Addition Of Aluminum Research Articles

Thermodynamic modeling of the structure of alkali aluminophosphate glasses and their ionic conductivity

AbstractThis study presents the structural and ionic conductivity thermodynamic modeling for glasses with compositions in the system 50M2O‐xAl2O3‐(50 − x)P2O5, with M = Li or K. The Shakhmatkin and Vedishcheva thermodynamic model (SVTDM), or associated solutions model, has been previously used in successfully predicting the structure of simple binary phosphate glasses and it has now been employed with the aim to discerning the model's capability to predict the structural changes induced in the phosphate network by the addition of alumina. The results have been furthermore validated through their comparison with literature experimental data on the structural characterization of the glasses by 31P NMR measurements as well as on ionic conductivity determined by impedance spectroscopy. Although this methodology demonstrates good agreement with experimental data on the structure of aluminophosphate glasses, some disparities persist, potentially arising from experimental uncertainties. However, SVTDM faces limitations, including the need for comprehensive knowledge of stable phases and their formation energies. Predictions of ionic conductivity, though promising, exhibit deviations from experimental values, attributed to factors such as the influence of the chemical environment on dielectric properties. To enhance accuracy in conductivity prediction, a deeper understanding of additional variables such as dielectric constant and attempt frequency is imperative.

Influence of alumina on the performance of Ag/ZnO based catalysts for carbon dioxide hydrogenation

We study silver-zinc oxide type catalysts with and without the addition of alumina and perform structural analysis and activity tests for the hydrogenation of carbon dioxide. Adding alumina has a dispersing effect on the zinc oxide without structurally altering the silver phase. An alumina-surface enriched ZnO/Al2O3 phase is observed with an increased surface reducibility. Ag/ZnO has a high selectivity towards carbon monoxide (63 ± 12 %) and methane (24 ± 3 %) and low selectivity towards methanol (13 ± 0.5 %). Operando infrared (SSITKA-FTIR) and mass spectrometric product detection indicate methane formation via an adsorbed carbon monoxide (COads) intermediate. The selectivity changes gradually with increasing alumina content, up to 80 ± 3 % toward methanol, and 20 ± 4 % carbon monoxide without methane detection, combined with a tripling of the space time yield to 0.65 ± 0.02mmolMeOH*gcat-1*h−1 at 250 °C and 30 bar. Kinetic analysis suggests that the selectivity change originates from hindering the CO-pathway, while the formate pathway leading to methanol remains active.

Effect of Alumina as Reinforcement on the Mechanical and Physical Properties of Recycled AA6061 Aluminium

The utilisation of reinforcement materials in aluminium metal matrix composites is widely used in the manufacturing sector due to their lightweight nature, excellent strength-to-weight ratio, enhanced fracture toughness, and improved mechanical properties. The purpose of this study is to investigate the effect of reinforcing alumina in recycled AA6061 aluminium on the properties of the resulting aluminium matrix composite. Various compositions of recycled AA6061 aluminium reinforced with alumina were prepared and analysed using the cold compaction method. The results show that the addition of alumina composition increases the hardness properties of the composite by up to 5 wt.% at 32.91 Hv compared to the unreinforced sample at 30.63 Hv, but the hardness decreases as the alumina mass composition increases. According to the analysis of physical properties, in comparison to the unreinforced sample, the density decreases with increasing mass composition of alumina up to 10 wt.%, which is from 2.4636 g/cm3 to 2.3014 g/cm3, respectively. In relation to the microstructure of the samples, the addition of alumina results in irregular shapes with larger pores. An increasing in the mass composition of alumina results in increased porosity and water absorption.

Value Extraction from Ferrochrome Slag: A Thermochemical Equilibrium Calculation and Experimental Approach

The valorization of slag from the production of high-carbon ferrochrome is a challenge for ferrochrome producers. The recycling of high-carbon ferrochrome slag was explored through the smelting route to recover Fe–Si–Al–Cr alloys and reengineer the residual slag for alumina-enriched refractory material. In this research, the focus was to reduce the SiO2% and enrichment of Al2O3% in the final slag and recover the metallic value in the form of a complex alloy containing Fe, Si, Cr and Al. The manuscript consists of a thermochemical simulation of the smelting of FeCr slag followed by smelting experiments to optimize the process parameters such as temperature and the addition of coke, cast iron and alumina. An experimental investigation revealed that the maximum recovery of Si (57.4% recovery), Al in the alloy (20.56% recovery) and Al2O3 (85.78% recovery) in the slag was achieved at a charge mix consisting of 1000 g of FeCr slag, 300 g of alumina, 200 g of cast iron and 300 g of coke. The present study also demonstrated the usefulness of prior thermochemical calculations for smelting metallurgical wastes such as slag from high-carbon ferrochrome production for value creation and reutilization purposes.

