Carbon Aluminum Research Articles

Alkaline potassium aluminum carbonate: A novel high-efficiency dry powder extinguishing agent with high heat-resistant

Alkaline potassium aluminum carbonate (KAl(OH)2CO3) has potential application as an active medium for dry powder fire extinguishing due to its special molecular structure. In this paper, the application of KAl(OH)2CO3 as a high-temperature resistant dry powder extinguishing agent is first discussed. Firstly, the pyrolysis kinetics of KAl(OH)2CO3 was explored using thermal analysis techniques, including model-free and model-fitting methods. The pyrolysis of KAl(OH)2CO3 can be divided into three stages, with E values of 357.7 and 244.8 kJ/mol for stage 1 and stage 3, respectively. Higher activation energy of KAl(OH)2CO3 (T5 wt%=550 K, Tmax=648 K) means that it will not be deactivated prematurely in the high-temperature region. Moreover, the fire-extinguishing performance of KAl(OH)2CO3 is much better than that of BC dry powder fire extinguishing agent, which can suppress n-heptane and aviation kerosene pool fires within 6.00 s and 7.21 s. The possible fire-extinguishing mechanism of KAl(OH)2CO3 is also proposed. Therefore, KAl(OH)2CO3 is expected to be a high-temperature resistant dry powder extinguishing agent, which solves the application of existing dry powder fire extinguishing agents in high-temperature areas such as aircraft engine compartments.

The Correlation of LVI Parameters and CAI Behaviour in Aluminium-Based FML.

An experimental analysis of mechanical behaviour for aluminium-based fibre metal laminates under compression after impact was conducted. Damage initiation and propagation were evaluated for critical state and force thresholds. Parametrization of laminates was done to compare their damage tolerance. Relatively low-energy impact had a marginal effect on fibre metal laminates compressive strength. Aluminium-glass laminate was more damage-resistant than one reinforced with carbon fibres (6% vs. 17% of compressive strength loss); however, aluminium-carbon laminate presented greater energy dissipation ability (around 30%). Significant damage propagation before the critical load was found (up to 100 times the initial damaged area). Damage propagation for assumed load thresholds was minor in comparison to the initial damage size. Metal plastic strain and delaminations are dominant failure modes for compression after impact.

СИНТЕЗ И СВОЙСТВА ОКСИДОВ АЛЮМИНИЯ И ИТТРИЯ ДЛЯ КЕРАМООБРАЗУЮЩИХ МАТЕРИАЛОВ

Effect of hydroxide precursor nature on the morphology of alumina derived by heat treatment of ammonium aluminium carbonate hydroxide NH4AlCO3(OH)2 was investigated. It was found that the use of aluminum hydroxide as the precursor leads to the formation of needle-like particles of the product, while during synthesis using hydrated alumina, alumina particles of isometric shape were obtained. The effect of ammonia sulfate (NH4)2SO4 on the BET surface area of ammonium aluminium carbonate hydroxide powders was shown.

Evaluating current effects of upcoming EU Carbon Border Adjustment Mechanism: Evidence from China's futures market

The European Union Carbon Border Adjustment Mechanism (EU CBAM) has already generated concerns worldwide. In this study, we investigate the reactions of the energy-intensive industries to legislative announcement of the EU CBAM. We employ the event study method to empirically examine the existence of the green paradox based on the steel and aluminum data from China's futures market. The empirical results provide strong evidence of a significant decrease in returns for steel rebar and aluminum futures. However, there exists a stronger effect on aluminum futures than steel rebar due to the higher export intensity and carbon emission of aluminum products. Theoretically, the responses from energy-intensive industries appear to be driven by three potential channels (production, storage, and consumption), but our empirical results suggest that only producers respond to the EU CBAM event. Moreover, we also find that the CBAM event subsidized aluminum's carbon dioxide emissions by around 24 RMB per metric ton by quantifying the effect size of the event on the futures prices. We recommend that policymakers shorten the implementation lag of climate policies and limit the potential for new production capacity to be added.

