铝合金阳极氧化膜醋酸镍封闭方法耐蚀性研究

研究了醋酸镍封闭方法对不同铝合金阳极氧化膜在NaCl溶液中电化学行为的影响,并与沸水封闭方法和重铬酸钾封闭方法作了比较。利用扫描电子显微镜(SEM)观察了封闭后阳极氧化膜的表面形貌。利用能量散射谱(EDS)分析了封闭后阳极氧化膜表面和截面成分。利用动电位极化和电化学阻抗谱(EIS)研究了封闭后阳极氧化膜的腐蚀行为。结果表明:醋酸镍封闭方法可以使铝合金阳极氧化膜具有平整均匀的表面形貌,镍元素分布于整个阳极氧化膜层中。在酸性和碱性溶液中,醋酸镍封闭的铝合金阳极氧化膜比沸水封闭和重铬酸钾封闭的铝合金阳极氧化膜具有更高的耐蚀性,是一种较好的封闭方法。     

铝阳极氧化膜绿色封闭工艺

探索了新的不含有害物质的铝合金阳极氧化膜绿色封闭技术;新方法使用了铈盐化学处理和钼盐溶液电化学处理相结合的工艺。对比了不同封闭方法对L3铝合金阳极氧化膜在NaCl溶液中耐蚀性的影响,包括氟化镍封闭,重铬酸钾封闭和铈-钼盐封闭。利用动电位极化法研究了封闭后阳极氧化膜的腐蚀行为。利用扫描电子显微镜(SEM)观察了封闭后阳极氧化膜的表面形貌和成分。结果表明铈-钼盐封闭工艺可以为铝合金阳极氧化膜在NaCl溶液中提供较高的耐蚀性。     

三种无铬封闭方法对铝合金阳极氧化膜耐蚀性的影响

研究了沸水封闭、醋酸镍封闭和电压加载下己二酸铵封闭对LY12铝合金阳极氧化膜耐蚀性的影响。通过场发射扫描电镜（FE-SEM）和电化学阻抗谱（EIS）对三种无铬封闭方法处理后铝合金阳极氧化膜的表面微观形貌和耐蚀性进行了研究。结果表明：封闭处理可以有效地闭合阳极氧化膜的微孔,提高氧化膜耐腐蚀性能。电压加载下己二酸铵封闭可以有效缓解氧化膜的腐蚀。三种无铬封闭方法处理后的氧化膜耐腐蚀性能从小到大依次为：沸水封闭,醋酸镍封闭,电压加载下己二酸铵封闭。     

铈盐在电场作用下对LY12铝合金阳极氧化膜的封闭作用

研究了铈盐溶液在脉冲电场作用下对LY12铝合金阳极氧化膜的封闭作用.利用扫描电子显微镜(SEM)观察了封闭后阳极氧化膜的表面微观形貌,利用动电位极化技术和电化学交流阻抗谱(EIS)研究了经铈盐封闭后的LY12铝合金阳极氧化膜在不同pH值的1 mol/LNaCl溶液中的耐蚀性,并与重铬酸钾封闭、沸水封闭进行了对比.结果表明,采用该封闭工艺得到的铝合金阳极氧化膜表面平整均匀,在耐蚀性方面优于传统封闭方法,并且降低了成本和减少了能量消耗,对环境无污染,是一种新型的绿色封闭方法,有望替代重铬酸钾封闭法.     

几种封闭方法处理后铝阳极氧化膜的耐蚀性比较

通过极化曲线、开路电位监测、交流阻抗技术等电化学方法研究了工业纯铝L3阳极氧化膜试样在1mol/LNaCl溶液中的电化学行为,比较了经过沸水封闭、重铬酸钾封闭和镍盐冷封闭处理后的氧化膜试样的耐蚀性。结果表明:封闭处理改善了氧化膜试样在氯化钠溶液中的耐蚀性,耐蚀性从弱到强的顺序是:未封闭<沸水封闭<重铬酸钾封闭相似文献   

不同方法评价几种工艺封闭的铝合金阳极氧化膜的耐蚀性

使用磷-铬酸失重试验、铜加速醋酸盐雾试验和电化学技术研究了铈盐封闭的铝合金阳极氧化膜的耐蚀性,并与氟化镍封闭、沸水封闭和重铬酸钾封闭方法进行了对比。铈盐封闭的铝合金阳极氧化膜在磷-铬酸失重试验中失重小于30 mg/dm2,达到了GB/T5237.2-2000中的规定。铜加速醋酸盐雾试验和电化学试验表明,铈盐封闭的铝合金阳极氧化膜的耐蚀性与其它几种方法封闭的铝合金阳极氧化膜的耐蚀性相当。磷-铬酸失重试验、铜加速醋酸盐雾试验和电化学技术这几种方法都可以用来评价铝阳极氧化膜的耐蚀性,且评价结果基本一致。稀土封闭绿色环保,封闭效果好,应用前景良好。     

