Atomic scale study of the dehydration/structural transformation in micro and nanostructured brucite (Mg(OH)2) particles: Influence of the hydrothermal synthesis conditions

Micro and nanostructured brucite (Mg(OH₂)) particles synthesized by hydrothermal method from solutions with high content of hydrazine (0.14 M) and nitrate (0.24 g) were compared with samples obtained from low hydrazine content (0.0002 M) and nitrate (0.12 g). The samples were heated at 180 °C for 4 h, 6 h and 12 h. XRD, TEM-HRTEM, SAED and image analysis techniques were used for the morphological and structural characterization. The effect of electron beam irradiation on the brucite dehydration was observed in atomic resolution images at 300 kV. Hexagonal crystals show differences in crystallinity, strains and kinetic of reaction. High hydrazine/nitrate samples have slightly larger crystals with better crystallinity, showing a strong preferential orientation. Rietveld refinements show how unit cell parameters are bigger in samples obtained with higher hydrazine/nitrate content, confirming also the preferential orientation along the 0 0 0 1 plane. Differences in the dehydration process show the rapid formation of a porous surface, the amorphised cortex or the presence of highly oriented strains in samples prepared from higher hydrazine/nitrate content. Conversely, crystals slightly smaller with randomly scattered defect surfaces showing the Mg(OH)₂/MgO interphase in samples prepared with low hydrazine/nitrate content. Significant differences in the kinetic of reaction indicate how the dehydration process is faster in samples prepared with high hydrazine/nitrate content.     

Structural and functional properties of ZnO thin films grown on Si substrates by air assisted USP method from non-aqueous solutions at low-temperature

In this work, we deals with the processing and characterization of transparent conducting ZnO thin films on p-type Silicon substrates (1 0 0) by air assisted Ultrasonic Spray Pyrolysis (USP) method. The thin films from different Zn acetate precursor solution concentrations (0.1, 0.2, 0.3 and 0.4 M) were deposited at several temperatures (400, 450 and 500 °C) with thickness from ～100 to ～500 nm. The effects of precursor solution concentration, deposition time and temperature on the structural, morphological, optical, and electrical properties of ZnO films were studied by X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), UV–Vis-NIR spectroscopy, and Hall Effect techniques, respectively. It has been shown that on the ZnO film surface, the preferred orientation, the average crystallite size, the electrical resistivity and the RMS surface roughness depend on the substrate temperature. The grown films have showed a good adhesion and an excellent optical transmission of about 80–95% within the visible range (400–800 nm) and a direct band gap from 3.35 to 3.23 eV with the increase of the substrate temperature and the deposition time. All the PL spectra have exhibited a typical green-yellow emission band. Additionally photovoltaic (PV) activities of n-ZnO/p-Si heterostructures fabricated are investigated.     

Amorphization and nanocrystalline Nb3Al intermetallic formation during mechanical alloying and subsequent annealing

In this paper the formation as well as the stability of Nb₃Al intermetallic compounds from pure Nb and Al metallic powders through mechanical alloying (MA) and subsequent annealing were studied. According to this method, the mixture of powders with the proportion of Nb-25 at% Al were milled under an argon gas atmosphere in a high-energy planetary ball mill, at 7, 14, 27 and 41 h, to fabricate disordered nanocrystalline Nb₃Al. The solid solution phase transitions of MA powders before and after annealing were characterized using X-ray diffractometry (XRD). The microstructural analysis was performed using scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). The results show that in the early stages of milling, Nb(Al) solid solution was formed with a nanocrystalline structure that is transformed into the amorphous structure by further milling times. Amorphization would appear if the milling time was as long as 27 h. Partially ordered Nb₃Al intermetallic could be synthesized by annealing treatment at 850 °C for 7 h at lower milling times. The size of the crystallites after subsequent annealing was kept around 45 nm.     

