Pure Aluminum Powder Research Articles

Pyrometallurgical processing of manganese ore

Manganese ore contains valuable oxides, such as manganese oxide (MnO2/Mn2O3/Mn3O4), iron oxide (Fe2O3) and silica (SiO2). In the present study, an attempt has been made to separate these oxides through pyrometallurgical processing routes for the extraction of ferromanganese and silicomanganese. Lean manganese ores were subjected to ball milling followed by carbothermic reduction at a temperature of 1200 °C for 2 h. The reduced ores were then subjected to wet magnetic separation to obtain the magnetic constituents in the reduced ores. It was observed that it is not possible to remove the silica content from the ore. It appeared that the reduced sample had oxides of iron, silicon and manganese after its wet magnetic separation. The magnetic constituents were subjected to metallothermic reduction through pure aluminium powders to recover valuable metals/alloys.

Improvement of wear-resistant and thermal conductivity of aluminum matrix composite reinforced AL2O3/SiCw/Mg powder

Technological progress demands the development of materials that have special characteristics such as high strength, stiffness, light weight, and good thermal conductivity at a low price. The development of hybrid metal matrix composites is the most important field in advanced materials science engineering. This research determines about aluminum matrix composites (AMC) reinforced with alumina (Al2O3), Silicon carbide whisker (SiCw), and magnesium (Mg) addition. The matrix is made of 90 % pure aluminum powder, and commercially available reinforcing materials include Al2O3, SiCw, and Mg. Objectives include variation of reinforcement fraction and matrix, sintering holding temperature and time. The selection of the sample making process using powder technology followed by the sintering process at different temperatures namely 350, 450 and 550 °C with variations in holding time of 1, 2 and 3 hours. The purpose of this study was to determine the effect of variations in the fraction of reinforcement and sintering treatment on the properties of wear resistance, hardness and thermal conductivity of aluminum matrix composites. The results showed that the composition ratio of reinforcement to aluminum in sintering treatment significantly affected the mechanical properties. The wear resistance of the material shows excellent performance, namely wear resistance of 0.000065 gr/s, hardness of 45.234 VHN and thermal conductivity of 184.855 Watt/m °C, at a reinforcement composition combination of 10 %AL2O3, 10 %SiCw and 20 %Mg and a sintering temperature of 550 °C. This indicates that the Aluminum matrix composite reinforced with Al2O3/(SiCw/Mg) is able to support the friction load due to its low wear rate, good hardness, and good thermal conductivity. This material is very suitable to be used as tribology material, brake element, especially brake drum

Microstructure and oxidation of a Ni–Al based intermetallic coating formation on a Monel-400 alloy

Abstract The purpose of this work was to examine how the microstructure and oxidation characteristics of Monel 400 Alloy were affected by the low-temperature aluminizing method. Monel 400 alloy was subjected to a low-temperature aluminizing procedure for 2 and 4 h at 600, 650, and 700 °C. Pure aluminum powder was used as the source of aluminum deposition to prepare the packs for the process. The activator and inert filler utilized were ammonium chloride (NH4Cl) and Al2O3 powder, respectively. The coating surfaces were characterized using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), as well as X-ray diffraction (XRD) analysis. It was discovered that the through-thickness variance in the layer microstructure varied between 4 and 30 µm, and that it increased with greater process temperatures and times. The coating layer hardness grew to 800 HV after the deposition process, whereas the matrix hardness remained at 200 HVN. Furthermore, the sample that was coated at 600 °C for 4 h was exposed to oxidation at 750–800 and 850 °C. It was found that the oxidation kinetics were 176 kJ/mol.

Effect of hybrid ratio and sintering temperature on hardness properties of hybrid AMCs