三价铬和锆盐对铝阳极氧化膜的协同封闭作用

开发了以氟锆酸钾、碱式硫酸铬为主盐的新型无镍常温封闭剂。研究了K_2ZrF_6、Cr(OH)SO_4、添加剂M、添加剂N加入量和封闭时间对铝合金阳极氧化膜耐蚀性的影响规律。结果表明:三价铬和锆盐对铝阳极氧化膜的协同封闭提高了阳极氧化膜的耐蚀性,与传统沸水和镍盐封闭处理相比,采用此方法封闭处理的阳极氧化膜具有更好耐蚀性。     

高耐蚀性铬酸阳极氧化工艺研究

通过厚度、附着力、耐蚀性测试等研究了航空用铝合金的铬酸阳极氧化工艺.结果表明,不同铝合金成分对铬酸阳极氧化膜厚度影响很大,但各种合金的氧化膜厚均大于2 μm;2024-T3铝合金生成的铬酸阳极氧化膜层经重铬酸钾封闭处理可通过750 h的盐雾试验,且未封闭的氧化膜层与涂层具有优异的附着力;铬酸阳极氧化槽液中Cr3+的浓度...     

常温镍盐封闭处理对铝阳极氧化膜性能的影响

为进一步提高铝合金阳极氧化膜的性能,采用以镍盐为主的常温封闭剂对其进行封闭处理。与沸水封闭相比较,分别采用滴碱实验和落砂实验研究了氧化膜封闭前后的耐蚀性能和耐磨性能,结果表明：镍盐封闭处理具有能耗低、污染小、封闭快速等优点,而且耐蚀性和耐磨性明显由于传统的沸水封闭处理,是一种较为理想的封闭处理工艺。     

铈盐封孔对6061铝合金阳极氧化膜耐蚀性的影响

为提高6061铝合金阳极氧化膜的耐蚀性,利用铈盐溶液对其进行封孔处理。用电化学阻抗谱(EIS)和浸泡试验研究了不同工艺铈盐封孔后的氧化膜在质量分数3.5%NaCl溶液中的耐蚀性。同时,通过剥蚀试验对比研究了铈盐封孔与铝溶胶封孔和沸水封孔的效果。结果表明:氧化膜在30℃下铈盐封孔150min可获得较好的耐蚀性;铈盐封孔氧化膜的耐蚀性略低于沸水封孔氧化膜的,但优于溶胶封孔氧化膜的。     

磷酸盐封孔处理对铝合金阳极氧化膜耐蚀性能的影响

为进一步提高铝合金阳极氧化膜的耐蚀性能,采用磷酸盐对其进行封孔处理.利用电化学阻抗谱 (EIS ) 分析该封孔处理对阳极氧化膜耐蚀性能的影响规律,并与常规沸水封孔和铈盐封孔进行比较.实验结果表明,磷酸盐封孔处理后可在阳极氧化膜表面形成约为15 μm厚的致密磷酸盐涂层,与常规沸水和铈盐封孔处理相比,磷酸盐封孔处理的阳极氧化膜具有更好耐蚀性和时效性.该方法可为阳极氧化膜封孔处理提供一种新途径.     

Evaluation of different sealing methods for anodized aluminum‐silicon carbide (Al/SiC) composites using EIS and SEM techniques

Electrochemical impedance spectroscopy (EIS) and the scanning electron microscope (SEM) have been used in an investigation of the effectiveness of various sealing methods that can be used to improve the corrosion resistance of an anodized aluminum‐silicon carbide (Al/SiC) composite. Anodic oxide films were grown on Al7075‐T6 and the Al/SiC composite by sulfuric acid anodizing and sealing in a cold saturated solution of nickel acetate. Other samples were sealed using the traditional method of boiling water or hot nickel acetate for comparison. The results revealed a uniform anodized layer on Al7075‐T6 that resisted pitting corrosion for more than 2 weeks exposure to NaCl, whereas a cracked oxide film with variations in thickness was observed on the composite material. Pit initiation occurred in less than 5 days on the anodized Al/SiC that was sealed in the hot solutions. This study suggests that the traditional hot sealing methods did not provide sufficient corrosion protection for aluminum metal–matrix composites (MMCs) because the reinforcing SiC particles deteriorated the surface film structure. However, this defective film can be repaired by nickel hydrate precipitation during cold sealing or by applying a thick polyurethane coating.     

