Effects of magnesium chloride-based multicomponent salts on atmospheric corrosion of aluminum alloy 2024

Atmospheric corrosion of aluminum alloy 2024 （AA2024） with salt lake water was simulated through a laboratory- accelerated test of cyclic wet-dry and electrochemical techniques. Effects of the soluble magnesium salt contained in the salt water were investigated by scanning electron microscope （SEM）, transmission electron microscope （TEM）, energy dispersive spectrometer （EDS）, electron probe micro analyzer （EPMA）, X-ray diffraction （XRD）, infrared transmission spectroscope （IR）, and atmospheric corrosion monitor （ACM）. The results showed that, with the deposition, atmospheric corrosion of AA2024 could occur when the relative humidity （RH） was lower than 30%. A main crystalline component of corrosion products, layered double hydroxides （LDH）, [Mg1-xAlx（OH）2]^x＋ Clx-·mH2O （LDH-C1）, was determined, which meant that magnesium ion played an important role in the corrosion process. It not only facilitated the corrosion as a result of deliquescence, but also was involved in the corrosion process as a reactant.

Electrochemical Deposition and Nucleation of Aluminum on Tungsten in Aluminum Chloride-Sodium Chloride Melts

Electrochemical deposition and nucleation of aluminum on tungsten electrode from AlCl3-NaCl melts were studied by cyclic voltammetry, chronopotentiometry and chronoamperometry. Cyclic voltammetry and chronopotentiometry analyses showed that Al （Ⅲ） was reduced at 200℃ in two consecutive steps in an electrolyte of molten AlCl3-NaCl system with a composition 52：48 molar ratio. The current-time characteristics of nucleation aluminum on tungsten showed a strong dependence on overpotentials. Chronoamperometry showed that the deposition process of aluminum on tungsten was controlled by an instantaneous nucleation with a hemispherical diffusion-controlled growth mechanism. The results could lead to a better understanding of the AlCl3-NaCl melt system that has technological importance in electrodeposition of metals as well as in rechargeable batteries.

Electrochemical behavior of tantalum in ethylene carbonate and aluminum chloride solvate ionic liquid

To investigate the electrochemical reduction mechanism of Ta(Ⅴ)in ethylene carbonate and aluminum chloride(EC-AlCl3)solvate ionic liquid,cyclic voltammetry experiments were conducted on a tungsten working electrode.Four reduction peaks were observed in the cyclic voltammogram of the EC-AlCl3-TaCl5 ionic liquid.The reduction peaks at-0.55,-0.72,and-1.12 V(vs Al)were related to the reduction of Ta(Ⅴ)to tantalum metal by three stages including the formation of Ta(Ⅳ)and Ta(Ⅲ)complex ions.The reduction of Ta(Ⅲ)to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10^-7 cm^2/s at 323 K,and the diffusion activation energy was 77 k J/mol.Moreover,the cathode products at 323 K were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and X-ray photoelectron spectroscopy.The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at-0.8 V for 2 h.

Preparation of Rod-like Aluminum Doped Zinc Oxide Powders by Sol-gel Technique Using Metal Chlorides and Acetylacetone Precursors

Al-doped ZnO(AZO) powders were prepared by using metal chloride precursors and the sol-gel technique. IR peaks observed at 1590 cm-1 and 1620 cm-1indicated the formation of metal chelate as a consequence of the addition of acetylacetone to the metal chloride solution. TG-DSC analysis of the AZO gels confirmed the formation of metal chelate as evidenced by the development of several weight loss peaks accompanied by the introduction of new endothermic peaks. The resulting AZO gels were annealed at 500, 600, and 800 ℃ to study the effect of annealing temperature. XRD and SEM results showed that crystallization of AZO gels takes place around 600 ℃. Hexagonal wurtzite structure was identified as the main phase for all the samples. In addition, small shift of the XRD(002) peak coupled with XPS results from the AZO powders confirmed the successful doping of the ZnO powders. Micron sized rod-like AZO powders were uniform in dimension and morphology and remained stable even at 800 ℃.