The present research work is aimed toward fabrication of hybrid Aluminium matrix composites (AMCs) of different hybrid ratios of Alumina (Al2O3) and Silicon Carbide (SiC) followed by investigation of their microstructure and hardness properties. Hybrid AMCs were fabricated through powder metallurgy process by adding 5 wt% and 10 wt% mixture of Al2O3 and SiC reinforcements of various hybrid ratios (0:1, 1:3, 1:2, 1:1, 3:1, 2:1 and 1:0) with the pure Aluminium powder. The mixture powder were properly mixed by ball milling arrangements for 6 h. The mixture powder were preheated at 500 °C for 2 h in a high temperature programmable tube furnace followed by immediate compaction under a closed die at 1500 psi pressure through automatic hydraulic press. The compacted specimens were then sintered at 350 °C, 500 °C and 650 °C for 2 h in the same furnace. Hardness test of the fabricated hybrid AMCs were carried out by Vickers Micro-hardness testers and hardness values were measured by the integrated software. The hardness properties of hybrid AMCs also were compared with the hardness properties of pure Aluminium specimens fabricated through the same process route and process parameters. It is interestingly observed that hardness of hybrid AMC is more when pure Aluminium powder is reinforced with only SiC of same wt.% for both the cases (5 wt% and 10 wt% reinforce AMCs) and it decreases with decrease of weight fraction of SiC and simultaneously increase of weight fraction of Al2O3 keeping total weight fraction of mixture as constant.

Microstructure and tribological properties of aluminum matrix composites reinforced with ZnO–hBN nanocomposite particles

Abstract In this study, pure and hBN-doped ZnO nanoparticles were synthesized by sol–gel method. ZnO–hBN nanoparticles were mixed with pure aluminum powders and samples were prepared using powder metallurgy processing parameters. It was observed that Al, ZnO, and hBN nanocomposite particles formed homogeneously. With the addition of ZnO–hBN, significant changes occurred in hardness, wear, and friction coefficient values compared to pure Al samples. The highest hardness value in the samples is mesh. It was obtained as 105 HB in 10 wt.% hBN added sample. In the wear tests, it is seen that the wear resistance is seven times higher in the 1 wt.% hBN added sample compared to the pure Al sample, while the friction coefficient decreases with the increase of the hBN additive.

Tribological and Structural Effects of Titanium Carbide and Hexagonal Boron Nitride Reinforcement on Aluminum Matrix Hybrid Composites

This research involves the synthesis of a hybrid composite by adding titanium carbide (TiC) and hexagonal boron nitride (hBN) powders in certain weight ratios (2.5–5%) to pure aluminum (Al) powder. When previous studies were examined, it was seen that TiC and hBN powders were added separately to Al matrix powders; however, a hybrid composite was not produced as in this study. The obtained hybrid composites were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and X-ray diffraction (XRD) analysis. Microstructure, hardness and wear tests were carried out under 3 different loads (10 N, 20 N and 30 N) and dry conditions. Weight loss and coefficient of friction measurements were obtained for each hybrid composite during the wear tests. The TiC–hBN-reinforced specimen exhibited a significantly higher hardness value of 37.08% compared to the pure Al composite. It was also found that the synthesized Al–TiC–hBN hybrid composite exhibited a 59% reduction in the wear loss value for 10 N load, 30% for 20 N load and 60% for 30 N load compared to the pure Al sample. It is believed that the hybrid composites produced in this study have the ability to compete with Al matrix materials and exhibit the potential for longer durability and cost reduction in industries that use the production of aluminum parts.

Research on the energy properties and the storage stability of Al–Si–Li ternary alloy powders

To solve the problems of storage stability and compatibility of the Al–Li alloy powders, a series of Al–Si–Li alloy powders containing two-phase structure were prepared based on Al–Si–Li ternary phase diagram. The energy release, attenuation and compatibility of the Al–Si–Li alloy powders were studied by oxygen bomb calorimeter, XRD, SEM, TG-DSC and SIMS. As the content of the AlSiLi intermetallic compound phase increased, the measured mass combustion enthalpies increase before decreasing. When the proportion of the AlSiLi intermetallic compound phase is 20 wt.% (denoted as 20%-ASL), it has the maximum mass combustion enthalpy (31729 J⋅g−1) which is higher than the theoretical mass enthalpy of the pure aluminum powder (31000 J⋅g−1). The aging test of the 20%-ASL alloy powder show that its measured mass combustion enthalpy only decreased by 5.5 % (from 31739 J⋅g−1 to 29921 J⋅g−1), along with the thermal oxidation weight gain decreasing from 95.82 % to 80.04 %, while mass combustion enthalpy of the Al–Li alloy powder with the same Li content decreased by 17.5 % (from 30325 J⋅g−1 to 25031 J⋅g−1), and the weight gain decreased from 96.68 % to 41.05 %. This indicates that the AlSiLi phase effectively improves the oxidation resistance and storage stability of the Al–Li alloy powders. To explain this, surface Li distribution of the 20%-ASL alloy powder was analyzed by SIMS. The results show that the AlSiLi phase can immobilize Li inside the particles to reduce surface Li content from 2.920 × 106 to 1.439 × 106 and improve its oxidation resistance, thereby improving its storage stability and compatibility.