Porosity and pore morphology characteristics of zirconia-alumina bioceramics

AbstractManufacturing ceramic green structures using starch consolidation casting is an established process that is simple, non-hazard, and low-cost. In this study, starch consolidation casting is used to prepare ceramics based on submicron monoclinic zirconia with additions of alumina and magnesia. Scanning electron microscopy results indicate that the size of pores decreased and the morphological irregularity increased when the tapioca starch content increased. The sample with 30 wt.% tapioca starch in a 55 wt.% slurry concentration had the highest estimated apparent porosity (around 56%), whereas the sample with 10 wt.% in a 68 wt.% suspension concentration had the lowest (about 35%).

Compressive strength of nano concrete materials under elevated temperatures using machine learning

In this study, four Artificial intelligence (AI) - based machine learning models were developed to estimate the Residual compressive strength (RCS) value of concrete supported with nano additives of Nanocarbon tubes (NCTs) and Nano alumina (NAl), after exposure to elevated temperatures ranging from 200 to 800 degrees. These models were developed via adapting meta- heuristic models including the Water cycle algorithm (WCA), Genetic algorithm (GA), and classical AI models of Artificial neural networks (ANNs), Fuzzy logic models (FLM), in addition to the statistical method of Multiple linear regression (MLR). 156 post heating experimental results available as a literature data (represents four input parameters of temperature change, heat exposure duration, nanomaterial type, and replacement proportion) are used to achieve the study’s objective. Results of the developed models demonstrated that ANN and FLM have strong potential in predicting RCS. However, it is often infeasible to generate practical equations that relate input and output variables from these models. Upon analysing the results of the WCA and GA, it was found that WCA yielded the most accurate predictions based on all performance indicators. Furthermore, RCS prediction equations with superior accuracy were derived utilizing the meta-heuristic AI models of WCA and GA, with Mean absolute errors (MAEs) of 3.09 kg/cm² and 3.53 kg/cm² for the training, 1.91 kg/cm² and 2.72 kg/cm² for the validation, and 1.91 kg/cm² and 2.72 kg/cm² for the testing data sets, respectively. Additionally, sensitivity analysis via neural networks weights and SHAP investigation were performed to reveals the impact and relationship of the input variables with the output variables. Both techniques reveal that temperature degree and time of exposure had the highest positive impact on RCS value, followed by NAl and NCTs, in order.

Chemical durability of optical temperature sensors made of tellurite glass: Effect of the alumina concentration

Tellurite glass is an amorphous material commonly doped with rare earth ions for the development of optical temperature sensors. Considering the intrinsic properties of glasses, it is expected that these sensors could be used in acidic environments and withstand temperature changes. However, this has not been fully demonstrated since most of the literature is limited to demonstrate the sensor operation under normal conditions. Additionally, there is a lack of information regarding the chemical durability of these glasses and methods to improve it. In this work, a special tellurite glass composition was proposed for the development of optical temperature sensor. The effect of the alumina concentration on the structure, chemical durability and emission properties of the glasses was evaluated. Chemical durability was assessed by monitoring the weight loss of glass samples after immersion in hydrochloric acid solutions at room temperature, vegetable oil or air at 150 °C. The results indicate that the addition of alumina increases the chemical durability of the glass and improves its emission properties. It was found that the average temperature estimated by the optical sensor had a relative error of 1.3 % due to the degradation of the glass caused by remaining immersed in a 1 N HCl solution for 60 days.

Characterisation and properties of Nanohybrid Dental Composite (NhDC) reinforced with zirconia and alumina

A trial nanohybrid dental composite (NHDC) was developed using silica extracted from biowaste rice. Aim: This study aims to test the effect of mixture of the silica and other filler which is zirconia and alumina, focusing on the characterization and their properties. Nano-silica obtained from rice husk was used as NHDC filler. Methods: Nanosilica white powder, derived from rice husk, was used. There were three groups: Group I, Zr (2%) and Al (3%); group II, Zr (3%) and Al (2%); and group III, Zr (3%). The distribution of filler particles and the chemical structure of filler particles were determined by FESEM images and FTIR test. Then, testing on Vickers hardness (VHN) and fracture strength (FS) of the samples was performed. Results: The distribution of filler particles showed a uniform distribution, and each peak element of the fillers was shown in the FTIR spectrum images. There was significantly increased on VHN and FS after addition of zirconia and alumina. Conclusion: This study concluded that zirconia and alumina strengthen the NHDC properties with addition of zirconia and alumina filler.