Atomically Resolved Structure of the Directly Bonded Aluminum–Carbon Interface in Aluminum–Graphite Composites by Solid-State Friction Stir Processing: Im plications for a High-Performance Aluminum Conductor

Atomically Resolved Structure of the Directly Bonded Aluminum–Carbon Interface in Aluminum–Graphite Composites by Solid-State Friction Stir Processing: Im plications for a High-Performance Aluminum Conductor

Preparation of sustained-release-type citric-acid-intercalated hydrotalcite and its application in oil-well cement

To address the problems of poor thermal stability and over-retarding of cement slurry by retarders, as well as the sensitivity to citric acid (CA) dosage and poor early strength of cement treated with hydroxycarboxylic acid retarders, CA-intercalated magnesium aluminium hydrotalcite (Mg/Al-CA-LDH, henceforth called CAIH) with a sustained-release effect was prepared by an anion exchange reaction between CA and magnesium aluminium carbonate layered double hydroxide (Mg/Al-CO3-LDH). The prepared CAIH exhibited good crystallinity and high thermal stability, and 39.92% CA could be inserted in the composite. Evaluation of the thickening and compressive strength of oil-well cement showed that the addition of CAIH effectively maintained the fluidity of the cement slurry and improved its early compressive strength. Furthermore, because of the seed effect of hydrotalcite and the microrelease of CA in CAIH, the synergistic effect of hydrotalcite and CAIH can promote the setting of oil-well cement: the effect was stable and the thickening curve was stable, indicating right-angle thickening.

An Aluminium Imide as a Transfer Agent for the [NR]2- Function via Metathesis Chemistry.

The reactions of a terminal aluminium imide with a range of oxygen-containing substrates have been probed with a view to developing its use as a novel main group transfer agent for the [NR]2- fragment. We demonstrate transfer of the imide moiety to [N2 ], [CO] and [Ph(H)C] units driven thermodynamically by Al-O bond formation. N2 O reacts rapidly to generate the organoazide DippN3 (Dipp=2,6-i Pr2 C6 H3 ), while CO2 (under dilute reaction conditions) yields the corresponding isocyanate, DippNCO. Mechanistic studies, using both experimental and quantum chemical techniques, identify a carbamate complex K2 [(NON)Al-{κ2 -(N,O)-N(Dipp)CO2 }]2 (formed via [2+2] cycloaddition) as an intermediate in the formation of DippNCO, and also in an alternative reaction leading to the generation of the amino-dicarboxylate complex K2 [(NON)Al{κ2 -(O,O')-(O2 C)2 N-(Dipp)}] (via the take-up of a second equivalent of CO2 ). In the case of benzaldehyde, a similar [2+2] cycloaddition process generates the metallacyclic hemi-aminal complex, Kn [(NON)Al{κ2 -(N,O)-(N(Dipp)C(Ph)(H)O}]n . Extrusion of the imine, PhC(H)NDipp, via cyclo-reversion is disfavoured thermally, due to the high energy of the putative aluminium oxide co-product, K2 [(NON)Al(O)]2 . However, addition of CO2 allows the imine to be released, driven by the formation of the thermodynamically more stable aluminium carbonate co-product, K2 [(NON)Al(κ2 -(O,O')-CO3 )]2 .

Combinatorial experiments for discovering Al-C thin films with high strength and ductility

Aluminum (Al) is one of the most widely used structural material in various technologically relevant applications due to its light weight and formability. However, these advantages have been overshadowed by its relatively poor mechanical properties. In this paper, we report theexceptional mechanical properties of aluminum-carbon (Al-C) thin films deposited by multiple source co-sputtering. In the first set of experiments, a high-throughput combinatorial approach was taken to investigate mechanical and electrical properties of a blanket of Al-C thin film deposited with a compositional gradient. Hardness increased along with carbon addition, but at the cost of reduced electrical conductivity. These measurements allowed rapid screening of Al-C films and showed that regions with ∼ 6at% carbon possess a good balance of mechanical and electrical properties (2.8 GPa and 142 Ω·nm). Micro-tensile experiments of freestanding Al, Al-C 6.4at%, and Al-C 10.3at% films were conducted to acquire tensile properties and understand the strengthening mechanism. Al-C films with 6.4at% and 10.3at% carbon both exhibited significantly increased yield stress over 300 MPa while retaining ductility. Unexpectedly, an upper yield followed by a fall in the stress was observed, which resembles the mechanical behavior of low-carbon steel. The unusual mechanical behavior of Al-C is attributed to formation of the Cottrell atmosphere. We also demonstrated that C impurities suppress stress-induced grain growth, which leads to improved microstructural stability during deformation. This paper demonstrates that carbon addition by co-sputter deposition is a viable approach for improving the strength and microstructural stability of Al thin films without loss in ductility.