Effect of combination of ultraviolet radiation and biocide on fungal-induced corrosion of high-strength 7075 aluminum alloy

The effect of ultraviolet(UV)radiation and biocide benzalkonium chloride(BKC)on fungal-induced corrosion of AA7075 induced by Aspergillus terreus(A.terreus)was deeply studied using analysis of biological activity,surface analysis,and electrochemical measurements.Results demonstrated that the planktonic and sessile spore concentrations decline by more than two orders of magnitude when UV radiation and BKC are combinedly used compared with the control.UV radiation can inhibit the biological activity of A.terreus and influence the stability of passive film of AA7075.Except for direct disinfection,the physical adsorption of BKC on the specimen can effectively inhibit the attachment of A.terreus.The combination of UV radiation and BKC can much more effectively inhibit the corrosion of AA,especially pitting corrosion,due to their synergistic effect.The combined application of UV radiation and BKC can be a good method to effectively inhibit fungal-induced corrosion.

Role of Chloride Ion and Dissolved Oxygen in Electrochemical Corrosion of AA5083-H321 Aluminum-Magnesium Alloy in NaCl Solutions under Flow Conditions

Flow-induced corrosion consists electrochemical and mechanical components. The present paper has to assessed the role of chloride ion and dissolved oxygen in the electrochemical component of flow induced corrosion for AA5083-H321 aluminum-magnesium alloy which is extensively used in the construction of high-speed boats, submarines, hovercrafts, and desalination systems, in NaCI solutions. Electrochemical tests were carried out at flow velocities of 0, ：2, 5, 7 and 10 m/s, in aerated and deaerated NaCI solutions with different sodium chloride concentrations. The results showed that the high rate of oxygen reduction under hydrodynamic conditions causes an increase in the density of pits on the surface. The increase of chloride ions concentration under flow conditions accelerates the rate of anodic reactions, but have no influence on the cathodic reactions. Thus, in the current work, it was found that under flow conditions, due to the elimination of corrosion products inside the pits, corrosion resistance of the alloy is increased.

Improve Effluent Water Quality at Abu-Rawash WWTP Using Aluminum Chloride and Carbon Dioxide

This research involved attempting to improve water quality at the Abu-Rawash WWTP by using aluminum chloride (AlCl3) as a coagulant combined with injection of carbon dioxide (CO2). The Abu-Rawash WWTP is the main source of water quality degradation at the Rosetta branch, Egypt. Sewage samples were collected from the effluent of the grit removal chamber. Jar tests were performed to estimate the optimum pH value and the coagulant dosage required to obtain acceptable treatment. Eleven samples were prepared with equal dosages of aluminum chloride (10.0 mg/L) and different pH values. The optimal pH values for the elimination of the biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and turbidity ranged from 6.10 to 6.20 for the aluminum chloride. Results indicated that the appropriate AlCl3 dosage was 2.0 mg/L, especially at pH between 6.1 and 6.2. The results also showed that the AlCl3 was cost effective, especially after reducing pH value. It is also more cost effective than the other proposed solutions such as changing the effluent path of the Abu-Rawash WWTP to the desert.

Chloride Assisted Growth of Aluminum Nitride Nanobelts and Their Enhanced Dielectric Responses

Aluminum nitride （AlN） nanobelts were successfully synthesized in high yield through a chloride assisted vapor-solid process. X-ray diffraction, transmission electron microscopy, and selected area electronic diffraction demonstrate that the as-prepared nanobelts are pure, structurally uniform and single crystalline, and can be indexed to hexagonal wurtzite structure. The micro observations show that there exist no defects in the obtained nanobelts. The growth direction of the nanobelts is along [0001]. The frequency spectra of the relative dielectric constant and of the dielectric loss were measured in the frequency range of 50 Hz to 5 MHz. Analysis of these spectra indicates that the interface in samples has great influence on the dielectric behavior of samples. As compared with AlN micropowders, AlN nanobelts have much higher relative dielectric constant, especially at low frequencies at room temperature.

