Anodic-Spark Layers Formed on Aluminum Alloy in Tungstate-Borate Electrolytes

The effect of sodium tungstate concentration in 0.4 M H₃BO₃ on the sparking voltage, thickness, and the phase and elemental composition of coatings formed on AMtsM aluminum alloy (98% Al) by anodic-spark oxidation in a galvanostatic mode (i = 3 A dm²) was studied.     

Effect of the Polyphosphate/Me Molar Ratio in an Aqueous Electrolyte on the Composition of Anodic-Spark Layers at Aluminum Alloys

The manner in which the molar ratio n = [sodium polyphosphate]/[Me cation] in aqueous electrolytes is related to the thickness h and the element content (EC) of anodic layers formed on aluminum and its alloys during electric microbreakdowns (sparks, microarcs) is established. The polyphosphate structure, the electrolyte pH, and the nature and charge of Me cation do not affect dependences of EC and h on n in the case of Mn(II), Pb(II), Mg(II), Zn(II), Ni(II), Y(III), and Eu(III). The film growth mechanism changes with n. The incorporation of P, Me(II), or Me(III) is due to thermolysis of precipitate from electrolyte containing hydrated polyphosphates of Me(II) or Me(III), the thermolysis occurring at the anode under the action of electric breakdowns.     

Anodic-Spark Oxidation of Aluminum Alloy in Tungstate Electrolytes

The effect of Na₂WO₄ concentration, electrolyte depletion, and replacement of sodium tungstate by ammonium paratungstate on the specific features of formation and on the phase and elemental composition of coatings formed on AMtsM aluminum alloy in anodic-spark oxidation was studied.     

Anodic-Spark Deposition of P- and W(Mo)-Containing Coatings onto Aluminum and Titanium Alloys

Data of ^{3 1}P NMR spectroscopy, conductometry, and pH-metry, and results of experiments on Na₂WO₄ replacement with Na₂H[PW_{1 2}O_{4 2}] were used to study the relationship between the joint and proportional incorporation of P and W (Mo) into coatings, on the one hand, and the presence of heteropolyoxo anions in the electrolyte, on the other.     

Characteristics of Plasma-Electrolytic Oxide Coatings Formed on Aluminum and Titanium in Electrolytes with Siloxane Acrylate and Particles of Vanadium,Boron, and Aluminum Oxides

It is shown that aqueous suspension-emulsion electrolytes containing sodium silicate, siloxane-acrylate emulsion, and dispersed particles of oxides are promising for direct synthesis by the plasma-electrolytic oxidation method of coatings with multicomponent composition on titanium and aluminum. The formation processes, composition, and structure of the coatings were studied in electrolytes with 1–4-μm particles of V₂O₅, B₂O₃, or Al₂O₃. The average content of metals and nonmetals of dispersed particles in the surface part of the coatings is ~1–2 at %. The coatings have a developed surface morphology and contain in the surface part up to 50–73 at % carbon.     

Phase Composition of Coatings Formed on Titanium in Borate Electrolyte by Microarch Oxidation

The effect of oxidation conditions, temperature and concentration of the electrolyte, and its transformation from the true to colloidal solution on the phase composition and electrical resistance of coatings was studied.     

Influence of the Composition of Dilute Nickel-Plating Electrolytes on the Physicomechanical Properties of Electroplated Coatings

The influence of the composition of dilute nickel-plating electrolyte containing luster-forming additives on the leveling, plasticity, and internal stresses of coatings being electroplated was studied. The possibility of combining nickel sulfate, sodium chloride, and boric acid as the main composition of a dilute nickel-plating electrolyte was analyzed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 572–574.Original Russian Text Copyright © 2005 by Binkauskene.     

