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Transition metal ion doped ZnO nanoparticles synthesised by various methods were reported to display modified optical properties. However, there are limited reports on Mn doped ZnO prepared by mechanochemical synthesis. This paper reports on the structural and optical properties of Zn1−xMnxO nanoparticles prepared by mechanochemical synthesis in a high energy ball mill (x = 0, 0·02, 0·04, 0·06, 0·08 and 0·1) and heat treated at different temperatures (400 and 600°C). Phase analysis of the dried powders was carried out from the data obtained by X-ray diffraction of the samples. The peak shifting in X-ray diffraction patterns indicates that the Mn ions were successfully doped into the ZnO crystal lattice with successive increase in dopant levels. The morphology of the nanoparticles was analysed by field emission scanning electron microscopy. It can be seen from the field emission scanning electron microscopy images that the nanoparticles did not tend to agglomerate and the surface morphology of the ...

In this study, titanium powder mixed with different wt % of HA was coated on stainless steel (SS) substrate using high velocity oxy-fuel (HVOF) technique to produce composite coating for biomedical applications. As the addition of HA is expected to influence the bioactivity of the coatings, these coatings were investigated for bioactivity by immersing the samples in a simulated body fluid (SBF) solution for 14 days. The apatite growth rate was evaluated by measuring Ca and P concentration in the SBF using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The concentrations of Ca and P have decreased over time in the SBF, suggesting a bone like apatite precipitation on the sample surface. It was observed that pH value increased with the increase of immersion time during initial three days and a subsequent drop after 7 days. Microstructure analysis done using FESEM technique showed nucleation and growth of bone-like apatite on the surface of the coating.

The present study investigated the influence of heptane and tin process control agents on cube milled Ti–6Al–4V + 0.5 Vol% TiC (Ti–6Al–4V–0.5TiC) powder. A smaller particle size and nar-row particle distribution was observed for Ti–6Al–4V–0.5TiC powder milled with heptane, while the powder milled with tin showed relatively larger particle size and broader particle distribution due to the cold welding of particles. Hcp phase was observed in the Ti–6Al–4V–0.5TiC powder milled with tin. The formation of fcc Ti(C, H)metastable phase with high lattice strain and interstitial content in Ti–6Al–4V–0.5TiC powder milled with heptane, resulted in higher hardness compared to the powder milled with tin.

Simple doping process of Zinc (Zn) with Tin oxide (SnO 2 ) was successfully prepared by the mechanochemical process, followed by a heat treatment and leaching. The raw materials are Tin Chloride (SnCl 2 ) as a base element, Sodium Carbonate (Na 2 CO 3 ) as an oxidizer and Sodium chloride (NaCl) as a diluent, while Zinc Chloride (ZnCl 2 ) as a doping element. In this paper, we with fix wavelength investigated the effect of different concentration of Zn dopant on the optical properties of SnO 2 . The chemical formula of doped SnO 2 will be Sn 1−x Zn x O 2 . The peaks of the X-ray Diffraction (XRD) prove that all Zn had been successfully doped into SnO 2 host. The average sizes of crystalline were around 25 to 44 mm and it was calculated by using Scherrer's equation. While Ultraviolet-visible spectroscopy (UV-VIS) and photoluminescence were used to analyze the energy gap differences of pure SnO 2 and doped SnO 2 with varying Zn concentration. Results show that increasing in the concentration can decrease the volume of samples. Red shift in energy gap (E g ) with an increasing Zn concentration (x ≤ 0.06) could be attributed to the Burstein-Moss effect that relates the E g with the crystallite size of SnO 2 formed before and after the doping process. The blue shift in E g at x>0.06 was possibly due to excess oxygen and may also be affected by sudden increases in crystallite size. The emission intensity was changed inversely with the E g .

Synthetic hydroxyapatite, (HA, Ca10(PO4)6(OH)2), is an attractive and widely utilized bio-ceramic material for orthopedic and dental implants because of its close resemblance of native tooth and bone crystal structure. Synthetic HA exhibits excellent osteoconductive properties. Osteoconductivity means the ability to provide the appropriate scaffold or template for bone formation. Calcium phosphate biomaterials [(HA), tri-calcium phosphate (TCP) and biphasic calcium phosphate (HA/TCP)] with appropriate three-dimensional geometry are able to bind and concentrate endogenous bone morphogenetic proteins in circulation, and may become osteoinductive and can be effective carriers of bone cell seeds. This HA can be used in bio-implants as well as drug delivery application due to the unique properties of HA. Biomaterials synthesized from the natural species like mussel shells have additional benefits such as high purity, less expensive and high bio compatibility. In this project, HA-nanoparticles of different crys...

Hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ), having similar chemical and crystallographic structures to bone, is attractive with its bioactivity which can form a chemical bond with osseous tissue. Synthetic HA exhibits excellent osteoconductive properties. In other words, synthetic HA have the ability to provide the appropriate, scaffold or template for bone formation. The nano sized HA can be synthesized by using microwave technique. Microwave has the advantages of rapid growth, small particle size and narrow particle size distribution due to fast homogenous nucleation. Calcium oxide (CaO) was obtained by calcining egg shells at 900 °C for 2 hours. Nano HA was synthesized by mixed of di-ammonium hydrogen phosphate (DAP) and calcium hydroxide, Ca(OH) 2 and subjecting to microwave for 30 minutes at 1100 W irradiation power. Single phase HA was identified from XRD patters of the samples. The mean crystalline size of nano-HA from microwave processing was found to be in the range of 35–39 nm. Green compact of nano-HA and Ti were prepared with varying amounts of Titanium (10, 20, 30 wt. %) and sintered at 1000 °C. Pellets with 20 wt.% Ti were found to exhibit superior mechanical properties with a hardness and compression strength values of 317.0 Hv and of 66.37 MPa respectively. Scanning Electron Microscopy (SEM) micrographs showed that the grain boundary Ti is porous and has resulted in inferior densification during sintering process.

Grain refinement plays a crucial role in improving characteristics and properties of aluminum (Al) alloys. Silicon (Si) is the major alloying element their because of superior casting characteristics. Generally Sronthium (Sr), Scandium (Sc) and Aluminium-Titanium-Boron (Al-Ti-B) master alloys were added to the Al alloys to grain refine the alloys. Sr and Sc are the most widely used and a very effective element for modifying the morphology of eutectic Si, while Ti-B is commonly present in the commercial grain refiners used for Al-Si alloys. In this investigation the Sc contents were chosen in ranging of 0.02 to 0.08 wt.%. The results showed that the most adequate microstructure was obtained from the alloy modified with amount of 0.02 to 0.08 wt.% of Sc modifiers. The dendrites of the cast binary alloy were seen to have significantly refined with the addition of Sc. Alloy with 0.02 wt% Sc content does not provide much grain refinement, but refines the primary dendrites of α with consequent diminution of dendrite arm spacing. Added Sc in Al-Si cast alloys has influenced on the grain refinement and improves the hardness and tensile stress of Al-Si cast alloys. Added 0.08 wt.% Sc gave the highest value for hardness and tensile stress. The value were 95.80 Hv and 399.4 MPa respectively. From this investigation, we can conclude that the addition of modifier and grain refiner will increase hardness and tensile stress of Al-Si cast alloy. From this investigation, we can conclude that the addition of modifier and grain refiner will increase the hardness and tensile stress value of Al-Si cast alloy.

Optical properties of metal ion doped zinc oxide (ZnO) nanoparticles synthesized by various methods were reported to display different properties. Nevertheless, there are limited reports on metal ion doped ZnO prepared by mechanochemical synthesis. This paper reports the effect of aluminium doping on structural and optical properties of ZnO (Zn1‐xAlxO, x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) nanoparticles prepared by mechanochemical synthesis in a high‐energy ball mill. The samples were synthesized by milling corresponding chemical precursors in a planetary ball mill for 5 h. Diluents were used to control the agglomeration and reaction kinetics during the milling. The shifting of X‐Ray Diffraction (XRD) peaks indicated that Al ions have been successfully doped into the crystal lattice of ZnO host. Average crystallite size, was calculated based on Scherrer’s equation, was found to vary from 22 to 29 nm. Blue shift in energy gap (Eg) with increasing Al concentration (x

Remenance and coercivity in Nd2Fe14B materials are strongly dependent on the microstructural aspects like phases morphology and grain size. The coercivity (Hc) of a magnetic material varies inversely with the grain size (D) and there is a critical size below which Hc∝D6. Domain wall pinning by grain boundaries and foreign phases is the important mechanism in explaining the improvement in coercivity and remenance. Nd2Fe14B intermetallic compound with stochiometric composition was prepared from pure elements (Nd ‐99.5%, Fe—99.95%, B ‐99.99%) by arc melting in argon atmosphere. Magnetic Force Microscope (MFM) gives high‐resolution magnetic domain structural information of ferromagnetic samples. DI‐3100 Scanning Probe Microscope with MESP probes was used For MFM characterization of the samples. Magnetic domains observed in cast ingots were very long (up to 40 μm were observed) and approximately 1–5 μm wide due to high anisotropy of the compounds. Magnetic domains have displayed different image contrast and mo...

