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DMF中脉冲电沉积Nd—Co合金膜 总被引:1,自引:0,他引:1
研究了室温下在含有少量水的NdCl3-CoCl2DMF溶液中Nd-Co功能合金膜的电沉积。应用脉冲电镀制备出不同质量的合金膜。试验结果表明:D 0.45mol/LNdCl3+0.05mol/LCoCl2+适量乙二胺的DMF电镀液中,控制脉电流密度为100-150A/m^2,可得到有金属光泽的灰色稀土合金膜。 相似文献
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pH对膜污染层EPS污染特征的影响及机理分析 总被引:1,自引:0,他引:1
溶液pH值不仅影响溶质的电荷等表面性质,同时也影响膜表面的特性,从而影响溶质与膜表面之间的相互作用和溶质在膜面的沉积量及膜通量.胞外多糖(Extracellular POlvsac-charides,EPS)是膜生物反应器(Membrane Bioreactor,MBR)中主要的膜污染物质之一,从实际MBR膜污染层中分离纯化得到的EPS,在EPS引起膜污染机理分析的基础上,以过滤阻力、EPS在膜表面沉积量及膜通量为评价指标,综合分析不同溶液pH对EPS污染特征的影响,可为揭示MBR中EPS膜污染的成因和机理以及污染膜的清洗提供参考.结果表明,MBR膜污染层EPS的膜污染过程较好地符合沉积阻力模型,EPS在膜表面的污染主要是EPS沉积引起的;EPS溶液的pH越高,其与膜之间的排斥力越大,沉积量越少,沉积阻力越小,膜通量越高.pH为7.0时,沉积阻力为3.34×10~(11) m~(-1),沉积量为1.25 g/m~2,初始相对膜通量为9.8%. 相似文献
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铜合金表面硝酸镧稀土钝化膜的性能研究 总被引:1,自引:0,他引:1
为了提高铜及其合金的耐蚀性能,研究了一种含硝酸镧的新型钝化工艺,处理后的铜合金表面形成了金黄色的稀土钝化膜.采用硝酸点滴、湿热试验及盐雾试验等方法对钝化膜的耐蚀性进行了表征.结果表明,最佳钝化工艺为:23 g/L有机羧酸,16 g/L苯并三氮唑(BTA),4 g/L硝酸镧,1 g/L促进剂,温度60℃,钝化时间3 min.稀土盐的加入使其耐硝酸点滴及湿热试验的时间均延长了3倍多;在5%NaCl溶液的腐蚀速率降低6倍,在扫描电镜下可以明显观察到加入稀土盐后合金表面结构变得均匀致密;电子探针分析表明,稀土钝化膜的La,O等元素都均匀分布在膜层表面. 相似文献
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镀锌钢板硅烷与稀土铈盐、镧盐复合钝化的性能及机理 总被引:3,自引:0,他引:3
试验采用γ-氨丙基三乙氧基硅烷(γ-APS)协同稀土铈盐和镧盐钝化镀锌钢板.通过先在试样表面自组装一层γ-APS薄膜,再沉积稀土转化膜制备硅烷稀土复合膜.采用电化学交流阻抗技术(EIS)、盐雾试验检测复合膜的耐腐蚀性,结果表明复合膜的耐腐蚀性和致密性相对于单一硅烷、稀土转化膜大幅度提高,其中硅烷-铈盐复合膜比硅烷-镧盐复合膜耐腐蚀,中性盐雾试验时间达到76 h.原子力显微镜检测结果表明,复合膜相对于单一稀土转化膜平整.EDS检测结果得出,硅烷与稀土化合物发生了协同作用,促进了稀土转化膜在锌表面沉积.初步探讨了复合膜的成膜机理和耐腐蚀机理. 相似文献
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目前将稀土用作电沉积Ni-Co合金添加剂时有关其对镀层耐蚀性的影响报道较少.通过X射线衍射、极化曲线和中性盐雾试验研究了稀土Ce对双脉冲电沉积纳米Ni-Co合金层晶粒尺寸及耐蚀性的影响,采用扫描电镜对有无稀土Ce的Ni-Co合金镀层盐雾腐蚀前后的表面形貌进行了观察.结果表明:无论是否添加稀土Ce,Ni-Co合金镀层均为面心立方结构,主要的晶面取向为(111)和(200)面;稀土Ce含量在一定范围时,细化了Ni-Co合金镀层的晶粒,镀层的自腐蚀电位正移,自腐蚀电流减小,耐蚀性增加,且加入量为0.6 g/L时晶粒尺寸最小. 相似文献
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《Current Opinion in Solid State & Materials Science》2015,19(2):77-84
Electrochemical methods are attractive for thin film deposition due to their simplicity, conformal and high rate deposition, the ability to easily make multilayers of different composition, ease of scale-up to large surface areas, and applicability to wide variety of different shapes and surface geometries. However, many elements from periodic table of commercial importance are too active to be electrodeposited from aqueous solution. Recent advances are briefly reviewed for room temperature methods for electrochemical deposition, including electrodeposition from ionic liquids, electrodeposition from organic solvents, combined electrodeposition and precipitation on liquid metal cathodes, and galvanic deposition. Recent studies of electrodeposition from ionic liquids include deposition of thick (40 μm) Al coatings on high-strength steel screws in a manufacturing environment; deposition of continuous Si, Ta and Nb coatings; and numerous interesting mechanistic studies. Recent studies of electrodeposition from organic solvents include Al coatings from the AlCl3–dimethylsulfone electrolyte, which demonstrate that additives can be employed to suppress impurity incorporation and to improve the deposit quality, and thick (5–7 μm) and continuous Si coatings from SiCl4 in acetonitrile. Galvanic deposition of Ti, Mo and Si coatings onto Al alloys has recently been reported, which is potentially much simpler and less expensive than electrodeposition from ionic liquids and organic solvents, but has complications associated with substrate consumption and coating adhesion. 相似文献