The effect of aluminum addition on plasma nitriding for 42CrMo steel

In order to enhance the efficiency and performances of nitriding layer, aluminum was primarily introduced in the furnace during plasma nitriding by adding some FeAl around the samples. The results show that the process efficiency is dramatically enhanced more than 5 times comparing with traditional plasma nitriding (PN), with the effective hardening layer increasing from 224 μm to 1246 μm at 520 ℃/4h. Meanwhile, ultra-high surface hardness and excellent wear behaviors are obtained by Al-PN due to the formation of dispersed strengthening phases of AlN and FexAl in the nitriding layer, with the surface hardness increasing from 755 HV0.025 to 1251 HV0.025, and the wear rate decreased by a factor of approximately 2.

AUBERT & DUVAL PER72

Abstract Aubert and Duval PER72 (NiCr18Co15TiMoAI alloy) is a precipitation hardening, nickel-base superalloy. The alloy is solid solution strengthened by additions of chromium, cobalt, molybdenum, and tungsten, while additions of titanium and aluminum provide precipitation strengthening. Aubert & Duval PER72 combines high strength with metallurgical stability as demonstrated by excellent impact strength retention after long exposures at elevated temperatures. It also exhibits good oxidation resistance, as well as excellent resistance to sulfide corrosion. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on low temperature performance, high temperature performance, and corrosion resistance as well as forming and heat treating. Filing Code: Ni-787. Producer or source: Aubert & Duval S.A. (a member of the Eramet Group).

Manufacturing of Ni-Co-Fe-Cr-Al-Ti High-Entropy Alloy Using Directed Energy Deposition and Evaluation of Its Microstructure, Tensile Strength, and Microhardness.

High-entropy alloys (HEAs) have drawn significant attention due to their unique design and superior mechanical properties. Comprising 5-35 at% of five or more elements with similar atomic radii, HEAs exhibit high configurational entropy, resulting in single-phase solid solutions rather than intermetallic compounds. Additive manufacturing (AM), particularly direct energy deposition (DED), is effective for producing HEAs due to its rapid cooling rates, which ensure uniform microstructures and minimize defects. These alloys typically form face-centered cubic (FCC) or body-centered cubic (BCC) structures, contributing to their exceptional strength, hardness, and mechanical performance across various temperatures. However, FCC-structured HEAs often have low yield strengths, posing a challenge for structural applications. In this study, a Ni-Co-Fe-Cr-Al-Ti HEA was manufactured using the DED method. This study proposes that the addition of aluminum and titanium creates a γ + γ' phase structure within a multicomponent FCC-HEA matrix, enhancing the thermal stability and coarsening the resistance and strength. The γ' phase with an ordered FCC structure significantly improves the mechanical properties. Analysis confirmed the presence of the γ + γ' structure and demonstrated the alloy's high tensile strength and microhardness. This approach underscores the potential of AM techniques in advancing HEA production for high-performance applications.

Transformation of Lampung Natural Zeolite into Zeolite-A by Aluminium Addition and Application as Catalyst for Biomass Pyrolysis

Transformation of Lampung Natural Zeolite into Zeolite-A by Aluminium Addition and Application as Catalyst for Biomass Pyrolysis

Study of Aging Characteristics for Metalized HTPB Based Composite Solid Propellants Stored in Ambient Conditions

The aging of any propellant is defined as the change in the physical, chemical, and performance parameters of solid rocket propellants. The propellant’s service life and aging properties are important parameters of the study, especially for missiles and other defense applications. Hydroxyl-terminated polybutadiene (HTPB) based composite solid propellants with ammonium perchlorate (AP) are the most prominently used propellants in the operations of solid rocket motors in the defense and space sectors. Thus, studying this composite solid propellant is of essential when determining ambient service life. Performance parameters studied in this research are burn rate under high-pressure conditions in Crawford bomb setup, Thermogravimetric Analysis, and Fourier Transform Infrared Spectroscopy (FTIR). SEM and X-ray diffraction (XRD) analysis of the aged sample were also conducted to ascertain the chemical composition and morphological changes in the samples. Naturally aged propellant strands manufactured in different years have been compared with freshly prepared ones to establish a trend for deriving conclusions. The results from different analysis techniques, FTIR, XRD, and FESEM, depicted that oxidation of metals happens while aging of propellant due to atmospheric moisture, and the metal oxides prominently affect the propellant chemical composition and decomposition process of the propellant samples. The ballistic properties of the aluminium added samples showed an increment in burn rate. In contrast, the bimetal addition of aluminium and magnesium combined as an additive decreased the ballistic burn rate.

