Preparation and Performance of Rare Earths Chemical Conversion Film on Magnesium Alloy

Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morphology and performance of the conversion film were analyzed by means of SEM and electrochemical method. Formation dynamics about cerium conversion film on magnesium alloy in solution containing cerium salt and the anti-corrosion behavior of the conversion film in 3.5% NaCl solution were studied by electrochemical method respectively. The results shows that the conversion film is more compact at room temperature when concentration of cerium sulfate is 10 g·L-1 in the solution; the open circuit potential of the magnesium sample moves up to positive direction about 100 mV, the surface of conversion film becomes even and lustrous, and the adhesion intensity of conversion film increases when adding aluminum nitrate into the solution containing cerium salt. The pH value of the solution and immersion time of the sample in the solution also affect the surface morphology and anti-corrosion property of the conversion film. After covered by rare earths conversion film, the anti-corrosion property of magnesium alloy is obviously improved. Rare earth conversion film has self-repairing capability in corrosion medium.

Influence of Solution Composition on Formation of Golden Yellow Rare Earth Conversion Film on Magnesium Alloy

Cerium sulfate was used as main composite in solution to prepare golden yellow chemical conversion film on magnesium alloy. The influence of solution composition on the surface morphology of golden yellow rare earth conversion film on magnesium alloy was studied by means of SEM; potential-time curves in the formation process of rare earth conversion film and the anti-corrosion property of the conversion film were tested through ECT. The results show that, when there is no other component in the solution besides cerium sulfate, yellow film can be obtained on magnesium alloy, but there are some dusts on the film surface and the solution is not stable. The stability of cerium sulfate solution increases with adding hydrogen peroxide, while the film is thin and its color turn light. After adding combination additive containing Al 3+, smooth and compact golden yellow film was obtained on magnesium alloy. The polarization curves tested in 3.5% NaCl solution show that the anti-corrosion property of magnesium alloy is increased obviously by rare earth conversion film, and the film has self-repairing capability in the corrosion process.

Investigation of Formation and Inhibition Mechanism of Cerium Conversion Films on Al 2024 Alloy

To study the mechanism of formation and inhibition of Ce conversion films on Al 2024-T3 alloy, scanning microreference electrode technique (SMRE) is used to probe the potential map on Al 2024-T3 in CeCl 3 solution, the localized corrosion of Al alloy decreases with immersion time and disappears finally, which results from the competition of Cl - aggression and Ce 3+ inhibition on alloy surface. The results of X-ray photoelectron spectroscopy (XPS) indicate that the Ce conversion films consist of Al 2O 3, CeO 2 and Ce 2O 3(Ce(OH) 3), and CeO 2/Ce 2O 3 ratio decreases with the immersion time. When a critical pH for Ce(OH) 3 formation was reached, Ce(OH) 3 will precipitate on the micro cathodic area on alloy surface. Consequently, H 2O 2, the product of the catholic reaction will oxidize a part of Ce(OH) 3 to CeO 2, which appears a better corrosion resistance for Al alloys.

Deposition of cerium contained conversion films on LC4 alloy with square wave pulse method

Cerium contained conversion films were deposited on LC4 aluminum alloy usingsquare wave pulse (SWP) in a CeCl_3 solution with KMnO_4 as the oxidant. Energy dispersivespectroscopy (EDS) and scanning electron microscopy (SEM) were adopted to study the composition andthe morphology of the film. It is found that the film is composed of Al, Zn, Cu, and small amount ofcerium. The polarization curves of the specimens treated with SWP technique measured in 3.5% (massfraction) NaCl solution reveal that the film thus formed inhibits both the anodic and cathodicprocess of the corrosion of the specimen. The immersion tests of treated specimens in 3.5% NaClsolution indicate that the corrosion resistance of the SWP treated specimen is better than that ofthe untreated and is equivalent to or even better than that of the traditionally electro-chemicallytreated specimens.