Synthesis,characterization and photocatalytic properties of nanostructured ZnO particles obtained by low temperature air-assisted-USP

ZnO nanoparticles were synthesized in a horizontal three zones furnace at 500 °C using different zinc nitrate hexahydrate concentrations (0.01 M, 0.1 M, and 1.0 M) as a reactive precursor solution by air assisted Ultrasonic Spray Pyrolysis (USP) method. The physico-chemical, structural and functional properties of synthesized ZnO nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), Brunauer, Emmett and Teller (BET) method, UV–vis spectroscopy and photoluminescence (PL) measurements. Also, the photocatalytic activities of ZnO synthesized from different precursor concentrations were evaluated by removal rate of methyleneblue (MB) under UV irradiation (365 nm) at room temperature. SEM revealed two types of ZnO nanoparticles: a quasi-spherical, desert-rose like shape of the secondary particles, which does not change significantly with the increasing of precursor solution concentration as well as some content of the broken spheres. Increasing the precursor solution concentration leads to the increase in the average size of ZnO secondary particles from 248 ± 73 to 920 ± 190 nm, XRD reveals the similar tendency for the crystallite size which changes from 23 ± 4 to 55 ± 12 nm in the analyzed region. HRTEM implies the secondary particles are with hierarchical structure composed of primary nanosized subunits. The PL spectra imply a typical broad peak of wavelength centered in the visible region exhibiting the corresponding red-shift with the increase of solution concentration: 560, 583 and 586 nm for the 0.01, 0.1 and 1.0 M solution, respectively. The reported results showed the photocatalytic efficiency of ZnO nanoparticles was enhanced by increased precursor concentration.     

Synthesis of hydroxysodalite zeolite by alkali-activation of basalt powder rich in calc-plagioclase

Hydroxysodalite (H-SOD) microcrystalline particles were synthesized from basalt powder rich in calcic-plagioclase (anorthite) by alkali activation at 80 °C/24 h. Sodium hydroxide (NaOH) solution was used as alkaline activator. The reactivity of the natural solid precursor basalt was studied using differential scanning calorimetry (DSC), and a maximum reaction enthalpy of (?ΔH) of 170 J/g was obtained. The chemical, mineralogical, and textural properties were obtained by using X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and N₂-adsorption-desorption measurements. The synthesized material has a specific BET surface area of 20.5 m² g^?1 approximately 200 times higher than raw basalt material (0.1 m² g^?1). The compressive strength of basalt based H-SOD/sand composite samples cured at 80 °C for 24 h upon using different amounts of the activator (NaOH) was evaluated under dry and saturated conditions. The dry samples with NaOH/basalt mass ratio of 0.12 have reached a compressive strength of 57 MPa. Wet samples, on the other hand, showed a compressive strength of 25 MPa after seven days of soaking in water and four episodes of wetting and drying. The present work illustrates that crystalline H-SOD could be synthesized from cheap basalt powder precursor.     

Synthesis and characterization of superfine pure tetragonal nanocrystalline sulfated zirconia powder by a non-alkoxide sol–gel route

Nanocrystalline sulfated zirconia powder was prepared by a non-alkoxide sol–gel route using acidic condition (pH 1–2). The samples had superfine crystallites and pure tetragonal phase at 700 °C. Zr(acac)₄ was used as zirconium precursor due to a better retention of sulfate species and H₂SO₄ 0.5 M was used as sulfating agent. Fourier transform infrared (FT-IR) spectra have shown Zr–O–Zr and sulfate bonds. Crystal phase and crystallite size have been determined by X-ray Diffraction (XRD) analysis. Besides, the morphology of the samples has been investigated by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The optical properties of the samples have been analyzed using photoluminescence (PL) spectroscopy, too. All the analyses consistently have shown fairly uniform nanoparticles (calcined at 600 and 700 °C) with very small size and pure tetragonal phase with crystallite size between 5 and 10 nm.     