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研究了Zn-Al-Mg-Ce合金在长江水及3.5%NaCl(质量分数)盐水中的浸泡腐蚀性能,分别测试了其电化学性能,并与Zn、Zn-Al合金、Zn-Al-Mg合金做对比试验。采用扫描电镜和能谱分析了微观组织及成分,分析了耐蚀机理。结果表明:Zn-Al-Mg-Ce合金无论在长江水或3.5%盐水中都显示出电极电位最负、腐蚀电流最小、腐蚀速度最小,其腐蚀速度分别只有Zn的19.4%和23.7%,腐蚀速度由小到大依次为:Zn-Al-Mg-Ce相似文献
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在添加甘氨酸作为络合剂的水溶液体系中电沉积制备了Sm-Co薄膜,特征X射线谱(EDS)证明沉积膜由Sm、Co组成,X射线衍射分析表明Sm-Co膜为非晶态结构,扫描电镜观测结果显示,Sin-Co沉积膜表面颜色均匀,呈现银灰色但有裂纹和气泡.研究了沉积电压、主盐浓度配比、pH值、络合剂甘氨酸的添加等工艺参数对沉积膜的形貌及Sm含量的影响,结果表明,随着沉积电压的升高,沉积膜中Sm的含量先增加后减少,当沉积电压为1.5~2.0V vs.SCE时沉积膜的形貌最好,甘氨酸的添加对Sin-Co的形成有重要作用. 相似文献
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JEN SHEN RONGHUA LIU YING LIU ZULING JIANG QINGCHUN LI 《Journal of Materials Science》1997,32(3):829-832
Spray deposition is a new rapid solidification technique which produces bulk preforms directly from the melt metals. A spray
deposition process was used to develop several high-strength aluminium alloys based on their commercial chemical compositions.
These alloys include 2024 alloy, 7075 alloy and 7075 alloy modified with 1.0% Fe and 1.0% Ni.The deposits possessed rapid
solidification microstructure with grain size of about 20 μm and a relative density of over 94%. The hardening phases of the
materials in T4 or T6 conditions consisted of supersatured solid solution, stable and unstable ageing precipitates and disperse
phases. The formation of the fine distributed disperse phases was due to the addition of iron and nickel to the 7075 alloy.
The spray-deposited materials exhibited substantial improvement in tensile strengths and maintained acceptable ductility when
compared to the corresponding ingot metallurgy processed materials.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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R.S. Parzuchowski 《Thin solid films》1977,45(2):349-355
A gas phase aluminum deposition process was developed for nickel base alloys. The substrate to be coated is out of contact with a powder mixture which generates the gaseous transport agent. Gas diffusion was shown to be the factor controlling the aluminum deposition rate in the process for both internal and external surfaces. The aluminum deposition rate increased with decreasing partial pressure of the transporting agent. Complex aluminum halides of an alkali or alkaline earth metal were demonstrated to have sufficient “throwing power” to deposit aluminum uniformly on internal surfaces. 相似文献
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固溶处理对AM60B+xRE及AZ9lD+xRE镁合金性能的影响 总被引:24,自引:0,他引:24
研究了添加少量富铈混合稀土的AM60B xRE及AZ9lD xRE合金(x=0.4、0.8、1.2、1.6和2.0%,质量分数)固溶处理后的显微组织与机械性能.结果表明,添加混合稀土能显著提高合金的抗拉强度σb和屈服强度σ0.2,固溶处理明显提高AZ9lD xRE合金的强度;AM60B xRE及AZ9lD xRE合金的铸态组织由α(Mg)固溶体、杆状Al11RE3相、颗粒状Al10Ce2Mn7相以及网状Mg17Al12相组成,经过固溶处理后,网状Mg17Al12相完全溶解,只剩下热稳定性较高的Al11RE3相和Al10Ce2Mn7相,随固溶时间的延长,其形态略有改变.AM60B xRE合金拉伸试样断口呈带局部韧窝的准解理断裂形式,而AZ9lD xRE合金则呈现沿晶断裂 解理断裂的混合断口形态. 相似文献
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Perovskite type barium oxoplumbates can be grown at low temperatures via chemical synthesis from alkali hydroxide melts. Strongly oxidizing conditions and low K/Ba ratio lead to the formation of the ternary phase BaPbO3 whereas less oxidizing conditions and high K/Ba ratio favour the formation of the quaternary solid solution KxBa1−xPbO3−y with tetragonal symmetry. Mixed valence Pbll/PblV quaternary phases can similarly be prepared by anodic deposition from hydroxide melts in closed systems; partial substitution by rare earth ions is possible. Ternary and quaternary oxoplumbates can be reduced electrochemically in aqueous electrolytes at ambient temperature under formation of lead metal. 相似文献