Effective chloride ion resistance of aluminum powder through interface electric field designing

Pure aluminium (Al) powder is widely used in aerospace fields as fuel while its corrosion mechanisms and anti-corrosion strategies are not thoroughly studied. Herein, corrosion mechanisms of Al nanoparticles are revealed by density functional theory (DFT) and experiments. Moreover, by utilizing the behaviour of ions moving in the electric field, an interfacial electric field is designed to endow spherical aluminium powder (sAl) with high anti-corrosion for chloride ions (Cl−). Because TiO2 presents lower electrostatic potential than Al2O3 which is on the surface of sAl, the prepared core@shell structural material (sAl@TiO2) holds an interfacial electric field and its direction is from TiO2 to Al2O3. The electric field repels the Cl− adsorption on the surface of sAl@TiO2, bringing about superior Cl− anti-corrosion.

Direct Writing of Reactive Inks Based on Electroless Nickel Deposition on Pure Aluminium Powders

Direct Writing of Reactive Inks Based on Electroless Nickel Deposition on Pure Aluminium Powders

Surface Fluorinated Metastable Aluminum Microspheres: Improved Ignition and Anti-Aging Properties of Aluminum Powder

ABSTRACT Incorporating fluorine-containing organic compounds onto the surface of aluminum powder in order to reduce the mass transfer distance and increase the heat transfer efficiency during the combustion of aluminum powder and fluoride is a difficult problem to solve due to the fact that aluminum powder contains almost no chemical functional groups. Herein, monodisperse Al@PVDF microspheres were prepared by a simple dry-spray method by directly combining Al powder and PVDF. The contents of PVDF and Al in Al@PVDF microspheres can be adjusted arbitrarily. PVDF can be tightly and uniformly bound on the surface of aluminum particles by characterization of Al@PVDF microspheres. Al@PVDF microspheres can improve the hydrophobic properties of aluminum powder and effectively inhibit the corrosion of water and strong alkaline solutions on aluminum. Al@PVDF microspheres exhibit greater hydrophobicity than aluminum powder and are capable of efficiently inhibiting the corrosion of aluminum by water and strong alkaline solutions. Additionally, the ignition and reaction performance of Al@PVDF microspheres under high temperature conditions are also studied in detail. Al@PVDF microspheres exhibit lower ignition temperature and higher reactivity than pure aluminum powder. Al@PVDF microspheres can also effectively suppress the combustion agglomeration of aluminum powders.

Effects of shear deformation on grain size and mechanical properties of the forged B4Cp/Al composite

Abstract To flake aluminum powder and strengthen the B4Cp/Al composite, pure aluminum powder is natural oxidized and ball milled. The effect of shear deformation on mechanical properties of the forged B4Cp/Al composite with flaked Al are studied. The results show that ball milling can flake the pure aluminum powder, reduce grain size of aluminum, and increase the volume fraction of Al2O3 on the surface of the flaked aluminum. The forging helps to refine the grain size of aluminum. The flow of aluminum matrix is helpful to the uniform distribution of the B4C particles. Shear deformation can refine grain size and also can break the Al2O3 layer, with the increment of strength, hardness, and relative density. After shear deformation, the ultimate tensile strength of the B4Cp/Al composite is 157.0 MPa.

Comparative Study on Combustion Behavior of Aluminum-Based Alloy Fuels and Aluminum Powder in Solid Propellants

In order to reduce the ignition temperature and improve the combustion efficiency of aluminum powder, three aluminum-based alloy fuels, Al–Mg, Al–Zn, and Al–Si–Mg, were prepared by the atomization method. The oxidation, ignition, and combustion performance of alloy fuels were investigated, and the results showed that, using pure aluminum powder as a reference, the weight gain of alloy fuels increased from 10% to 84%, the reaction activation energy decreased from 582 kJ·mol−1 to 208 kJ·mol−1, the alloy fuels containing Mg had good ignition response, and aluminum-based alloy fuels showed high calorific value and efficient combustion as a whole. In order to investigate the combustion behavior of alloy fuels in the solid propellant, tests were conducted on the mechanics, safety, process, and combustion properties of propellant according to the national standard, and the test results showed that, compared with the propellant made of aluminum powder with same quality, the propellant made of alloy has better mechanical properties, higher frictional sensitivity, lower electrostatic sensitivity, comparable process performance, and increased combustion calorific value and combustion speed. Engine test results confirmed that Al–Zn and Al–Si–Mg alloy fuels could effectively improve the specific impulse efficiency of the solid propellant and reduced the residual rate of the engine.