Vitis vinifera peel polyphenols stabilized gold nanoparticles induce cytotoxicity and apoptotic cell death in A431 skin cancer cell lines

Gold nanoparticles (AuNPs) are considered beneficial in the field of biomedicine and in the development of therapeutic nanomedicine products. In the present study, Vitis vinifera. L (grapes) peel polyphenols were utilized as reducing and stabilizing agents for the biosynthesis of gold nanoparticles, and their cytotoxicity and apoptotic effects were assessed. The synthesized gold nanoparticles were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD), Particle size distribution, Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. TEM analysis confirmed that the nanoparticles were spherical with ～20–40 nm in size. Particle size distribution revealed ～50 ± 5 nm nanoparticles and FTIR confirmed the presence of polyphenols capped onto the peel gold nanoparticles. The V. vinifera peel gold nanoparticles were studied for their antiproliferative activities and induction of apoptosis at the inhibitory concentration (IC₅₀) of 23.6 µM. A431 cell lines incubated with V. vinifera peel gold nanoparticles for 24 h exhibited cytotoxicity activity mediated by increased reactive oxygen species (ROS) production, apoptotic morphological changes and loss of membrane potential significantly (p < 0.01). Thus, the cytotoxicity of the gold nanoparticles could be attributed to the synergistic effects of the phenolic moieties of the V. vinifera peels and the efficiency of the bioconjugated gold nanoparticles causing apoptosis and secondary necrosis.     

Molten-salt synthesis of tetragonal micron-sized barium titanate from a peroxo-hydroxide precursor

Barium titanate (BaTiO₃) was produced from an barium-titanate-peroxo-hydroxide precursor material in NaCl-KCl and Na₂SO₄-K₂SO₄ salt mixtures or fluxes at temperatures up to 1080 °C via the molten-salt synthesis (MSS) method. Beside the different salt mixtures several other parameters were studied to determine the effect on the particle morphology. A relatively fast heating rate and a relatively high salt to precursor ratio resulted in a highly faceted morphology. The effect of the salt flux was clearly seen in the morphology of BaTiO₃ obtained by MSS at 1080 °C. Cube-shaped particles were observed for the chloride-flux-grown BaTiO₃ while hexagonal-shaped flat particles were observed for the sulfate-flux-grown BaTiO₃. BaTiO₃ particles produced in the chloride-flux were either {1 0 1} or {0 0 1} faceted. The hexagonal surface of the sulfate-flux-grown BaTiO₃ was {1 1 1} faceted.     

Preparation of hydroxypropyl methyl cellulose phthalate nanoparticles with mixed solvent using supercritical antisolvent process and its application in co-precipitation of insulin

To obtain hydroxypropyl methyl cellulose phthalate (HPMCP)/insulin nanospheres by supercritical antisolvent process, the formation of HPMCP nanoparticles was first investigated. The effects of ratio of the mixed solvent, pressure, temperature, concentration, flow rate of CO₂ and solution on forming HPMCP nanoparticles are discussed. It was found that different morphologies of HPMCP could be produced by varying the ratio of DMSO to acetone in the solvent. The operating parameters were optimized for making HPMCP nanoparticles. Formation of HPMCP/insulin nanospheres was further inspected. The nanospheres with the size ranging from 138 nm to 342 nm were obtained. The loading of insulin in the nanospheres ranged from 10.76% to 16.04% and the encapsulation efficiency reached 100%. The release of insulin is also discussed.     

Synthesis of dispersed PrBaCo0.9Cu0.1O5+δ cathode nanopowders with layered perovskite structure for intermediate temperature solid oxide fuel cells

PrBaCo_1.9Cu_0.1O_5+δ (PBCCO) nanopowders were synthesized by an EDTA-citrate complexing process using water and ethanol as solvents, and their structures and electrochemical properties were characterized. PBCCO precursor gels were highly oxidized at 450 °C, using either water (PBCCO-W) or ethanol (PBCCO-E) as the solvent. PBCCO powders calcined at 450 °C had a second phase, while those calcined at 850 °C for 4 h were obtained as single phase PBCCO with a layered perovskite structure in the P4mm space group. PBCCO-E primary particles were approximately 5–10 nm in size and were well-dispersed compared with those of the PBCCO-W powder. We hypothesized that the enhanced dispersibility of the PBCCO-E powder was caused by a decrease in bridging hydrogen bonds on the chelate surface, which prevents chelate agglomeration in sol state. It causes the larger specific surface area of PBCCO-E powders and thus a lower polarization resistance (R_p) than that of PBCCO-W powders at the measured temperature. The R_p value of PBCCO-E powder was 0.041 Ω cm² at 750 °C, which is about 1.5 times lower than that of PBCCO-W at the same temperature.     