The oxide films formed under the low oxygen pressure in a particular system containing competing chromium and aluminium

AbstractIn this paper, pre‐oxidation treatment was carried out at 950 °C under oxygen pressure of 10−16 atm for nickel‐10 % chromium‐x % aluminium‐1 % silicon‐0.5 % yttrium(x=0 wt.–%, 1 wt.–%, 3 wt.–%, 5 wt.–%) alloys. Morphology and structure of oxide layers on the alloys after pre‐oxidation were analyzed by scanning electron microscopy and electron discharge spectroscopy. The results showed that a chromium oxide film was formed on the surface of the alloy without aluminium addition, while the oxide layer on the surface of the alloy with aluminium addition gradually transformed into M2O3 (M=aluminium and chromium) oxide film. The oxidation behavior was analyzed by means of chemical thermodynamics, and it was seen that because the interaction coefficient,εijof aluminium and chromium is a positive value, the increase of aluminium addition will strengthen the interaction and increase the diffusion coefficient,Diof aluminium and chromium. The diffusion of chromium and aluminium in each other therefore promotes their interaction, which is beneficial to the formation of the outer oxide film. Thus, with the increase of aluminium addition, the thickness of the outer oxide film gradually increased, and the aluminium content in M2O3 (M=aluminium and chromium) increased significantly, and with 5 % aluminium added, the aluminium oxide of the outer oxide film became the main body.

(Alumina and graphene)/ PLA nanocomposites manufactured by digital light processing 3D printer

In this study, the variant effects of alumina and graphene reinforcing nanoparticle percentages on the tensile and wear properties of the nanocomposites, produced using digital light processing (DLP), were determined by employing SEM images of fracture and worn surfaces to introduce a hybrid (alumina + graphene)/PLA nanocomposite with desirable wear and mechanical properties. With the addition of alumina up to 2 wt%, the tensile strength was initially decreased exhibiting a rapid brittle fracture over the flat fracture surface. However, with a continued increase in the amount of reinforcing particles, the tensile strength eventually increased by 16% compared to the pure resin sample at 8 wt% of alumina while changing the fracture mode with plenty of cleavages accompanied by crack deflections. The specific wear rate in the 8 wt% alumina sample decreased by almost 62% compared to the pure resin sample. Graphene caused a significant drop in tensile strength due to the generation of cavities and porosities around the graphene agglomerates, but it greatly improved the wear properties, with the specific wear rate decreasing by almost 77% at just 1 wt%. Then hybrid nanocomposites of alumina and graphene reinforcements were produced with the aim of optimal tensile and wear properties. The 0.5% graphene +3.5% alumina improved the wear resistance and provided moderate tensile properties; however, the 1% graphene +3% alumina could not increase the wear resistance due to the weakening of graphene plates sticking to the polymer substrate.

Impact of Aluminium and Titanium Additives on Ignition and Combustion in Boron-Loaded Gelled Jet A-1 Fuel

ABSTRACT A high-energy metal has been identified as a possible supplementary energy source for liquid fuel, which can be used to fuel volume-limited propulsive devices. However, the stability of metal particles in liquid fuel is a significant disadvantage, which can be overcome by suspending the particles in the gel fuel network. Boron’s (B) high energy density makes it a potential choice as fuel or energetic fuel additive for propulsion systems. However, the combustion of boron particles is challenging due to a native oxide layer on the boron particle surface that acts as an inhibitor. The influences of aluminum and titanium addition into the gel fuel containing boron particles have been investigated in the present study to understand whether Al or Ti positively enhances the ignition and combustion of boron particles. A droplet combustion study was conducted for gel fuel samples containing boron, boron-aluminum, and boron-titanium combinations. The key analyses include the feature of droplet diameter regression, the effect of Al/Ti additive on the ignition delay of boron particles through spectroscopic analysis, combustion of boron particles through chemiluminescence measurement of intermediate species of boron combustion (BO2) and flame imaging, and analysis of combustion residues. The obtained results and corresponding analyses suggest that the addition of Al particles improves the ignition of boron. In contrast, Ti particles significantly enhance the combustion of boron particles loaded in gel fuel.