Cathodic electrolysis method of depositing cerium conversion films on industrial pure aluminum

Two two-step techniques, called TS2/TS7 and TS3/TS7, respectively,have been developed to form cerium conversion films on the surface ofindustrial pure aluminum. The tested material was cathodicallyelectrolyzed in the al- kaline solution containing cerium salt, anduniform films containing cerium were obtained after the two-steptreatment. It is found that the films obtained by TS2/TS7 and TS3/TS7techniques are about 4.0 and 3.0 um in thickness, respectiv- Ely. Thematerial has better corrosion resistance in the chloride solutionafter the two-step electrolysis treatent compar- Ed with the one-steptreated and naked specimens.

Chemical Conversion Film of Mischmetal on Zinc Deposit

A conversion film was obtained on zinc deposit by immersing zinc coated specimens in a mischmetal salt solution. Several factors affecting the anticorrosive efficiency of the conversion film were studied. The suitable technological conditions were established. The composition and the thickness of the conversion film were determined by Auger electron spectroscopy(AES).

稀土转光膜对日光温室小环境、甜瓜生长、果实品质的影响

为稀土转光膜在设施蔬菜生产上的应用提供参考依据,以甜瓜嘉帅红星为试材,以普通高保温PO流滴膜为对照,研究在PO流滴膜基础上添加稀土转光材料母粒的稀土转光膜对日光温室内环境、甜瓜生长、果实品质的影响。采用OHSP-350UVCOHS光谱仪对棚膜透射光谱进行测定,使用SPAD-502型叶绿素计等仪器、HOBO无线蓝牙温光度记录仪、PAL-BXIAACID3系列ATAGO艾拓糖度计等测定棚膜的光学性能及其覆盖日光温室内小环境、甜瓜生长、果实产量和主要品质等指标。结果表明,与普通PO流滴膜相比,添加稀土转光剂的稀土转光膜增加了棚内蓝紫光的比例,降低了绿光、红橙光的比例,降低了稀土转光膜温室内平均光照度和日最高光照度,提升了棚室内平均空气湿度、日最低空气湿度,甜瓜开花、授粉期提前2 d,甜瓜产量提高14.4%,商品瓜率提升2.7%,裂瓜率降低23.5%。综上,与高保温PO流滴膜相比,稀土转光膜在日光温室甜瓜栽培上具有增强植物光合作用、促进植株生长发育的作用。

2198铝锂合金稀土铈化学转化膜的制备及耐蚀性研究

2198铝锂合金具有较高的比强度及比刚度,在航空航天领域有广泛应用,但其局部腐蚀敏感性较高,需进行适当的表面处理以提高其耐蚀性能。通过化学浸泡法将2198铝锂合金放入0.02 mol/L CeCl_(3)+0.029 mol/L H_(2)O_(2)水溶液中分别处理20、60 min,在其表面获得了稀土化学转化膜。使用扫描电镜(SEM)和能谱仪(EDS)观察和分析了稀土化学转化膜的形貌和成分;用X射线光电子能谱(XPS)分析了转化膜的元素价态;通过测试动电位极化曲线、电化学阻抗能谱(EIS)和Mott-Schottky(M-S)曲线研究了稀土化学转化膜在0.1 mol/L NaCl溶液中的腐蚀行为及耐蚀机制。结果表明:2198铝锂合金稀土化学转化膜由Ce^(4+)和Ce^(3+)的氢氧化物和氧化物、Al^(3+)的氧化物和少量的单质Cu组成,各元素在表面均匀分布;稀土化学转化膜由表面到内部氢氧化物含量减少,氧化物含量增加。处理20 min和60 min获得的稀土化学转化膜的厚度约为0.81μm和1.50μm。在0.1 mol/L NaCl溶液中,稀土化学转化处理能够抑制2198铝锂合金的阴极吸氧过程,降低合金的自腐蚀电流密度,提高合金的耐蚀性;在2198铝锂合金表面制备稀土化学转化膜能使合金的耐蚀性能提高;且与处理20 min的试样相比,处理60 min获得的稀土化学转化膜的耐蚀性较高。同时,稀土化学转化处理改变了合金的腐蚀机制,使与Cl~-吸附相关的感抗弧消失,这是由于具有n型半导体特征的稀土化学转化膜中的载流子密度降低,载流子密度呈现正电荷,不利于Cl~-的吸附。