Kinetics of Anodic Dissolution of Some Metals in Electrolytes Based on Complexes of Triethylaluminum with Alkali Metal Fluorides and Tetraethylammonium Chloride

The dissolution kinetics of M* anodes (M* = Al, Cd, Sn, Sb, Bi) during electrolysis of molten complexes M[Al₂Et₆] (M = Na, K, Rb, Et₄N; = F, Cl) is studied. Parallel dissolution paths are discovered: through a limiting discharge of electrolyte components and through a limiting electrooxidation of adatoms and clusters of M* present at the electrode surface. Substantiated is a mechanism of electrosynthesis of ethyl derivatives M*Et _n involving the formation of adsorbed complexes (M*Et_{1 k n – 1})_ads via the scheme AlEt₄ ^– + M* – e M*(Et)_ads + (AlEt₃); M*(Et)_ads + (AlEt₄ ^–) – e = M*(Et₂)_ads + (AlEt₃); ...; M*(Et _{n – 1})_ads + (AlEt₄ ^–) – e AlEt₃ + M*Et _n .     

Effect of ac Polarization on Characteristics of Coatings formed from Polyphosphate Electrolytes of Ni(II) and Zn(II)

Characteristics of microplasma-produced coatings formed on an aluminum alloy under anodic and combined anodic-cathodic polarizations in electrolytes with polyphosphate complexes of Ni(II) and Zn(II) are compared.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 253–259.Original Russian Text Copyright © 2005 by Boguta, Rudnev, Terleeva, Belevantsev, Slonova.     

Anodic Dissolution of Titanium Alloys in Hydrofluoric-Sulfuric Acid Electrolytes with Additives

Anodic dissolution of VT1-0, VT6, VT16 titanium alloys in hydrofluoric-sulfuric acid solutions with addition of alkali metal fluorides, glycerol, hexamethylenetetramine, and remantadine was studied in a wide range of potentials.     

Adsorption of Kryptate Complexes of Alkali Metals in Electrolytes of Different Compositions and in the Presence of 1-Adamantanol

Data on the adsorption of kryptates of alkali metals on a mercury electrode are obtained for the first time by a method of the measurement of the differential capacitance as a function of potential and are compared to one another. Shown is that there takes place a deep mutual relationship between the structure of a complex and the regularities of its adsorption. An assumption is put forth about the possibility of adsorption of a free ligand in solutions of lithium kryptate, which possesses relatively low strength. The co-adsorption of sodium kryptate with 1-adamantanol, which forms a two-dimensional condensed layer, is investigated. Established is that the C vs. E curves, obtained in 1 M Na₂SO₄ at a constant activity of 1-adamantanol and a varying concentration of Kryptofix^R 222, exhibit two distinctly pronounced portions, each of which corresponds to predominant adsorption of one of the surface-active components. The region of predominant adsorption of Kryptofix^R 222 expands with its concentration.     

Complexes of Cyclohexadienones with Aluminum Bromide

Saturated and aromatic monofunctional ketones form with AlBr₃ only 1:1 adducts, -diketones bind 2 mol of AlBr₃, and methylated cyclohexadienones form both 1:1 and 1:2 complexes.     

含镓、锡的铝合金在碱性溶液中的活化机理

镓锡合金沉积于铝阳极表面 ,形成活化点 ,是铝阳极活化的根本原因 .简单的Al_Sn、Al_Ga二元合金在碱性介质中不能活化 .Al_Sn_Ga多元合金阳极溶解时 ,Ga、Sn溶解进入溶液 .锡离子首先还原沉积于铝阳极表面 ,镓离子又在沉积的锡上沉积 ,在铝合金阳极表面不断形成Ga_Sn合金活性点 .低溶点的合金由于其良好的流动性 ,以单个或多个原子的形式嵌入氧化膜 ,形成活性点 ,起到了局部分离氧化膜的作用 ,是铝合金阳极活化的关键     

贫水电解质体系制备多孔阳极氧化铝模板的研究

在有机溶剂为主的含草酸电解质中,研究了大孔径有序度高的阳极氧化铝(AAO)的一步法电化学制备.实验证实,电解质中水含量的降低能够有效抑制铝的电氧化速率和溶解速率,使得其氧化膜孔道的生长能够稳定进行,所得到的六方孔道排列有序度明显高于纯水溶剂制备的电解质体系下的产物.考察了水含量、有机溶剂种类以及电解质浓度对AAO模板孔道形貌的影响.结果表明,有机溶剂贫水电解质体系使得电氧化电压的选取范围比水溶液电解质体系更宽,孔径连续可调,反应条件温和.该方法适合于制备均匀大孔径的AAO模板.     