Влияние природы гидроксидного прекурсора на морфологию порошков Al2O3

Effect of hydroxide precursor nature on the morphology of alumina derived by heat treatment of ammonium aluminium carbonate hydroxide NH4AlCO3(OH)2 was investigated. It was found that the use of aluminum hydroxide as the precursor leads to the formation of needle-like particles of the product, while during synthesis using hydrated alumina, alumina particles of isometric shape were obtained. The effect of ammonia sulfate (NH4)2SO4 on the BET surface area of ammonium aluminium carbonate hydroxide powders was shown.

Ratiometric Detection of Al Based on the Mixing of D‐penicillamine‐Functionalized Copper Nanoclusters with Pyridoxal 5’‐phosphate

AbstractThe excess accumulation of nonessential Al3+ in the human body can cause serious health problems, thus there is significant interest in the detection of Al3+. A new ratio fluorescent probe (RF‐probe) based on the mixing of red‐emitting D‐penicillamine (DPA) stabilized copper nanoclusters (DPA‐CuNCs) with pyridoxal 5’‐phosphate (PLP) was designed for sensitive and selective determination of Al3+. The −CHO group of PLP is expected to form an imine linkage with the free −NH2 group available of the DPA on the surface of DPA‐CuNCs. The content of Al3+ could be mensurated by the as‐prepared RF‐probe with a linear response in the range of 1.33–46.67 μmol ⋅ L−1, and corresponding limit of detection (LOD) was calculated to be 0.33 μmol ⋅ L−1. Moreover, the RF‐probe was successfully extended to the assay of Al3+ in aluminum carbonate chewing tablets, baking powder, pond water and drink water with satisfactory results compared to the standard atomic absorption spectroscopy (AAS).

Effect of SiO2 content on the oxidation resistance of SiO2–B4C-glass coating for alumina–carbon refractories

To improve the oxidation resistance of alumina–carbon refractories, SiO2–B4C-glass composite coating was prepared by slurry brushing method on the surface of refractories. Effect of SiO2 content on the oxidation resistance of the coating was studied. Oxidation resistance mechanism and failure reason of the SiO2–B4C-glass coating were discussed. Results showed that introducing SiO2 could increase viscosity activation energy and elevate the glass layer's viscosity at high temperature. With the increase of SiO2 content, the glass viscosity at high temperature gradually increased. When SiO2 content was too low, the glass exhibited smaller viscosity and larger fluidity, so the glass layer was easy to be washed away. When SiO2 content was too high, the glass phase with high viscosity and low fluidity could not uniformly cover on the surface of alumina–carbon refractories. The composite coating with SiO2 content of 55 wt% exhibited excellent oxidation resistance, which could effectively protect alumina–carbon refractories at 800 °C for 100 h with weight loss of only −1.721%. Excellent oxidation resistance of the coating mainly depended on the glass layer with good self-healing ability. With the extension of oxidation time, the coating thickness decreased, leading to the relatively poor self-healing ability and reduced weight gain rate of the coating.

Features of the Hydrosulfate Method for Processing Alumina-Containing Raw Materials in a Closed Reagent Cycle