Er^(3+) Doped BaTiO_3 Optical-Waveguide Thin Films Elaborated by Sol-Gel Method

Erbium doped BaTiO 3 optical-waveguide films on Pyrex substrate was elaborated successfully through sol-gel method. BaTiO 3 is well crystallized when the film is annealed at 650 ℃ in air circumstance. The so-prepared films with 13 layers have comparatively lower refractive index than bulk BaTiO 3, and it can support two TM and TE modes. Photoluminescence and up-conversion luminescence spectra proved the successful doping of rare earth ions.

稀土有机配合物转光农膜研究进展

介绍了稀土有机配合物的转光机理、单核及多核金属-有机配体的光色效应以及稀土有机配合物转光剂及转光农膜的研究进展,分析了影响稀土有机配合物转光农膜发光性能的因素,并对其未来发展方向进行了展望。

新型稀土转光膜对塑料大棚早春茬黄瓜生长的影响

为探索新型稀土转光膜在塑料大棚黄瓜上的应用效果,以津优315密刺黄瓜为试验材料、PO膜为对照(CK),研究了新型稀土转光膜(RPO)对塑料大棚黄瓜生长、光合特性和品质的影响。结果表明,RPO处理后10、20、30、40 d黄瓜的株高、茎粗、叶片数均显著高于CK,株高分别较CK提高了18.62%、17.02%、12.67%和10.16%,茎粗分别较CK提高了15.29%、11.33%、13.85%和12.84%,叶片数分别较CK提高了11.94%、10.69%、8.91%、8.12%。RPO处理后30、40 d黄瓜的叶面积显著高于CK,分别较CK提高了31.96%、19.64%。RPO处理后40 d黄瓜的叶绿素a和叶绿素b含量显著高于CK,分别较CK提高了14.46%和41.40%;RPO处理的初始荧光、最大荧光产量和PSⅡ最大光能转化效率均显著高于CK,分别较CK提高了4.58%、7.43%和2.53%;RPO处理黄瓜叶片的光合速率、蒸腾速率、气孔导度均显著高于CK,分别较CK提高了15.45%、13.82%和3.72%,胞间CO_(2)浓度较CK降低了1.20%;RPO处理的黄瓜果实可溶性蛋白含量和V_(C)含量均显著高于CK,分别较CK提高了15.00%和13.51%;2个处理黄瓜果实的游离氨基酸含量差异不显著,但RPO处理较CK提高了3.97%;RPO处理黄瓜果实的可滴定酸含量显著低于CK,较CK降低了26.47%。新型稀土转光膜可以促进黄瓜植株生长,提高光合效率,改善果实品质。

Composition and corrosion resistance of cerium conversion films on 2195Al-Li alloy

The Ce conversion films on 2195A1-Li alloy without and with post-treatment were studied and the corrosion resistance was evaluated as well. The surface morphology was observed by scanning electron microscopy （SEM）, and the chemical composition was characterized by X-ray photoelectron spectroscopy （XPS）. The corrosion behaviors of 2195A1-Li alloy and conversion coating were assessed by means of potentiodynamic polarization curves. The experimental results indicated that after post-treatment the surface quality was improved significantly. According to XPS, the conversion coating after post-treatment was mainly composed of CeO2, Ce203, Ce-OH and a little MoO3 and MOO2. The results of potentiodynamic polarization curves revealed that the conversion coating with post-treatment possessed better corrosion resistance than bare alloy and Ce conversion coating without post-treatment.