Influence of annealing on the structure and wear resistance of coatings produced by cold spraying of Al–SHS7574 powder mixture

In present work, the possibility of fabricating a composite cold-sprayed coatings consisting of partially amorphous alloy reinforcing particles and an aluminum matrix was studied for the first time. A mixture of pure aluminum and SHS7574 powders in a ratio of 50/50 wt% was deposited on aluminum alloy substrates, which ensured the formation of high-quality coating with a porosity of less than 1%. The ratio of SHS7574 alloy to aluminum in the as-sprayed samples was nearly the same as in the initial powder mixture which indicates a similar efficiency of component deposition. Composite coatings were annealed in a vacuum furnace at 540 °C and 600 °C. Microstructure and phase composition of as-sprayed and annealed coatings were examined with XRD, SEM and EDX mapping. Post annealing of the coatings promoted the formation of a reaction layers around the Fe-based alloy particles consisting of Fe2Al5, Fe4Al13, Fe23B5, and Fe5C2 phases. The effect of annealing on the mechanical properties of the Al–SHS7574 coatings was determined by measuring hardness, nanohardness and wear resistance according to ASTM G 133–05. The increase in the samples’ hardness after annealing was associated with the formation of a reaction layers and increase in its thickness with rising annealing temperature. The coating annealed at 600 °C demonstrated the highest hardness due to the formation of thick brittle reaction layers. The preservation of the aluminum matrix with the simultaneous formation of thin reaction layers after annealing at 540 °C reduced the wear rate of the coating despite the moderate hardness.

Combustion-supporting effect of boron powder on aluminum powder

Aluminum powder is a very important component in both explosives and propellants. Due to the formation of a dense oxide layer Al2O3 at the surface of aluminum, it is very difficult for aluminium powder to react completely, which is the biggest problem at present. For improving the completeness of the reaction of aluminum powder, six kinds of combustion accelerants, ferrocene, ammonium perchlorate, Fe2O3, fluororubber F246, perfluorosurfactant HX-12 and boron powder were selected to study their combustion-supporting effect on aluminum powder by differential scanning calorimetry (DSC) method. The research results show that the six reagents have certain combustion-supporting effects, but the combustion-supporting effect of boron powder is particularly significant. Two extra exothermic peaks appeared as adding small amount of boron powder to aluminum powder. When the content of boron powder is 10 wt % of aluminum powder, the total exothermic heat is more than twice than that of pure aluminum powder FLQT-4. In short, boron powder is a very promising combustion accelerant.

Slurry preparation for semi-solid metal direct writing by a novel approach of mixed powder remelting

Extrusion-based metal direct writing is a promising metal additive manufacturing technology due to its high efficiency and low cost. However, fabricating parts with high integrity and complex geometry remains challenging. The most critical factor is the unavailable of semi-solid slurries with uniform and nearly spherical solid particles, resulting in uncontrollable extrusion and printing. Currently, mixed powder remelting (MPR) is reported to preset the features of the solid phases, including volume fraction, morphology, and size distribution. Specifically, the semi-solid slurries of hypoeutectic AlSi alloys were obtained by preheating and shearing the mixed powder composed of eutectic AlSi alloy powder and pure aluminum powder. Their microstructural characteristics and rheological behavior were investigated, demonstrating the microstructure tailoring (controllable solid fraction and size distribution, high shape factor of about 0.9) and the reduced viscosity fluctuation by a factor of 7 compared with traditional processes. MPR shows unparalleled advantages for further engineering applications of metal direct writing.