Chemical Modification of Cassava Starch by Transesterification Using Vegetable Oil/Aluminum Chloride

Chemical modification of cassava starch by transesterification of a vegetable oil(palm kernel oil)using aluminum chloride as a Lewis acid catalyst was achieved under relatively mild conditions(temperature 60–110°C;atmospheric pressure).The reaction was carried out without any additional solvent.The modified starch was characterized by degree of substitution(DS),FTIR,X-ray diffraction and thermal analysis.DS of 0.09 to 0.53 were obtained.The cassava starch presented an X-ray diffraction pattern of a type A starch.X-ray analyses showed that the reaction did not significantly affect the crystallinity of starch.The modified starch films(MStF)adsorbed less water than the reference native starch film(NStF)at all the relative humidities investigated.The MStF were also less soluble in water.The tensile tests showed an increase of the strength and a decrease of the flexibility of MStF compared to the reference NStF.The results showed that this chemical route could be used to increase the water resistance of starch-based materials.

Experimental Investigation of Inhibition Efficiency of Crocin for Chloride-Induced Corrosion of Aluminum Alloys

The use of Crocin, derived from the flowers of Crocus sativus, is investigated as corrosion inhibitor for the AA1050, AA5083, AA5754 and AA6082 aluminum alloys in chloride ions environment. Aluminum and aluminum alloys are subjected to corrosion in the aggressive environment of chlorides, so several green corrosion inhibitors, mostly of plant origin, with minimum impact on health and the environment have been examined. In this study, the inhibition efficiency of 1.25 mM Crocin in a 0.01 M NaCl corrosive solution was assessed via electrochemical corrosion techniques and gravimetric mass loss measurements of the aluminum alloys. The surface of the specimens was examined using Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Stereomicroscopy and Glossiness measurements. Experimental results reveal the protective anticorrosive action of Crocin for all aluminum alloys in the sodium chloride medium.

Direct spray pyrolysis of aluminum chloride solution for alumina preparation

The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyrolysis efficiency is higher than that of static pyrolysis process, and the reaction and evaporation process lead to a multi-plot state of the alumina products by spray pyrolysis. Aluminum phase starts to transform into γ-Al2O3 at spray pyrolysis temperature of 600 °C, which is about 200 °C lower than that of static pyrolysis process. The primary particle size of γ-Al2O3 product is 27.62 nm, and Cl content in alumina products is 0.38% at 800 °C for 20 min.

Current efficiency of recycling aluminum from aluminum scraps by electrolysis

Extracting aluminum from aluminum alloys in AlCl3-NaCl molten salts was investigated. Al coating was deposited on the copper cathode by the method of direct current deposition using aluminum alloys as anode. The purity of the deposited aluminum is about 99.7% with the energy consumption of 3-9 kW＆#183;h per kg Al, and the current efficiency is 44%-64% when the deposition process is carried out under 100 mA/cm2 for 4 h at 170 ＆#176;C. The effects of experimental parameters, such as molar ratio of AlCl3 to NaCl, cathodic current density and electrolysis time, on the current efficiency were studied. The molar ratio of AlCl3 to NaCl has little effect on the current efficiency, and the increase of deposition temperature is beneficial to the increase of current efficiency. However, the increase of current density or electrolysis time results in the decrease of current efficiency. The decrease of current efficiency is mainly related to the formation of dendritic or powder deposit of aluminum which is easy to fall into the electrolyte.

Aluminum neurotoxicity effects on intracellular Ca^(2+) homeostasis in the rat cerebral cortex

Studies have suggested that aluminum, a neurotoxic metal, is involved in the progression of neurodegenerative diseases. Previous studies have confirmed that aluminum influences intracellular Ca^2＋ homeostasis. However, it remains unclear whether aluminum increases or decreases intracellular Ca^2＋ concentrations. The present study demonstrated that Al^3＋ competitively binds to calmodulin （CAM）, together with Ca^2＋, which resulted in loss of capacity of CaM to bind to Ca^2＋, leading to increased [Ca^2＋]i. Al^3＋ stimulated voltage-gated calcium channels on cell membranes, which allowed a small quantity of Ca^2＋ into the cells. Al^3＋ also promoted calcium release from organelles by stimulating L-Ca^2＋αlc to trigger calcium-induced calcium release. Although Al^3＋ upregulated expression of Na＋/Ca^2＋exchanger mRNA, increased levels of Ca^2＋ and Na＋/Ca^2＋ exchanger did not maintain a normal Ca^2＋ balance. Al^3＋ resulted in disordered intracellular calcium homeostasis by affecting calcium channels, calcium buffering, and calcium expulsion.