稀土配位化合物光转换剂的设计

本文对稀土配位化合物光转换剂的结构设计问题进行评述。

铝合金稀土转化膜碱性成膜工艺T3/T7的研究

采用正交实验方法得出了最佳成膜工艺Ｔ３／Ｔ７，利用线性极化、极化曲线测试、中性盐雾实验等对该工艺形成的膜层耐蚀性进行了研究，并对表面膜层的性能进行了一系列测试．结果表明：在ＮａＣｌ水溶液中的全面腐蚀速度可降低１０～２０倍，可通过５０４ｈ的中性盐雾试验；经该工艺处理后铝合金腐蚀的阴阳极过程都受到明显阻滞，且自然腐蚀电位负移，点蚀电位相对于自然腐蚀电位明显正移。

稀土配合物光转换剂研究的现状与展望

介绍稀土配合物光转换剂的研究状况及其在应用方面存在的问题，并预测其发展趋势。

AZ91D镁合金表面铈转化膜成膜工艺及其耐腐蚀性的研究

通过正交试验确定了AZ91D镁合金在CeCl3-H2O2体系中的最佳成膜条件.利用扫描电镜对转化膜进行形貌观察和成分分析,利用浸泡集气和电化学方法了膜层的耐腐蚀性能.结果表明,在最佳成膜条件下,形成的膜层均匀、致密.在3.5%NaCl溶液和0.15mol/LH3BO3/0.05mol/LNa2B4O7缓冲溶液中的动电位极化测试表明,最佳条件下铈盐转化处理可使合金的腐蚀电位正移,腐蚀电流密度明显降低,起到一定的防护作用.

Mg-Gd-Y-Zr合金表面铈转化膜制备及耐蚀性能

采用容量法研究了Mg-Gd-Y-Zr合金表面铈转化膜的耐蚀性能,通过正交试验获得在其表面制备铈转化膜的最佳条件:pH值为10.0,成膜时间为30min,成膜促进剂的浓度为0.05mol/L,成膜温度为25℃。其影响程度为pH值>成膜时间>成膜促进剂的浓度>成膜温度。比较了铈转化膜、铬酸盐转化膜及光板镁合金在3.5%NaCl溶液中的耐蚀行为。实验结果表明铈转化膜显著地提高了镁合金的耐腐蚀性能。

锌镀层表面混合稀土转化膜的研究

利用浸液法在锌镀层上获得混合稀土转化膜，研究了处理溶液的浓度、ｐＨ、温度、促进剂Ｈ２Ｏ２的含量及处理时间等因素对膜层耐蚀性的影响，从而确定了适宜的工艺条件。用俄歇电子能谱（ＡＥＳ）对膜层的组成。

镁合金双稀土转化膜及其耐蚀性能的研究

已有的铬酸盐转化膜技术因污染环境而被限制使用。采用硝酸铈和硝酸镧混合溶液对AZ31镁合金进行了双稀土转化处理,讨论了浸渍时间对转化膜耐腐蚀性能的影响。采用点滴试验、盐水浸渍试验和Tafel极化法评价了双稀土转化膜的耐腐蚀性能。结果表明,经过双稀土处理后,镁合金的变色时间由6s提高到79s;在3.5%NaCl溶液中转化膜的腐蚀速率是基体的1/5;转化膜的腐蚀电位提高了0.313V,腐蚀电流密度由4.03×10-2mA/cm2降为2.31×10-4mA/cm2;双稀土转化膜的微观形貌呈破裂的干泥状;双稀土转化处理提高了镁合金的耐蚀性能,随处理时间的延长耐蚀性呈先增加后降低的趋势。

用脉冲激光溅射法制备的Yb^(3+)和Er^(3+)共掺杂氟化物薄膜的上转换发光

脉冲激光溅射法 (PLD) ,作为一种制备高质量薄膜的方法 ,被广泛地用于制备超导、铁电等薄膜。用PLD法制备的Yb3+ 和Er3+ 共掺杂氟化物薄膜的上转换发光性质。在 978nmLD激发下 ,薄膜发出强烈的橙色光 ,用日立 -F45 0 0光谱仪测量了其上转换发光光谱 ,观测到了Er3+ 很强的2 H9/2 →4 I1 5/2 (4 0 8nm) ,2 H1 1 /2 →4 I1 5/2 (5 2 0nm) ,4 S3/2 →4 I1 5/2 (5 5 0nm)和4 F9/2 →4 I1 5/2 (65 0nm)跃迁发射峰。给出了上转换发光强度随激发强度的关系 ,分析了其上转换发光机制及紫色上转换发光增强的原因。