High Purity Aluminum Research Articles

Aluminum coatings were electrodeposited on copper substrates using a chloroaluminate-based ionic liquid electrolyte composed of AlCl3 and [Bmim]Cl, employing both direct current (DC) and pulse reverse current (PRC) modes at a current density of 5 mA cm−2. Structural and surface characterizations using X-ray diffraction, field-effect scanning electron microscopy, atomic force microscopy, energy-dispersive spectroscopy, and inductively-coupled plasma optical emission spectroscopy revealed that PRC mode deposition resulted in finer grain size (29 nm), smoother surface topography (Ra ∼4.2 nm), and more uniform coatings compared to DC mode (grain size 32 nm, Ra ∼14.2 nm). Both deposition modes produced high-purity aluminum (>99.997%) with minimal trace impurities. Electrochemical analyses in 3.5 wt.% NaCl demonstrated that PRC mode deposited coatings exhibited improved corrosion resistance, as indicated by lower corrosion current density (0.0012 μA cm−2), higher charge transfer resistance, and reduced donor density in the passive film. These findings highlight the advantages of PRC mode electrodeposition in achieving defect-minimized, high-purity aluminum coatings with enhanced corrosion performance under low-temperature conditions.

Positron Annihilation Lifetime Spectroscopy (PALS) is a powerful technique for detecting microstructural defects in various material classes. In a commonly used 180^∘ detector configuration equipped with plastic scintillators, measurement accuracy is mainly affected by simultaneous detection of 1275 keV and 511 keV gamma quanta in the same detector. This study introduces an optimization approach that significantly improves spectra quality without requiring hardware modifications. By systematically adjusting the upper threshold of the start window in the Pulse Height Spectrum (PHS), this method effectively reduces unwanted 1275/511 piled-up events. Experimental validation with high purity aluminium samples demonstrates that lowering this threshold effectively suppresses corrupted coincidences, yielding extracted characteristic lifetimes closer to those from a 90° configuration. While a reduced upper threshold slightly broadens the instrument response function (IRF) due to an effectively reduced number of scintillation photons, the overall impact on timing resolution remains negligible. This approach enhances the reliability of PALS measurements while still preserving the benefits of a 180° configuration, i.e. high solid-angle efficiency.

Synthesis of high-purity aluminum via carbothermic reduction in microwave plasma for trimethylaluminum production

High purity aluminum in its bulk form has intrinsicallyhigh reflectancein the far-ultraviolet (FUV) regime and finds utility in astrophysicalinstrumentation applications. However, bulk Al oxidizes rapidly inthe atmosphere, and its native oxide strongly absorbs and severelydegrades the observed FUV properties relative to bare Al. Varioustechniques have been investigated to produce coatings that inhibitaluminum oxide formation and lead to high FUV mirror reflectance.This work examines the development and use of a uniquely modified,hybrid plasma-enhanced atomic layer deposition (PEALD) system to passivatealuminum mirrors with metal fluoride films. This system combines twoplasma sources in a commercial atomic layer deposition (ALD) reactor.The first is a conventional inductively coupled plasma (ICP) sourceoperated as a remote plasma, and the second is an electron beam (e-beam)driven plasma near the mirror surface. To establish the operatingconditions for the in situ e-beam plasma source, the effects of samplegrounding, SF6/Ar flow, and sample temperature on resultingAlF3 films were investigated. Optimal operating conditionsproduced mirrors with excellent FUV reflectivity, 92% at 121 nm and42% at 103 nm wavelengths, which is comparable to state-of-the-artAlF3-based passivation coatings and matches that of previouslyreported ex situ e-beam plasma-processed mirrors. This optimized insitu e-beam process, along with XeF2 passivation, is thenexplored to produce a clean seed layer (unoxidized Al surface) forsubsequent PEALD of AlF3. Both approaches are demonstratedas valid pretreatments before PEALD of AlF3, showing apromising pathway for the deposition of other fluoride-based layers,such as MgF2 or LiF, with ALD or PEALD.