The decrease in the availability of high-quality bauxites makes the processing of high-silica raw materials inevitable, and in this regard, it is necessary to develop acid–salt methods suitable for these ores. The purpose of the work was to study various stages of the hydrosulfate method for processing alumina-containing raw materials on the example of nepheline concentrate in order to investigate the possibilities of their improvement. A. The distribution of various macro- and meso-components of leaching between phases at the stage of isolation of ammonium alum depending on sulfate concentration were experimentally and theoretically studied. It was shown that, with an increase in the total concentration of sulfate in the equilibrium mother liquor, the concentration of main impurity components, including iron, in a solid phase decreases significantly. To obtain relatively pure alum, it was recommended to use ammonium hydrosulfate with a concentration of at least 4 mol/L. B. Different embodiments for further purification of alum were explored. It was found that the use of the recrystallization process in the presence of small additions of sodium thiosulfate reduces the content of iron impurities in alum by almost an order of magnitude. C. A method for isolating purer final product was demonstrated. Isolation of ammonium aluminum carbonate hydroxide (ASACH), as a precursor of high-purity alumina, using ammonium bicarbonate is currently the most promising method in the hydrosulfate technology. In combination with the process of recrystallization, the preparation of AACH makes it possible to eliminate the need for expensive methods of selective sorption or extraction for deep purification of aqueous solutions of alum.

Two-Dimensional Chiroptically Active Copper Oxide Nanostructures

Induction of chirality in colloidal nanomaterials has been of great interest in recent years due to the broad range of potential applications for these materials, including in biomedicine, sensing, and photocatalysis. However, the investigation of chirality induction in two-dimensional (2D) nanomaterials is currently at a very early stage, despite their potential unique properties and important applications. Here, we report the synthesis and characterization of chiroptically active 2D copper(II) oxide (CuO)-based nanomaterials for the first time. In our studies we demonstrate that postsynthetic treatment of copper- aluminium carbonate intercalated layered double hydroxide (CuAl-CO3 LDH) nanosheets with phenylalanine at room temperature under basic conditions results in the formation of two-dimensional chiral CuO nanosheets exhibiting strong circular dichroism signals, far beyond the onset of the characteristic signals of the initial ligands.

Recovery of carbon and cryolite from spent carbon anode slag of electrolytic aluminum by flotation based on the evaluation of selectivity index.

One of the main electrolytic aluminum production costs is the consumption of carbon anodes, and carbon anode slag is a common hazardous waste in the aluminum industry. In this work, electrolytic aluminum carbon anode slag was separated by flotation. Using the selectivity index (SI) as an indicator, the influencing factors of the carbon slag flotation process were optimized, and the separation performance of carbon and cryolite in the carbon anode slag was investigated. The raw carbon anode slag was ground for 40 min to achieve dissociation of the cryolite from the carbon, the optimized SI value was then used to determine the optimal flotation test conditions. The test results showed that the SI value under the optimal grinding flotation was approximately four times larger than the value of direct flotation. This indicated that carbon anode slag had a better flotation selectivity under the grinding flotation, which significantly improved the flotation performance.

Design of Economical and Achievable Aluminum Carbon Composite Aerogel for Efficient Thermal Protection of Aerospace.

Insulation materials play an extremely important role in the thermal protection of aerospace vehicles. Here, aluminum carbon aerogels (AlCAs) are designed for the thermal protection of aerospace. Taking AlCA with a carbonization temperature of 800 °C (AlCA–800) as an example, scanning electron microscopy (SEM) images show an integrated three-dimensional porous frame structure in AlCA–800. In addition, the thermogravimetric test (TGA) reveals that the weight loss of AlCA–800 is only ca. 10%, confirming its desirable thermal stability. Moreover, the thermal conductivity of AlCA–800 ranges from 0.018 W m−1 K−1 to 0.041 W m−1 K−1, revealing an enormous potential for heat insulation applications. In addition, ANSYS numerical simulations are carried out on a composite structure to forecast the thermal protection ability of AlCA–800 acting as a thermal protection layer. The results uncover that the thermal protective performance of the AlCA–800 layer is outstanding, causing a 1185 K temperature drop of the structure surface that is exposed to a heat environment for ten minutes. Briefly, this work unveils a rational fabrication of the aluminum carbon composite aerogel and paves a new way for the efficient thermal protection materials of aerospace via the simple and economical design of the aluminum carbon aerogels under the guidance of ANSYS numerical simulation.