火焰原子吸收光谱法测定工业纯铝变形铝及铝合金中铁

在工业纯铝和大多数变形铝及铝合金中铁属于杂质,GB/T 3190-1996《变形铝及铝合金化学成分》[1]标准共规定了143个牌号的变形铝及铝合金的化学成分,其中133个牌号的铁属于杂质,在这些牌号中铁最高限量为0.003%~1.0%。因此,铝及铝合金中痕量或微量铁的准确测定极为重要。文献[2]采用经典的邻二氮杂菲分光光度法。此方法对显色试液pH值的控制要求较严格,测定大量样品耗时,对痕量铁的测定精密度较差。因此,本法用火焰原子吸收光谱法测定工业纯铝、变形铝及铝合金中铁。1试验部分1.1仪器与试剂180-80型塞曼偏振原子吸收分光光度计。试剂为分析…     

铝阳极氧化膜的半导体特性

The semiconductor properties of anodic oxide film formed on commercial pure aluminum were analyzed usingMott-Schottky theory and point defect model (PDM). The donor density, oxygen vacancy diffusion coefficient and flat-band potential were measured for the oxide films sealed by boiling water and K2Cr2O7, respectively. The results indicated that the anodic oxide films showed the n-type semiconductor property and the donor density decreased exponentially with the voltage elevating. The value of oxygen vacancy diffusion coefficient is about (1.12-5.53)伊10-14 cm-2·s-1. The flat-band potential of anodic oxide filmdeclined after sealing.     

Analysis of Corrosion Products Formed on Cu-Ni Alloys Immersed in Sea Water

Abstract

A method was developed for separation and analysis of corrosion products formed on the surface of Cu-Ni alloys immersed in sea water polluted by sulphide ions. This method is based on the selective dissolution of oxidation compounds by suitable solvents dissolving the metal matrix only to a negligeable extent.

The following solvents were used: 1) methanol to dissolve Na⁺, Cu²⁺, Ni²⁺ chlorides and sulphates; 2) glycine to dissolve bivalent metal compounds - Cu²⁺, Ni²⁺ oxides, sulphides, oxysulphates, oxychlorides and oxycarbonates; 3) ammonia solution to dissolve Cu⁺ compounds (i.e. Cu₂O and CuCl); 4) potassium cyanide to dissolve CU⁺ sulphides.

Reasonable agreement between chemical and X-Ray analysis results was observed only for copper compounds, since nickel and iron compounds could not tie observed by X-Ray diffraction. The results of Auger and chemical analyses better agree with each other, yet no Fe compounds could be detected. This is to be attributed to the non-homogeneous corrosion layer which notably contains Fe compounds in the innermost region at a depth where Auger spectroscopy is unable to detect them, whereas their detection is possible by chemical analysis, since it is a bulk analysis.     

铝合金熔体中气体的行为研究

分析了铝合金中氢的主要来源. 指出影响铝合金熔体中氢含量的因素有温度、氢压力、合金中Si及夹杂含量, 在一定的温度和氢压力下, 调整合金中Si含量并减少夹杂, 可有效防止合金中氢的过多进入. 要从根本上消除氢对铝合金造成针孔等缺陷, 必须在减少氢含量的基础上, 改变凝固状态下残余氢的存在形态, 稀土是有效的精炼熔剂, 对其固氢的作用机理、产物结构形态等问题尚需进一步深入细致的研究.     

X射线荧光光谱法测定铝合金及纯铝中痕量元素

根据X射线荧光光谱法分析样品形状要求,按照待测物料形状,适合于X射线荧光光谱测量的棒状类样品用车床车割,块、片状类样品用锯、锉刀处理,屑类样品首先用液压机压成片状,再用锉刀处理成适合于X射线荧光光谱分析的待测样品.测试了铝合金和纯铝中铁、硅、铜、镓、镁、锰、锌、钛和铬的含量,对于测量不灵敏的镁,每次测试带全套标样,峰值计量,单独为组测量可保障其准确度.基体单纯、固定的样品,测量痕量元素含量时峰值强度计量优于扣除背景的净强度计量,可避免背景测量误差,测量结果与直读光谱法相符.9项元素的精密度均优于3%.