Hot pressing of SiC additivated with Al2O3 and Y2O3

This work investigated the sintering of silicon carbide (SiC) with alumina (Al2O3) and yttria (Y2O3) additives by hot pressing. Mixtures of SiC with 1% and 5% Al2O3 and Y2O3 were used, pressed at 1800 °C and 1850 °C, resulting in specimens that were characterized in terms of density, microstructure, Vickers hardness and fracture toughness. The addition of 5% oxide additives provided greater densification and better mechanical properties. The temperature of 1800 °C proved to be the most effective for sintering due to the microstructure presented. The analysis revealed a homogeneous distribution of additives and grains, concluding that the 5% additive is considerably superior for increasing the densification and mechanical strength of SiC.

FLAx‐REinforced Aluminum (FLARE): A Bio‐Based Fiber Metal Laminate Alternative Combining Impact Resistance and Vibration Damping

Fiber metal laminates (FMLs) have mainly been used in aerospace applications with synthetic fibers. To improve their environmental credentials and address issues regarding the end‐of‐life of these materials, a shift to FMLs based on natural fibers can be a promising course of action. However, regarding them as conventional FMLs overlook some of the unique benefits of natural fibers. Therefore, this study pioneers the examination of FLAx‐REinforced aluminum (FLARE) for its combined impact resistance and vibration damping. Dynamic mechanical analysis and vibration beam tests demonstrate that the metallic layer predominantly influences the damping behavior of FLARE. The loss factor notably decreases with aluminum addition (by 80% compared to the flax composite), approximated via an inverse mixture rule. Low‐velocity impact tests highlight the role of aluminum layers in energy absorption and the composite strength as a critical factor in impact resistance. FLARE exhibits 25% less specific energy absorption compared to its glass fiber counterpart. A quasi‐static analytical model suggests the potential of FLARE for practical applications. With its balance of properties and considering its potential advantages at end‐of‐life, allowing recycling of aluminum, and its expected lower carbon footprint, FLARE renders potential beyond the aerospace sector, e.g., in other forms of transportation.

Oxidation Behavior of MgO‐C Refractories Containing Metallic Aluminum, Calcium Magnesium Aluminate Aggregates, and Carbores P

The current investigation delves into the oxidation resistance of magnesia‐carbon‐bonded (MgO‐C) refractory enhanced with calcium magnesium aluminate (CMA) cement, metallic aluminum, and Carbores P across a broad temperature spectrum from 800 to 1600 °C. The results demonstrate that the modification with CMA up to a temperature threshold of 1200 °C does not compromise the material's inherent oxidation resistance. However, above this temperature, a decrement in oxidation resistance is observed. The impact of grain size variation in CMA on the oxidation resistance of MgO‐C refractories is notable, and the finer grains show a superior performance. MgO‐C sample with Carbores P has excellent oxidation resistance up to 1000 °C, while above 1200 °C, its oxidation resistance strongly deteriorates. The metallic aluminum addition exhibits a remarkable oxidation resistance throughout the evaluated temperature range, indicated by a slight oxidation.

Compositional effects in potassium metakaolin geopolymers containing alumina and glass frit

Geopolymers represent a distinct class of materials characterised by their X-ray amorphous nature and nanoporous, nanoparticulate structure. Geopolymers can be conveniently mixed, poured, and cured under ambient conditions. This makes this class of materials an interesting alternative to ordinary Portland cement for structural processes. Additionally, the addition of alumina can improve mechanical properties, while the addition of glass can form an impermeable glaze which could be useful for molten salt containment. Therefore, in this investigation, potassium metakaolin-based geopolymer composites with varying proportions of glass particles and alumina platelets were fabricated, cured, heat-treated, and analyzed to study the effects of composition on material properties. Various attributes including rheological properties, densities, mass loss, shrinkage, and porosities were compared. It was observed that certain compositions exhibited high viscosities, making high shear mixing challenging, while also displaying significant permeability that would hinder their ability to contain liquids without leakage. Additionally, certain samples showed reduced densities, suggesting potentially weaker mechanical properties; however, the investigation did not include a direct assessment of mechanical properties. The most promising candidates for containing liquids at high temperature contained 50 wt% KGP, 25 or 35 wt% glass powder, and 25 or 15 wt% alumina platelets, respectively. ASH-G slurries required a minimum of 65 vol% KGP to produce a homogenous material compatible with additive manufacturing. The minimum amount of glass phase to form surface glazes was 16 vol%. Only samples containing more glass phase than alumina phase produced glazed composites.