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Titanium dioxide nanoparticles have great potential for use in photocatalytic applications, cosmetics, white pigments and so on. In this paper, the effect of milling time on particle size, morphology and phase composition of TiO₂ nanoparticles, prepared by mechanochemical method, was investigated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TiO₂ nanoparticles were prepared by the use of high energy ball milling of titanyl sulphate (TiOSO₄) and NaCl powders as the starting mixture in different milling durations. The milled powder was annealed at 700°C for 30 min. The NaCl powder, used as the diluent phase, was removed by washing the annealed powder with distilled water. It was found that with increasing milling time, decrease in the size of equiaxed spherical particles and increase in temperature of anatase to rutile transformation (A → R) can be observed.

Fabrication and characterization of aluminum matrix composite reinforced by Al₂O₃–AlB₁₂ particles were investigated. Al₂O₃–AlB₁₂ composite powder was first synthesized by mechanochemical route starting from Al and B₂O₃ powder mixture. Then, prepared Al₂O₃–AlB₁₂ powder was mixed with pure aluminum powder and ball milled in order to produce Al — 20 wt.% (Al₂O₃–AlB₁₂) composite. The structural evaluation of powders was studied by X-ray diffraction, scanning electron microscopy, and microhardness measurement. The results showed that through ball milling process a homogeneous distribution of Al₂O₃–AlB₁₂ particles in nanocrystalline Al matrix was obtained. This structure exhibited good thermal stability and high hardness value of 190 HV which is significantly higher than 33 HV for pure Al.

In this paper, the nanocrystalling composite Mg-Ni-TiO₂-CNTs was made by mechanical ball milling under hydrogen pressure of 5.0×10^-5Pa, The hydrogen storage properties and operation temperatures were investigated. It was found that the composite can absorb 7.5wt.% hydrogen in 60s under 5.0×10^-5Pa hydrogen pressure and desorb 6.5wt% hydrogen in 600s at 260°C under 5.0×10^-5Pa hydrogen pressure. The composite has very high absorption, hydrogen capacity and remarkable kinetic properties in hydriding /dehydeiding process. TiO₂, Ni and CNTs were used as additive to improve the hydrogen storage performance. They can be utilized as an effective catalyst to improve hydriding/dehydriding performance of hydrogen storage material and lead to pronounced enhancement on the hydrogen storage property of Mg. The results showed that the composite has potential application in the future.

The service life of industrial components is limited predominantly by Chemical corrosion/mechanical wear. The project is concerned with the investigation of the capability of Ti(Al,O)/Al₂O₃ coatings to improve the service life of tool steel (H13) used for dies in aluminium high pressure die casting.

This paper gives a general review on the research work conducted at the University of Waikato on producing and evaluating the titanium/alumina based composite coatings. The powder feedstocks for making the composite coatings were produced by high energy mechanical milling of a mixture of Al and TiO₂ powders in two different molar ratios followed by a thermal reaction process. The feedstocks were then thermally sprayed using a high velocity air-fuel (HVAF) technique on H13 steel substrates to produce a Ti(Al,O)/Al₂O₃ composite coatings. The performance of the coating was assessed in terms of thermal shock resistance and reaction kinetics with molten aluminium. The composite powders and coatings were characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD).

The present paper is focused on fabrication, characterization, and aging behavior of nanostructured Al6061 alloy prepared by mechanical milling. The milling was performed on Al6061 in a planetary ball mill under argon atmosphere for various times up to 30 h. Isothermal heat treatment was then carried out on 30 h milled powder at different temperatures up to 550^°C. The structural evolution of milled and annealed powders was studied by X-ray diffraction, SEM observation, and hardness measurements. The results showed that the final milled product was an Al–Mg–Si supersaturated solid solution having a grain size of 35 nm and a microhardness of 157 HV. Additionally, Mg₂Si precipitation between 250 and 300^°C led to an increase in hardness with the peak-aging hardness value of 207 HV after heat treatment at 300^°C for 2 h. Above this temperature, due to the dissolution of the precipitates and grain growth, the hardness values decreased to 130 HV after heat treatment at 550^°C for 3 h.

Aluminum (Al)-based materials composited of different low melting point materials were prepared by mechanical ball-milling. Hydrogen production using these materials was investigated to help resolving the safety issues associated with the storage and transportation of hydrogen. The phase composition and microstructure of the Al-based composited materials were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. As observed in this study, the addition of low melting point metals (such as Sn, Bi and In) helped to lower the initial Al-water reaction temperature and to increase the yield in the production of hydrogen. Samples of optimized compositions, Al–6% Sn–4% Bi and Al–6% Sn–4% In, were found to exhibit high hydrogen production yields of up to 448 and 515 mL, respectively. Meanwhile, their hydrogen generation rates were increased.