Mechanical behavior and microstructure evolution of high-purity aluminum with different grain sizes under shock loading

Preparation of high-purity alumina ceramics with high-performance by powder metallurgy

Fabrication of high-purity alumina particles by spray drying and surface modification with SDS for methylene blue removal

Value adding to acid mine drainage: Synthesis of high purity alumina and recovery of gypsum

With the surge in global demand for sustainable materials, zeolite has shown irreplaceable value in the fields of environmental remediation, green catalysis and new energy storage due to its unique pore structure and versatility. However, traditional zeolite synthesis relies on high purity silicon and aluminum raw materials and high energy consumption process, which is not only costly, but also aggravates resource consumption and carbon emissions. To this end, this study focuses on sustainable zeolite synthesis technologies and systematically reviews their innovative processes, industrial applications and contributions to carbon neutrality goals. The results show that the solid waste based molecular sieve has great application value. The transformation of inexpensive source materials and waste can provide lucrative zeolites with qualities akin to those of commercially synthesized zeolites. Currently, zeolite synthesis technology has evolved from the conventional hydrothermal method to include microwave-assisted hydrothermal synthesis, the molten salt method, and alkali fusion hydrothermal method, which markedly enhances efficiency and diminishes energy consumption. However, large-scale production still faces challenges such as high equipment costs, raw material volatility and by-product generation. The future needs to focus on green scale technology to promote the transformation of zeolite from laboratory innovation to industrial grade solutions.

This study examined machinability aspects in terms of the main cutting force and surface roughness in dry CNC turning of graphene-reinforced composite aluminum with 0.5 wt%. The cutting speed, feed rate and depth of cut influence were investigated in regard to the responses of main cutting force Fz and surface roughness Ra when turning high-purity aluminum (Al 96.83%) and graphene-reinforced aluminum with 0.5% graphene nanoplatelets for comparative analysis. A customized central composite design of the experiments with nine runs was established, and the results were assessed through analysis of variance and response surface regression. Full quadratic prediction models were generated based on the experimental results and they were examined for their validity and efficiency in predicting the response of the main cutting force and surface roughness of the machined graphene-reinforced composite aluminum. The NSGA-II algorithm was finally applied for simultaneously minimizing the main cutting force and surface roughness by providing a well-spread Pareto front of non-dominated solutions. The results indicated that the feed rate was the dominant parameter affecting both objectives, namely the main cutting force and surface roughness, while the NSGA-II algorithm was capable of delivering advantageous solutions for enhancing machinability with less than 10% error predictions when comparing simulated and actual machining results.

This study introduces a green synthesis strategy for producing high-purity alumina (≥99.99%) through the controlled hydrolysis of aluminum isopropoxide, coupled with a novel impurity removal protocol to address persistent challenges in conventional methods, such as residual silicon/iron impurities and particle agglomeration. The experimental results indicate that La2O3, 1-(2-pyridylazo)-2-naphthol (PAN), and phenolphthalein exhibit effective removal capabilities for silicon/iron impurities. The addition of 1 wt% La2O3 reduces silicon content from 99.7 ppm to 16.4 ppm, whereas 0.6 wt% PAN and 0.2 wt% phenolphthalein, employed as iron-binding agents, lower iron content from 66.4 ppm to 20.7 ppm and 9.7 ppm, respectively. Through optimized dropwise hydrolysis and subsequent calcination at 1200 °C for 4 h, nanosized alumina powders with uniform morphology and controlled particle sizes (274-832 nm) were successfully synthesized. The proposed method offers a scalable and efficient pathway for synthesizing high-purity alumina with tailored particle characteristics.

High-purity aluminum is widely used in metallurgy, microelectronics and chemical synthesis. In this work, the method of carbothermic reduction of aluminum powder in a microwave plasma discharge with the formation of valuable organic products such as synthesis gas, acetylene and benzene was used. Al powder was studied by inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The yield of by-products was studied by gas chromatography equipped with a mass spectrometer, as well as optical emission spectroscopy of plasma discharge. High-purity aluminum powder reduced with the plasma was used to synthesize oxygen-free trimethylaluminum (TMA). For the first time, TMA was synthesized in one vacuum cycle without the system depressurizing to improve the purity of the final product. Trimethylaluminum was analyzed by gas chromatography, which confirmed that the main substance is ≥99.99% pure. Gas chromatography with a mass spectrometer was used to determine by-products and residual reaction products. Additionally, ICP-MS was used to confirm trace metal concentrations, achieving the 7N standard for ultra-high-purity materials.

Experimental and simulated analysis of the dielectric performance of high-purity alumina

Optimizing High Purity Aluminum Extraction from Bauxite: A Comprehensive Hydrometallurgical Approach

Zone-melting for efficient impurities removal and high-purity aluminum recovery from 7000 series computer numerical control machining scraps.