Preparation of MgAl layered double oxides and its adsorption kinetics for ciprofloxacin hydrochloride in water

AbstractMagnesium aluminum carbonate hydrotalcites (MgAl‐LDHs) were prepared by a coprecipitation method using magnesium nitrate and aluminum nitrate as raw materials, and then calcined at high temperature to obtain hydrotalcite‐like MgAl layered double oxides (MgAl‐LDOs). With ciprofloxacin hydrochloride as the target pollutant, and the adsorption kinetics of ciprofloxacin hydrochloride by MgAl‐LDOs were assessed. The results show that: MgAl‐LDHs and MgAl‐LDOs are both mesoporous adsorbent materials. After MgAl‐LDHs were calcined at 400°C, their layered structure began to collapse partially. At the same time, their specific surface area, pore volume, and average pore diameter increased from 123.593 m2/g, 0.666 cm3/g, and 21.54 nm to 185.908 m2/g, 1.414 cm3/g, and 30.42 nm, respectively. The ability of MgAl‐LDOs to remove ciprofloxacin hydrochloride in water is much greater than that of MgAl‐LDHs. The research has shown that when the concentration of ciprofloxacin hydrochloride solution is 10 mg/L, at a pH of 5, and a temperature of 25°C, the equilibrium adsorption capacity can reach 22.69 mg/g in 420 min. The results of the quasi‐first‐order kinetic model and the quasi‐second‐order kinetic model show that the parameter R2 of MgAl‐LDOs adsorption of ciprofloxacin hydrochloride exceeds 0.94. The fitting parameters qe = 22.96 mg/g (10 mg/L) and qe = 107.02 mg/g (50 mg/L) in the quasi‐first‐order kinetic model, and the fitting parameters qe = 25.02 mg/g (10 mg/L) and qe = 112.72 mg/g (50 mg/L) in the quasi‐second‐order kinetic model are practically consistent with the measured equilibrium adsorption capacity.

Degradation of organic dye wastewater by H2O2-enhanced aluminum carbon micro-electrolysis.

In this research, the treatment of methylene blue (MB) dye wastewater by a novel system that combines H2O2 with an aluminum-carbon micro-electrolysis (ACE) was explored. The effects of the H2O2 amount, initial pH, aluminum to carbon ratio, total aluminum-carbon mass, dye concentration, and reaction temperature on degradation of MB were investigated. The findings revealed that under the following conditions: H2O2 34.0 mg/L, initial pH of 3.0, aluminum-to-carbon ratio of 2:1, total aluminum-carbon mass of 2.0 g/L, MB concentration of 20 mg/L, and 20 °C, the degradation rate of MB could reach 99.3% after 180 min, which is 18.4% more compared with ACE at the same conditions without H2O2. Through the quenching experiments, it was proved that the efficient free radicals produced during degradation are •OH and •O2-. Finally, a possible mechanism of H2O2 enhanced aluminum carbon micro-electrolysis (HP-ACE) for MB degradation was discussed.

Fracture characterization of a bi‐material bonded aluminum/CFRP joints under mixed‐mode I + II loading

AbstractFracture characterization under mixed‐mode I + II loading of bi‐material bonded joints with aluminum–carbon fiber reinforced polymer (AL‐CFRP) adherends was analyzed in this work. Five different and quite simple fracture tests were employed aiming to cover properly the complete mixed‐mode I + II range and identifying a representative energy‐based fracture criterion. A mode partitioning method lying on cohesive zone analysis was implemented, enabling the identification of strain energy mode I and mode II components for each type of test, which is relevant regarding the estimation of the energy‐based criterion defining the fracture envelope of these bi‐material joints.

Effect of Solution Temperatures on Electrochemical Behavior of Aluminum Alloys and Carbon Steel in 20 Mass％ NaCl Solutions

Effect of Solution Temperatures on Electrochemical Behavior of Aluminum Alloys and Carbon Steel in 20 Mass％ NaCl Solutions

Synthesis of Al-Al2O3-CNF Composite by Cold Spray Method: Powder Preparation and Synthesized Objects Characterization.

This paper is devoted to studying the composite material of the aluminum–alumina–carbon nanofiber (CNF) system. The paper considers in detail the process of preparation of the specified composite by ball milling, as well as the process of synthesis of a solid object (coating) by the cold spray method. The synthesized objects were studied using optical and electron microscopy, and the hardness of objects of various compositions was measured. The processes of interaction of composite particles are discussed in detail. The influence of CNF on the distribution of particles in a solid object and on the hardness of objects has been considered and discussed.