Effect of Magnesium Dopant on the Grain Boundary Stability of Nanocrystalline Aluminum Powders during Cryomilling

In this investigation, pure aluminum (Al) powders were cryomilled with and without magnesium dopants to study (a) the effect of cryomilling time on the crystallite size and (b) the effect of magnesium dopant on Al to achieve grain boundary stability. The cryomilling process was carried out using liquid nitrogen for different durations. The characterization of the cryomilled powders was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to understand the particle morphology, crystallite size, and elemental composition. The results demonstrated that the size of the crystallites in both Al and Mg-doped Al powders reduces as the cryomilling duration increases. The results also indicated that the preferential segregation of Mg dopant at the grain boundaries of Al provides stability to the cryomilled powders at elevated temperatures. This article discusses the mechanism for the changes in crystallite size and the effect of the Mg dopant on the grain boundary stability in Al powders.

Utilization of coarse non-ferrous fraction of incineration bottom ash as aerating agent in autoclaved aerated concrete

Past studies by the authors have demonstrated the feasibility of utilizing municipal solid waste (MSW) incineration bottom ash (IBA) as an aerating agent to produce autoclaved aerated concrete (AAC). However, the gas generation potential of as-received IBA (General IBA) is significantly poorer than conventional aerating agents such as pure aluminum powder. The classification of IBA showed that coarse non-ferrous IBA fraction with particle size greater than 1.18 mm (CNF-IBA) contains a higher concentration of metallic aluminum. This study proposes specifically utilizing CNF- IBA fraction as an aerating agent to produce AAC. Two other AACs with pure Al powder and General IBA as aerating agents were investigated for systematic comparison. The aeration kinetics, fresh, and hardened properties were experimentally investigated. A novel approach is presented to study the influence of coordination between aeration extent and yield stress development on volume expansion capacity. The developed AAC with CNF-IBA exhibited the highest specific compressive strength. The leaching analysis showed that the usage of IBA as an aerating agent in AAC production is safe during the service life of AAC, and its demolished samples at the end of service time can be landfilled as inert material.

Non-coupled Finite Element Modelling of Electromagnetic Radial Compaction of Pure Aluminium Powder

Non-coupled Finite Element Modelling of Electromagnetic Radial Compaction of Pure Aluminium Powder

Durability of peat stabilized by RHA based geopolymer formed by adding pure alumina and bauxite powder

This study examines the effect of Nwd cycles on unconfined compressive strength (UCS), pH, electrical conductivity (EC), mass loss (ML) of treated sapric, fibric and hemic peat. The two types of rice husk ash (RHA) based geopolymers are formed by adding two different sources of extra aluminium as pure Al2O3, referred to as G1, and bauxite referred to as G2. For comparison, ordinary Portland cement was selected as a control sample. From the results, the UCS of geopolymer treated peats show more strength than cement treated peats because the hydrotalcite phases of geopolymer fill the voids more efficiently. However, the rate of decrement of UCS in both geopolymer treated peats is more than cement treated peats because the increased number of micropores in geopolymer treated peats. The field emission scanning electron microscope (FESEM) micrographs show dense and smooth cementitious products before Nwd cycles consistent with X-ray diffraction (XRD) results and show the existence of micropores after Nwd cycles for geopolymer treated peats. Fourier transform infrared spectroscopy (FTIR) confirms the results of XRD as it shows the adsorption bands of aluminosilicates, which form the basis of geopolymerization, and further confirms the existence of cavities and cracks in samples after Nwd cycles.

Machining performance of Nano SiC and graphite powder mixed aluminum matrix composites fabricated by powder metallurgy using EDM

Currently, aluminum MMCs are increasingly being used for different engineering applications due to their lot advantages. In this experiment, MMCs were machined using electrical discharge machining (EDM) to get high-performance results. Powder Metallurgy method was used to add different percentages of Graphite (3 %, 5 % & 7 %) and Silicon Carbide (5 %, 10 % & 15 %) Nano-powders to pure Aluminum powders. Different Compaction loads and Sintering temperatures were taken at 150, 200 & 250 KN, and 500, 550 & 600 °C respectively. The process parameters have been designed using the Taguchi L9 orthogonal array. With input parameters such as current (I), pulse on time (Ton), pulse off time (Toff), and voltage, the EDM technique was chosen for machining composite materials. The addition of silicon carbide particulates with aluminum metal matrix increases the Surface Roughness (Ra) and Hardness but decreases the Metal removal rate (MRR), and a suitable amount of graphite particulates with aluminum metal matrix increases MRR, SR, and Hardness also of the composite material. The Taguchi technique is used to assess the best P/M process parameter setting for a given signal-to-noise (S/N) ratio order.