Sol–gel derived Cr(III) and Cu(II)/γ-Al2O3 doped solids: Effect of the dopant precursor nature on the structural,textural and morphological properties

Powders of xerogel γ-Al₂O₃ doped with various concentrations of Cr³⁺ and Cu²⁺ (M/M + Al molar fraction = 0.75–10%) were prepared via a sol–gel method. Cr³⁺ and Cu²⁺ precursors (acetylacetonate, nitrate or chloride) were added to 0.12 M 2-propanol solution of aluminum tri-sec-butoxide (ASB) and hydrolysis was performed using a H₂O/ASB molar ratio of 4.7. The effect of the dopant precursor on structural, textural and morphological properties was studied. Employing acac precursors resulted in unique properties after calcination at 500 °C including high surface areas, as high as 455 m²/g, homogeneous mesopores, 3–12 nm, and amorphous powders (5–10 nm particles in diameter). On the other hand, the acac precursor enhanced the resistance to sintering mainly at higher metal loads (10%) and elevated temperature (800 °C). Nevertheless, the solids issued from nitrate and chloride precursors exhibited lower surface areas at high metal loads, and lower resistance to sintering.     

Solvothermal synthesis of Ag/ZnO micro/nanostructures with different precursors for advanced photocatalytic applications

Micro/nanostructured systems based on metallic oxide (ZnO) with noble metal (Ag) on the surface (Ag/ZnO) are synthesized by solvothermal method from zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O), zinc acetate dehydrate (Zn(CH₃COO)₂·2H₂O), zinc acetylacetonate hydrate (Zn(C₅H₇O₂)₂·xH₂O) and silver nitrate (Ag(NO₃)) as precursors. In these systems, polyvinylpyrrolidone (PVP) is used as surfactant for controlling particle morphology, size and dispersion. The obtained materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), UV–vis diffuse reflectance spectroscopy (DRS), N₂ gas adsorption–desorption (BET) and Raman spectroscopy (RS). By XRD results, all major peaks are indexed to the hexagonal wurtzite-type structure of the ZnO and samples with noble metal, extra diffraction peaks are detected which correspond to the face-centered-cubic (fcc) structure of the metallic Ag. Depending on used precursor, different morphologies have been obtained. Mainly, ZnO prims-like rods – NRs (with 0.8 ? aspect ratio ? 3.4) – have been observed. Quasi-spherical particles of metallic Ag (with diameters between 558 ± 111 μm and 22 ± 1 nm) have been detected on the ZnO surface. Photocatalytic results (all samples studied >30% MB degradation) verify the important effect of surfactant and the viability of synthesized Ag/ZnO micro/nanocomposites for environmental applications.     

A two-step method for synthesis of micron sized nanoporous silver powder and ZnO nanoparticles

Micron-sized nanoporous silver powder with pore size of ～100–160 nm and specific surface area of ～4.7–5.5 m²/g was synthesized from three mechanically alloyed Ag-Zn powders (composition: 25, 50 and 75 at.% Zn). Dealloying was carried out at free corrosion conditions in NaOH, HCl and AgNO₃ solutions. Both partial and complete dealloying were obtained by suitable choice of electrolyte and time of exposure. Zn in the solution after dealloying was recovered in the form of ZnO nanoparticles with particle size of 55.7 ± 18 nm. The effect of composition and electrolyte on the degree of dealloying was also studied.     