Effects of Temperature and Pressure on Stress Corrosion Cracking Behavior of 310S Stainless Steel in Chloride Solution

310S is an austenitic stainless steel for high temperature applications, having strong resistance of oxidation, hydrogen embrittlement and corrosion. Stress corrosion cracking（SCC） is the main corrosion failure mode for 310S stainless steel. Past researched about SCC of 310S primarily focus on the corrosion mechanism and influence of temperature and corrosive media, but few studies concern the combined influence of temperature, pressure and chloride. on SCC of 310S stainless steel, prepared samples are investigated via For a better understanding of temperature and pressure＇s effects slow strain rate tensile test（SSRT） in different temperature and pressure in NACE A solution. The result shows that the SCC sensibility indexes of 310S stainless steel increase with the rise of temperature and reach maximum at 10MPa and 160~C, increasing by 22.3% compared with that at 10 MPa and 80 ℃. Instead, the sensibility decreases with the pressure up. Besides, the fractures begin to transform from the ductile fracture to the brittle fracture with the increase of temperature. 310S stainless steel has an obvious tendency of stress corrosion at 10MPa and 160℃ and the fracture surface exists cleavage steps, river patterns and some local secondary cracks, having obvious brittle fracture characteristics. The SCC cracks initiate from inclusions and tiny pits in the matrix and propagate into the matrix along the cross section gradually until rupture. In particular, the oxygen and chloride play an important role on the SCC of 310S stainless steel in NACE A solution. The chloride damages passivating film, causing pitting corrosion, concentrating in the cracks and accelerated SSC ultimately. The research reveals the combined influence of temperature, pressure and chloride on the SCC of 310S, which can be a guide to the application of 310S stainless steel in super-heater tube.

Protective Effect of Ginkgo Biloba Leaf Extract on Learning and Memory Deficit Induced by Aluminum in Model Rats

Objective： To examine the protective effect of Ginkgo biloba leaf extract （GbE） on learning and memory deficit induced by aluminum chloride （AlCl3）, and explore its mechanisms. Methods： The rat models with learning and memory deficit were induced by administering via gastrogavage and drinking of AlCl3 solution. And the model rats were treated with GbE at the dose of 50, 100, 200 mg/kg every day for 2 months accompanied with drinking of AlCl3 solution, respectively. Their abilities of spatial learning and memory were tested by Morris water maze, and the acetylcholinesterase （ACHE） activity in serum was assayed with chemical method, the AChE expression in hippocampus was observed by immunohistochemistry assay, and then quantitative analysis was done by BI 2000 image analysis system. Results： Learning and memory deficit of rats could be induced by AlCl3 solution （P〈0.01）, and AChE expressions in rats hippocampus were increased （P〈0.01）; GbE ameliorated learning and memory deficit and reduced AChE expression in rats hippocampus in a dose-dependent manner, while GbE significantly increased serum AChE activity at the dose of 200 mg/kg each day （P〈0.05）. Conclusion： GbE can ameliorate learning and memory deficit induced by AlCl3, which may be due to its inhibition of the AChE expression in hippocampus.