Solid waste encompasses various materials discarded from homes, industries and construction including organic, paper, plastic, metal, glass and hazardous waste. Recycling is crucial for environmental preservation, involving the collection, processing and conversion of waste into reusable materials, mitigating greenhouse gas emissions and conserving landfill space. Bauxite, treated with alkaline leaching, yields aluminium and derivatives. Accumulation poses environmental risks, leaching harmful substances. Despite hazards, it is a valuable alumina source. Processing is challenging; remelting with salts recovers metal. A complex method involves soda-roasting, alkali leaching and purification, with around 90% alumina recovery. Chemical recycling is a key advantage. Resulting aluminium hydroxide is primarily bayerite. The aluminium hydroxide was then put through calcinations, resulting in the formation of high purity alumina, aluminium chloride, aluminium sulphate water purifiers, steel making accelerators, building materials, refractory materials, composite materials etc. The study involved examining the characterization of SAD and its refined products through a range of analytical techniques including thermodynamic analysis, X-ray diffraction analysis, X-ray fluorescence spectroscopy, Fourier transform infrared analysis and chemical analysis respectively. The results show that aluminium dross is not only be used only to efficiently extract high purity alumina compounds, but also to effectively achieve the green disposal of toxic components in SAD and to achieve its high-value utilization and thereby avoiding stockpiling.

Aluminum alloys are widely used in transportation industries due to their excellent specific strength, stiffness, and formability. Modifying the texture of aluminum alloys can further enhance their mechanical properties. This study explores the hot deformation behavior of high-purity aluminum single crystals (ASCs) with Brass and Goss orientations. We examine the influence of crystal orientation on deformation mechanisms and establish hot processing maps to identify optimal conditions for microstructural evolution. The results highlight the distinct behaviors of Goss- and Brass-oriented ASCs, with Goss exhibiting greater dynamic recrystallization potential and Brass showing higher strain rate sensitivity at elevated temperatures.

Etching methods of aluminum foils used in electrolytic capacitors are selected based on the operating voltages, with DC and AC etching typically used for the anode foils of high- and low-voltage capacitors, respectively. The initial pits continue to grow and eventually form tunnels or cubic pits by DC or AC etching, respectively. This paper describes the pit formation and growth process, focusing on the involvement of passive film inside the pit and facet dissolution. In particular, it is found that high-purity aluminum foil containing Ti promotes the formation of passive film (etch film) inside pits during the cathodic half cycle of AC etching, and Cu promotes facet dissolution. These behaviors significantly affect the surface area expansion by electrolytic etching. In addition, the effects of crystal orientation, surface defects associated with oxide film crystallization, and a trace element, Pb, as factors affecting the pit initiation sites will be discussed.

Abstract Erbium-containing advanced aluminum alloys, such as 5E61, 5E83 and 7E75, have received widespread attention aluminum industrial chains due to their better comprehensive performance, including strength, plasticity, heat resistance and corrosion resistance. Then a rapid quantitative requirement for erbium content with a weight fraction of 0.08% to 0.30% has been proposed. Unfortunately, there is a lack of relevant analysis method both domestically and internationally. In order to solve the trouble, a method for determination of erbium in aluminum alloy was studied and established based on plasma optical emission spectrometry. The optimized conditions were as below: radio frequency power of 1.2 kW, atomized gas flow of 0.80 L•min−1, plasma gas flow of 12.5 L•min−1. The axial observation mode and 369.625 nm analysis line were selected. Sample of 0.10 g was accurately weighed to dissolve with high-purity water of 5.0 mL, hydrochloric acid of 5.0 mL and nitric acid of 1.0 mL. Then diluted to 100 mL. The calibration curve was established by the matrix matching with high-purity aluminum, which was a linear equation with a correlation coefficient of 0.9999. The limit of quantification was 0.0014%. The optimized method was applied to determine the actual samples, with the relative standard deviations were no more than 2.4%, and the recovery rates of erbium were from 96% to 101%. The determination results of the simulated sample were consistent with the theoretical value. The work provided a rapid quantitative method for microalloying erbium determination in aluminum alloys, that would be beneficial for the research and application of erbium-containing advanced aluminum alloys.

Segregation of Lead on High Purity Aluminum Foil for Electrolytic Capacitors