Relationship between dealloying conditions and coarsening behaviors of nanoporous copper fabricated by dealloying Cu-Ce metallic glasses

Monolithic nanoporous copper(NPC) with tunable ligament size(107–438 nm) was synthesized by dealloying a new Cu-Ce binary glassy precursor in dilute H_2SO_4 aqueous solution. The effects of the dealloying conditions on the morphologies of NPC were evaluated comprehensively. The results show that the ligaments of NPC can significantly coarsen with the increase of acid concentration, elevation of reaction temperature or prolongation of immersion time. These coarsening behaviors can be well described by a diffusion based growth kinetic model. Moreover, the surface diffusivity and activation energy for diffusion of Cu atoms were also estimated to investigate the formation mechanism of NPC, which is mainly governed by dissolution of Ce element in the glassy precursor coupled with nucleation and growth of Cu clusters via the precursor/solution interface. In the experiment of the degradation of methyl orange(MO) dye, the NPC fabricated by Cu-Ce metallic glasses exhibits superior sono-catalytic activity.     

Rapid hydrothermal synthesis of SrMo1−xWxO4 powders: Structure and luminescence characterization

Strontium molybdate, strontium tungstate particles and their solid solutions (SrMo_1?xW_xO₄) with 0 ? x ? 1.0, were synthesised by means of a hydrothermal process. Crystallisation of SrMo_1?xW_xO₄ particles took place rapidly using SrSO₄ as the Sr precursor under hydrothermal conditions involving stirring (130 rpm) at 150 or 200 °C for 2 h. Structural analyses of the powders were conducted by XRD with Rietveld refinement and FT-Raman spectroscopy, and the particle shape was observed by FE-SEM. Lattice parameter measurements indicated a linear dependence of both “a₀” and “c₀” in the scheelite structured SrMo_1?xW_xO₄ with a changing W content following Vegard’s law. These analyses also provided evidence of the structural variation localised in the tetrahedral site as a result of the simultaneous incorporation of MoO₄ and WO₄ in the solid solutions formed in the compositional range of 9 ? x ? 60 mol%. The SrMo_1?xW_xO₄ particles exhibited a predominantly euhedral shuttle-shaped morphology and particle sizes varying between 0.75 and 1.5 μm. The particle growth was affected by increasing the reaction temperature and the tungsten concentration. Photoluminescence analysis (PL) revealed a marked attenuation of the blue and green emissions preferentially for the powder containing 48.5 mol% of W, which makes it potentially useful for optoelectronic applications.     

A new scale for optimized cryogenic magnetocaloric effect in ErAl2@Al2O3 nanocapsules

The Er Al_2@Al_2O_3nanocapsules with Er Al_2core and Al_2O_3shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy.Transmission electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 nm.Magnetic investigation revealed the Curie temperature of Er Al_2@Al_2O_3nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie temperature.Based on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al_2@Al_2O_3nanocapsules was estimated to illustrate the magnetic contribution to the-S_M.The large-S_Mof 14.25 J/(kg K)was obtained under 50 k Oe at 5 K.A vital parameterˇwas introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic theory.The results demonstrate that the optimal-S_Mwill be obtained when the magnetic parameterˇis close to the theoretical coefficient.     

Preparation of w–cu nano-composite powders with high copper content using a chemical co-deposition technique

A novel chemical co-precipitation was used to produce W-70%Cu nanocomposite powders with coating structure. The precursors consisting of CuC₂O₄·xH₂O and WO₃·2H₂O were first synthesized using copper nitrate, ammonium metatungstate(AMT) and oxalic acid as the raw materials at 80?°C for 1.5?h when the concentrations of the reactants were 0.8?mol/L and the hydrogen ion concentration was 1.2?mol/L. The precursors were calcined to produce the powders with different phase components and microstructure at various temperatures. The CuWO₄ and CuO nano-powders were obtained at 300?°C, which is colder than the traditional reaction temperature (1000?°C) of CuO?+?WO₃ = CuWO₄. However, the cubic Cu₂O and Cu₂WO₄ could be formed when the calcining temperature was 600?°C. The hydrogen reduction results show that the calcined powder is reduced to obtain W-Cu composite powder at 750?°C and 800?°C. In reduction process, volatile WO₂(OH)₂ through chemical vapor transport(CVT) continuously spreads to the copper surface and is reduced to form W and the coated particle is eventually formed. This particle is Cu particle coated by W phase and the interface between W and Cu phases is semi-coherent. It is found that the average particle size of the reduced powder is 30–50?nm observed by TEM images.     