A mixture of Fe₂O₃ and SnO oxides has been mechanically milled to form SnFe₂O₄ spinel phase. X-ray diffraction pattern of the milled mixture shows that after milling, both peaks of Fe₂O₃ and SnO remain with a drastic decrease of their intensities and broadening. The appearance of a broad halo around 2θ ~ 31° indicates the formation of an amorphous phase. After annealing at 750°C for 1 h, SnO peaks disappear completely and new diffraction peaks emerge indicating the formation of a new nanophase i.e. SnO₂. Magnetic measurements of the as-milled mixture show a ferromagnetic behavior with saturation magnetization Ms = 6.8 emu/g which drastically decreases after annealing to 0.6 emu/g.

In the present investigation, (Cu, Cr, Fe)Al₂O₄ spinel was synthesized from decagonal quasicrystalline precursor using mechanical milling followed by air annealing. The optimum annealing temperature and time were found to be 600°C and 60 h respectively. The evolution of the spinel structure started upon air annealing at 600°C from the B2 phase formed due to milling of quasicrystalline phase for 40 h. The relevant optical property of mechanically milled and air annealed samples prepared at different temperatures (400°C, 500°C and 600°C) were evaluated by photoluminescence technique. These studies suggested the presence of emission characteristics in blue region i.e. at 430 nm.

Highly conductive glass-ceramic electrolytes are successfully prepared in the system Li₂S-P₂S₅ with 70 and 80 mol% Li₂S. The conductivities of these electrolytes are respectively 3.2 × 10^-3 and 1.0 × 10^-3S cm^-1 at room temperature. The precipitated crystals upon heat treatment of the glass are new superionic phase Li₇P₃S₁₁ and thio-LISICON II analog Li_3+5xP_1-xS₄, respectively. The crystal structure of the new phase Li₇P₃S₁₁ is analyzed and found to have a triclinic unit cell with space group of P-1 and to contain and ions. All-solid-state batteries using the Li₂S-P₂S₅ glass-ceramics are fabricated in order to evaluate the cell performance as a lithium secondary battery. The cells In/80Li₂S·20P₂S₅ (mol%) glass-ceramic/LiCoO₂ exhibit excellent cycling performance of over 500 times with no decrease in the discharge capacity (100 mAh g^-1) at limited current densities. They also worked under very high current densities of 10 mA cm^-2 when oxide- or sulfide-coated LiCoO₂ particles were used as an active material.

In this research, effect of milling time on solid state reduction of MoO₃ with carbon has been investigated. It was found that mechanical activation of a mixture of MoO₃ and carbon at ambient temperature by high energy ball milling was not able to reduce MoO₃ to metallic molybdenum. MoO₃ was converted to MoO₂ at the first stage of reduction and peaks of the latter phase in X-ray diffraction patterns were detected when the milling time exceeded from 50 hours. The main effect of increased milling time at this stage was decreasing of MoO₃ peak intensities and significant peak broadening due to decrease in size of crystallites. After prolonged milling, MoO₃ was fully reduced to nano-crystalline MoO₂ and its mean crystallite size was calculated using Williamson–Hall technique and found to be 17.5 nm.

Thermodynamic investigations also confirm the possibility of reduction of MoO₃ to MoO₂ during the milling operation at room temperature. But, further reduction to metallic molybdenum requires thermal activation at higher temperature near 1100 K.

XRD and SEM techniques were employed to evaluate the powder particles characteristics.

Nano-sized intermetallic powders have received great attention owing to their property advantages over conventional micro-sized counterparts. In the present study nano-sized MoSi₂ powder has been produced successfully from commercially available MoSi₂ (3 μm) by a mechanical milling process carried out for a period of 100 hours. The effects of milling time on size and morphology of the powders were studied by SEM and TEM and image analyzing system. The results indicate that the as-received micrometric powder with a wide size distribution of irregular shaped morphology changes to a narrow size distribution of nearly equiaxed particles with the progress of attrition milling up to 100 h, reaching an average particle size of 71 nm. Structural evolution of milled samples was characterized by XRD to determine the crystallite size and lattice microstrain using Williamson-Hall method. According to the results, the crystallite size of the powders decreases continuously down to 23 nm with increasing milling time up to 100 h and this size refinement is more rapid at the early stages of the milling process. On the other hand, the lattice strain increases considerably with milling up to 65 h and further milling causes no significant changes of lattice strain.

Magnesium AZ91D alloys reinforced with fine SiC particles (AZ91/SiCp) were fabricated by mechanical milling, hot pressing and extrusion. The properties of AZ91D alloy composites were generally improved by SiC addition. The Young's modulus and hardness increased correspondingly with SiC addition up to 20-volume percent. However, the UTS and proof stress showed a maximum value at 15-volume percent and decrease at 20-volume percent. Nevertheless, the UTS values of the 20-volume percent SiC composites increased when the milling duration was increased. The influence of the volume fraction of SiC particle and milling term on mechanical properties, microstructure and density will be discussed.

The aim of the current work is to present a new route to synthesise carbonateapatite with low cristallinity and carbonate content in the range of biological apatites. Mechanical milling has been employed for this preparation and the influence of the different conditions on the final material characteristics has been studied. A higher time of grinding is required under a CO₂ atmosphere (210 hours) than under air (135 hours). However, in the sample obtained in air, some of the starting CaCO₃ still remains.