱铝腐蚀, Cl-参与腐蚀反应历程, 促进脱铝腐蚀的进行.白蛋白与氧的竞争吸附加速了阳极溶解, 使紫铜、Cu-Zn-Al形状记忆合金和Cu-Zn-Al合金的阳极活性电流密度随白蛋白浓度的上升而增加.     

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.     

Corrosion behavior of LY12CZ aluminum alloy in simulated acid rain solution

The variations of corrosion potential,electrochemical impedance and surface morphology of LY12 aluminum alloy with pH of simulated acidic rain solutions were investigated with EIS and SEM.It is found that corrosion potential shifts to less noble value with increasing pH in the solutions of pH lower than 3.1 and shifts to more noble value in the solutions of pH higher than 3.1.In the solutions of pH lower than 3.1,the electrochemical impedance diagram has a capacitive loop at higher frequency and an inductive loop at lower frequency and the magnitude of high frequency loop decreases with decreasing pH and increasing period of immersion.However,in the solutions of Ph higher than 3.4 two capacitive loops appear and the magnitude of high frequency loops increases with pH ad period of immersion.Observation of SEM shows that the pitting intensity increases with decreasing pH in the range of pH2.0-3.4,no evident pits are observed at pH higher than 3.4.The experiment results were discussed from resistance of oxide film and adsorption processes of anions in simulated acid rain solution.