Manganese doped ZnO nanoparticles were synthesized by mechanochemical processing in a high energy ball mill (Zn1−xMnxO, x = 0, 0.02, 0.04, 0.06, 0.08, 0.1). ZnO nano particles were synthesized by milling corresponding chemical precursors in a planetary ball mill for different periods of time. Diluents were used to control the agglomeration and reaction kinetics during the milling. Diluents were removed from the milled powders by selective leaching technique and the samples were dried at 100 °C for 24 hours. Phase identification and crystallite size investigations were carried out from the data obtained by X‐ray Diffraction (XRD) analysis of the samples. The peak shifting in XRD patterns showed that Mn ions were successfully doped into the ZnO crystal lattice with successive increase in dopant levels. Average crystallite size of the nano particles is seen to vary from 16 to 30 nm. Morphology of the samples was investigated by field emission scanning electron microscope (FESEM). It can be seen from FESEM im...

This paper presents the characterization results of nanocrystalline Zinc Oxide with different crystallite sizes prepared by mechanochemical synthesis. Nano ZnO particles of different crystallite size were synthesized by high energy milling of precursor powders for various periods of time. Diluents were added to the precursor powders to reduce the agglomeration of product phase and to avoid the spontaneous reaction of precursor powders. After the milling process, diluents were selectively leached out using distilled water. X‐ray Diffraction data was used to analyze the crystallite size of the nanoparticles and also to analyze the progress of the chemical reaction during milling process. Crystallite sizes were calculated from the XRD peak broadening using the Sherrer’s formula. Crystallite sizes were seen to increase at a faster rate after 5h of milling where as bellow 5h of milling, little increase was observed. This increase in crystallite size at higher milling time could be attributed to cold welding and solid state diffusion of the nano particles as a result of high energy impacts from ball to powder collision. Scanning Electron Microscope was employed to analyze the particle morphology and size distribution of the nano ZnO powders. Ultraviolet ‐Visible (Uv‐Vis) spectroscope was employed to analyze the optical absorption of the ZnO nano particles.

Conventional Al-Cu alloys exhibit coarse grain structure leading to inferior mechanical properties in as-cast condition. Expensive thermo-mechanical treatments are needed to improve microstructure and corresponding mechanical properties. In situ Al-based composites were developed to improve mechanical properties by dispersion strengthening and grain refinement obtained by the presence of particulates in the melt during solidification. In this work Al-4Cu - 3TiB2 and Al-4Cu-3ZrB2 in situ composites were prepared by liquid casting method. XRD, electron microscopy and mechanical tests were performed on suitably sectioned and metallographically prepared surfaces to investigate the phase distribution, hardness and tensile properties. It was found that the reinforcement particles were segregated along the grain boundaries of Al dendrites. Tensile fracture morphology for both Al-4Cu - 3TiB2 and Al-4Cu-3ZrB2 were analyzed and compared to determine the fracture propagation mechanism in the composites. Al-4Cu-3ZrB2 in situ composites displayed higher strength and hardness compared to Al-4Cu-3TiB2 which could be ascribed to the stronger interfacial bonding between the Al dendrites and ZrB2 particulates as evidenced from fractographs.

Aluminium (Al) based in-situ metal matrix composites (MMCs) have better properties and performance compared to ex-situ MMCs. In this research, aluminium-copper (Al-Cu) alloy was reinforced with 3 and 6wt.% titanium diboride (TiB 2 ). Al-MMCs has been fabricated with salt route reaction process at 800 °C via potassium hexafluorotitanate (K2TiF 6 ) and potassium tetrafluoroborate (KBF 4 ) salts. Hardness vickers tester and Gamry-Electrod Potentiometer were used to characterize the hardness properties and to determine the corrosion rate of Al-Cu alloys. From results obtained, increased TiB 2 contents will increase the hardness of Al-Cu alloys. Increased of TiB 2 contents also will increase the corrosion rate of Al-Cu alloys. Al-Cu with 3wt.%TiB 2 gave the good properties of corrosion when the wear rate recorded the lowest value compare to Al-Cu alloy itself and 6 wt.% TiB 2 . The corrosion rate of Al-Cu with 3wt.TiB 2 was 16.15, while Al-Cu and Al-Cu-6wt%TiB2 were 22.5 and 58.7 mm/y respectively.

Conductance values of nimesulide have been determined in water in 0.1, 0.2, 0.4, 0.6, 0.8, 1 and 2 mol dm-3aqueous solutions of hydrotropic agents (sodium benzoate, sodium salicylate, sodium bromide and nicotinamide) at temperatures 298.15, 303.15, 308.15 and 313.15 K. The conductance values have been used to evaluate the limiting molar conductance and association constants by means of Shedlovsky extrapolation technique. Thermodynamic parameters for the association process of nimesulide in aqueous solutions of hydrotropic agents have also been calculated.