Removing Al from Rare Earth Chloride Solution by Method of Extraction

Using long-chain fatty acid as extractant, the process of removing the impurity element aluminum in the solution of praseodymium-neodymium chloride and the influence of extracting conditions were studied. The results show that the amount of aluminum can be decreased from 728 to 14 mg·L -1 that is the 98% of total in the solution of praseodymium-neodymium chloride by one-stage extraction under the condition as follows: the concentration of rare earth is 100～200 g·L -1, the organic phase is 20% fatty acid -10% isooctanol -70% kerosene (V/V), saponification number is 20% with dense ammonia, and the extracting equilibrium time is 5～15 min. Under the same conditions, the extraction ratio of aluminum in the system of fatty acid is 3～5 times of that in naphthene acid. The fatty acid extractant is distinctly better than naphthene acid.

Comparison of Three Aluminum Coagulants for Phosphorus Removal

That phosphorus has been removed more from water in purification process can result in higher grade of biological stability of the effluent tap water, especially for the water plant when using surface water source. This study conducted the experiments of phosphorus removal by three coagulants including aluminum chloride, aluminum sulfate and poly aluminum chloride. The results indicated that the poly aluminum chloride is the preferred one that could remove phosphorus up to 80%, followed by aluminum chloride and aluminum sulfate. The lowest proportion of aluminum quality to phosphorus quality is 63 as using poly aluminum chloride, followed by aluminum chloride and aluminum sulfate. It is suggested that the poly aluminum chloride should be the best option to remove phosphorus in water plant.

铝二次电池用RGO-S电极材料制备与性能研究

以氧化石墨烯与硫代硫酸钠为原料,通过一步水热法,制备还原氧化石墨烯-硫(RGO-S)电极,通过XRD、XPS、SEM、TEM、恒流充放电测试等手段对电极进行分析。结果如下:在RGO-S中硫元素主要为单质,单质硫与还原氧化石墨烯之间主要是以物理吸附的方式结合,主要以S2p3形态存在,小部分以S2p1形态存在。硫元素含量越高,初次充放电容量越高,循环性能越差。硫碳质量比为3:7的RGO-S复合材料具有最优性能,经过120次的充放电循环后放电容量回复到92%左右,在高倍率电流密度下放电容量保持在58.83mAh/g。

Effect of Friedel's salt on strength enhancement of stabilized chloride saline soil

In the field of soil stabilization, only calcium silicate hydrate(CSH) and ettringite(AFt) as hydration products have been reported to directly contribute to the strength enhancement of the soil. A chloride dredger fill, an artificial chloride saline soil, and a non-saline soil were stabilized by Portland cement(PC) and PC with Ca(OH)_2(CH) with different contents. A series of unconfined compressive strength(UCS) tests of stabilized soil specimen after curing for 7 d and 28 d were carried out, and the hydration products and microstructure of the specimens were observed by X-ray diffractometry(XRD), scanning electronic microscopy(SEM), and energy-dispersive X-ray analysis(EDXA). The results showed that the strengths of PC+CH-stabilized chloride saline soils were much higher than those of PC-stabilized soils. A new hydration product of calcium aluminate chloride hydrate, also known as Friedel's salt, appeared in the PC+CH-stabilized chloride saline soils. The solid-phase volume of Friedel's salt expanded during the formation of the hydrate; this volume filled the pores in the stabilized soil. This pore-filling effect was the most important contribution to the significantly enhanced strength of the PC+CH-stabilized chloride saline soils. On the basis of this understanding, a new optimized stabilizer was designed according to the concept that the chloride in saline soil could be utilized as a component of the stabilizer. The strength of the chloride saline soils stabilized by the optimized stabilizer was even further increased compared with that of the PC+CH-stabilized soils.

H2S Removal with Cupric Chloride for Producing Sulfur

A novel technology of removing H2S with cupric chloride solution was developed in this paper. Cupric as the form of CuS deposition, the CuS produced was then oxidized by excessive cupric ion in another reactor meanwhile cupric ion that has been consumed can be recovered by the oxidization of CuCl2- with oxygen in air,and the solution can be circulated. Moreover, the leaching kinetics of CuS by cupric ion was studied. The removal efficiency of H2S is close to 100%, and the required operating condition is mild. Compared with other wet oxidization methods, no raw material is consumed except O2 in air, the process has no secondary pollution and no problem of degradation and scale, and the absorbent is much stable and reliable.