The effects of sealing on cracking tendency of anodic films on 2024 aluminum alloy after heating up to 300 °C

The influence of sealing methods on cracking tendency of anodic films on 2024 alloys after heating was studied. The anodic films were sealed by the methods of ambient water, boiling water, nickel fluoride and potassium dichromate, respectively. The results showed that the sealing mechanisms had important effects on initiation of cracks in anodic films during sealing process. The condensation of sealing products resulted in cracking of anodic films during sealing in boiling water, nickel fluoride solution and ambient water. On heating, the thermal stress was released mainly by widening and deepening of the originally initiated cracks during sealing. The cracks may penetrate through the anodic films and have detrimental effect on corrosion resistance of the films. The dichromate sealed anodic film showed an obviously decreased cracking tendency, which was attributed to the lower hydration extent and the opening pores during sealing process. Even after heating, there was no crack observed in the film. The result suggests that an “opening sealing” mode is beneficial to decrease the cracking tendency of anodic films during sealing and heating processes.     

Electrochemical behaviors of anodic alumina sealed by Ce-Mo in NaCl solutions

1 Introduction Aluminum is a kind of material with active chemical behavior. It can form a thin oxide film on its surface in natural environment. The structure of this amorphous film is loose, so it could not provide good corrosion resistance. Anodizing i…     

镁合金阳极氧化膜在NaCl溶液中的腐蚀行为

利用盐水浸泡实验研究了AZ91D镁合金阳极氧化膜层在3．5％NaCl溶液中的腐蚀行为。结果表明：AZ91D镁合金阳极氧化膜层不论封闭与否,在中性NaCl溶液中浸泡出现第一个腐蚀点后,膜层表面均很少再出现新的腐蚀点,而是原有的腐蚀点向纵、横两个方向扩展形成腐蚀坑,表面呈“树枝”状腐蚀形貌;浸泡溶液的pH值对阳极氧化膜层的耐蚀性影响很大,酸性溶液中的腐蚀速率明显大于中、碱性溶液的;随浸泡溶液温度的升高阳极氧化膜层的腐蚀速率加快。据此,提出了AZ91D镁合金阳极氧化膜层在NaCl溶液中腐蚀过程的模型。     

铈盐对铝合金硼酸?硫酸阳极氧化膜的封闭效应

将铝合金硼酸-硫酸阳极氧化膜浸入铈盐转化液中进行封闭。采用交流阻抗谱技术研究各封闭参数对氧化膜耐蚀性的影响,比较了不同方法封闭的氧化膜的耐蚀性差异。结果表明:将硼酸-硫酸阳极氧化试样浸入30℃的铈盐转化液(5 g/L Ce(NO3)3+0.5%H2O2)中处理30 min后,多孔层电阻Rp大幅增加,且腐蚀电流密度降低1个数量级,耐蚀性明显优于沸水封闭氧化膜的,也稍优于稀铬酸封闭氧化膜的耐蚀性。结合EDS分析表明:铈盐转化封闭后硼酸-硫酸阳极氧化膜的外表面形成了一层完整致密的铈盐转化膜,多孔层内也充满了铈的封闭产物,二者的协同作用几乎完全封住了硼酸-硫酸阳极氧化膜的孔隙,从而有效地提高了氧化膜的耐蚀性。     

EIS evolution of anodised aluminium by cerium salt sealing in NaCl solution with exposure time

Abstract

The sealing of porous anodic oxide film on aluminium 2024 involving immersion of the anodised aluminium in an aerated solution containing cerium salt under the application of pulse power at room temperature has been proposed as an alternative to dichromate sealing method. The sealing process shows some advantages. The corrosion behaviours of the anodised aluminium unsealed or sealed by dichromate and cerium salt respectively were investigated at different exposure times up to 30 days in 1M NaCl solution by means of electrochemical impedance spectroscopy, and the damage functions were calculated in this work. The results show that the damage functions of anodised aluminium sealed with cerium salt are lower than those unsealed or sealed with potassium dichromate. Cerium salt sealing provides a better corrosion resistance of anodised aluminium in NaCl solution for long exposure time than dichromate sealing.