Low temperature synthesis of Co3O4 and (Co1−xMnx)3O4 spinels nanoparticles

The (Co_1?xMn_x)₃O₄ solid solution have been synthesized in water at 60 °C by soda addition to a cationic solution. XRD patterns show that spinel oxide has been obtained except for pure cobalt composition which exhibits also the presence of hydroxide and oxy-hydroxide. Therefore, to reach this composition, a different synthesis route has been developed: the cationic solution is added to the soda and for the first time Co₃O₄ nanoparticles have been synthesized by a direct precipitation in aqueous solution at low temperature. For each composition, the particles are well crystallized and exhibit a size close to 50 nm. Each particle is composed by several crystallographic domains of about 10 nm. The cubic to tetragonal transition reported in the literature for x = 0.46 is observed in between x = 0.33 and x = 0.50. Raman spectra show that substitution of Co by Mn, in the cubic phase, introduces a random high disorder. In the tetragonal phase, occupation of the octahedral site remains a random occupation, while the tetrahedral site seems to be preferentially occupied by Co ions. All these results show that the precipitation is a simple, fast and safe process to synthesize pure phase of (Co_1?xMn_x)₃O₄ spinel solid solution in aqueous media at low temperature.     

Extending LaMer's mechanism using open system for increasing forced and controlled growth of Au nano particles: Desired decreasing Fe3O4 nano particles size during simultaneous synthesis in optimized conditions

The most effective parameters were found to obtain Au/Fe₃O₄ nano particles (NPs)-oleylamine composite. Having Au NPs with the controlled maximum mean size under the forced conditions was the main aim of this study. We used the continuous flow rates of oleylamine 75% to produce Au NPs under an open system by extended LaMer mechanisms. This process decreased the mean size of Fe₃O₄ NPs synthesized simultaneously, by classic LaMer mechanism. The Fe₃O₄ NPs production was carried out without continuous adding of any iron reactant, viz. as a closed system. In the absence of gold ions, the mean size of the synthesized Fe₃O₄ NPs using 2.5 ml/min oleylamine was about 35.0 nm at 2.0 ± 0.5 °C after 120 min. This mean size was decreased to 27.2, 21.4, 16.8 and 8.7 nm, when Au NPs were simultaneous prepared using 0.5, 0.75, 1.5 and 2.5 ml/min of oleylamine, respectively, at the same conditions. Surface Plasmon Resonance (SPR) adsorption was used to evaluate Au NPs production at first 30 min, while Small Angle X-ray Scattering (SAXS) method was used to monitor the reaction progression for near-real time analysis of increasing the growth of Au NPs up to 280 min, at the optimum conditions. Changing the properties of Fe₃O₄ NPs during processes was determined by studying Magnetization, Potentiometric titration, Inductive heating and Zeta potential.     

Microstructure characterization,mechanical properties,compressibility and sintering behavior of Al-B4C nanocomposite powders

In the present work, Al-xB₄C nanocomposite (x = 0, 1, 2, 3, 4 and 5 in wt%, having the average B₄C size of 50 nm) were prepared using a high-energy ball mill. The milling times up to 16 h were applied. Then, the microstructural evolutions, mechanical properties, compressibility and sintering behavior of nanocomposites were investigated. The changes in powders morphology and microstructure during the milling process were characterized by laser diffraction particle size analyzer (LDA), SEM, XRD, EDS and TEM techniques. Compressibility and sintering behavior of milled powders compacted under different pressures (100–900 MPa) and at different sintering temperatures (500, 550 and 600 °C) were also studied. The pressing behavior of the nanocomposites was analyzed using linear compaction equations developed by Heckel, Panelli-Filho and Ge. The results showed the significant effects of B₄C amounts and sintering temperatures on the compressibility and sintering behavior of nanocomposites. The increase in the B₄C amount led to a decrease in both the compressibility rate and the sinterability of specimens. The maximum compression strength of 265 MPa and Vickers hardness of 165 VHN were obtained for Al-5 wt.% B₄C nanocomposite milled for 16 h followed by sintering at 600 °C.