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Purpose This study aims to compare the influence of different solid lubricants on the friction stability of a non-asbestos disc brake pad. Design/methodology/approach Three brake pads were developed using three lubricants, namely, non-asbestos brake pad with sulfide mix (NASM), non-asbestos brake pad with bismuth sulfide (NABS) and non-asbestos brake pad with molybdenum disulfide (NAMO). Sulfide mix was indigenously developed by physically mixing friction modifiers, alkaline earth chemicals and various metallic sulfides homogeneously dispersed in graphite medium. The physical, chemical, mechanical and thermal properties of brake pads were characterized as per industrial standards. The tribological performances were studied using the Chase testing machine as SAE-J661-2012. The worn surface of the pads was studied using scanning electron microscope to analyze the dominating wear mechanism. Findings NASM was excellent in fade as well as wear resistance. NABS was better from a wear point of view, but fade resistance was moderate despite its higher cost. NAMO fared average in fade and wear despite its excellent dry lubricating properties. NASM was excellent in terms of fade as well as wear resistance. Originality/value Among the selected metal sulfides, the indigenously developed sulfide mix was better than the other two sulfides, which indicates that the synergetic effect of metal sulfides was always preferable to the individual sulfides.

In modern times it is seen that the use of aluminum alloys has increased greatly in automobile, aerospace, marine, and various other fields. This is due to the fact that aluminum alloys have superior advantages when it comes to corrosion resistance, strength to weight ratio characteristics, and high machinability when it is compared with steel. In this paper a study on the mechanical, tribological properties and microstructure of aluminum alloy with variations in Nickel (Ni) and Iron (Fe). Previous studies that have been conducted in this field have dealt with aluminum additives of different compositions with the study of only mechanical properties or microstructure. Our project deals with the study in the changes of properties and microstructure analysis of Iron(Fe) and Nickel(Ni), aluminum-based alloy added to which the tribological studies and the correlation is studied with the variations in the metal concentration, Thus the study and development of these alloys are important as it paves the way for the new generation of mechanical components with superior properties. Also, our paper deals with the fabrication of a brake disc rotor with the most suitable alloy among the three. The tensile strength, hardness, and surface characteristics of all the profiles were studied in detail and presented. The 7% of Iron powder in the profile has the highest tensile strength.

The main purpose of this work is to prepare magnesium metal matrix composite in an attempt to improve its mechanical and wear properties. To achieve this objective, four compositions Mg (AZ91D), Mg SiC 2%, Mg SiC 3%, Mg SiC 5% were selected. Among various fabrication techniques available for the preparation of Magnesium metal matrix composite, Stir casting was chosen due to its simplicity, low cost and it can be used for mass production. The prepared composite was subjected to tensile test, Vickers hardness test, optical microscopy and wear studies. The tensile strength was found to increase 45% on the incorporation of 2 wt% SiC particle. The hardness of composite shows a gradual increase of 34% on increasing the weight percentage of SiC particle to 5 wt%. The optical micrograph of 2 wt% SiC reinforced composite shows a uniform distribution of particles within the matrix. The 5 wt% SiC reinforced magnesium alloy composite was found to have a minimum wear rate of 0.89 mm3/Nm and maximum co-efficient of friction 0.425.

AA6061 matrix composites are becoming indispensable in automotive, aircraft, marine, and structural applications because of their lightweight, good mechanical, corrosion, and wear resistance properties compared to traditional materials. The present study evaluates the effect of silicon carbide and silicon carbide/alumina particle with 5 wt% SiCp, 7 wt%SiCp, and 7 wt%SiCp/3 wt% Al2O3 on the mechanical, microstructural, and wears performance of prepared composites. The additions of reinforcement increases the mechanical and wear resistance of composites compared to cast aluminum alloy. The AA6061 alloy with 7 wt%SiCp/3 wt% Al2O3 composite has obtained a maximum tensile strength, hardness and wear resistance of 134.3 N/mm2, 35VHN and 17.27 × 10-5mm3/Nm, respectively. The optical micrograph shows the dispersion of reinforcement particles is uniform throughout the aluminum alloy matrix.

The usage of magnesium alloy has grown in the field of automotive, aviation, and marine sectors due to its significant characteristics of lightweight, high specific strength, impact, and wears resistance. The present investigation is to evaluate the wear characteristics of magnesium AZ91E alloy nanocomposite with SiCnp by pin-on-disc wear tester using dry sliding conditions. The dry sliding wear investigations were carried out on a 200 m constant sliding distance with a load of 10 N, 20 N, 30 N, and 40 N at various sliding speed (0.25 m/sec to 0.75 m/sec). The wear rate of nanocomposites significantly decreased with the normal load at a high sliding speed of 0.75 m/sec as compared to AZ91E alloy. The result showed that the coefficient of friction has gradually increased with increase in the load 10 N to 40 N at different sliding speed. It has varied from 0.307 to 0.472.

Super heater is an inevitable component of any boiler system and failure of super heater leads to breakdown of whole plant. The integration of efficient quality welding technologies for dissimilar metals will be a key component in the successful weld quality for power plant components. In this investigation, an attempt has been made to study the dissimilar material AISI304 and SA213T22 tungsten inert gas welding is performed under different welding conditions current (100, 115, 130 Amps), gas flow rate (6, 8, 10 ltr/min), speed (2, 2.5, 3 mm/sec) and micro structure analysis performed to find influence of fusion heat. The Taguchi analysis is implemented to obtain single response optimization and grey relational analysis used to attain multi response for best yield strength, the ultimate strength, Vickers hardness and the elongation of the metals.

The present study deals with the wear characteristics of magnesium based metal matrix composites reinforced with alumina nano particles (50nm) under stir casting process. The wear test is conducted during dry sliding condition using pin on disc tester machine configuration with hardened steel counter-face, the load applied is 10N and 20N with different sliding speed (200,400,600 & 800 rpm) under the time intervals of 0-180 sec at room temperature. The wear decreases with addition of alumina nano particle under normal load at high sliding speed and also improves the co-efficient of friction from 0.095 to 0.55.

RF magnetron sputtering technique was employed to fabricate gallium zinc oxide ((Ga)ZnO) semiconductor thin film transistor (TFT) at 100°C. X-ray diffraction and Scanning electron microscopy were used to identify the structure and morphology of (Ga)ZnO layer. Self-heating effect was very much reduced when compared with output characteristics of a TFT fabricated using undoped zinc oxide. The low deposition and processing temperatures make (Ga)ZnO-TFTs very promising for the flexible electronics.

In the present study, alumina reinforced copper metal matrix composites were prepared by stir casting method. Three different specimens were prepared by changing the weight ratio of alumina to copper. The samples were prepared by adding 10%, 20% and 30% alumina to copper matrix. The three specimens were subjected to mechanical, thermal and corrosion testing, in order to find out the properties of the material. Various mechanical tests like hardness, impact and corrosion were performed including thermal conductivity to understand the behaviour of the specimens under combined loads. Specimen number 2 which was 80%-20% copper to alumina was found to be the best combination for such type of applications.

The present study is to fabricate AZ91E alloy matrix composite by varying the Bagasse ash particle (50μm) content (0, 5, 7.5, and 10wt%) via vacuum stir casting technique. The samples were characterized for its mechanical and microstructure properties. The mechanical properties of BAP reinforced composites were evaluated as per the ASTM standard and compared to unreinforced AZ91E alloy. The effect of reinforcement and distribution of BAP has been examined through a scanning electron microscope. The results of AZ91E magnesium alloy with 10wt% of BAP have found to have maximum tensile strength. The impact strength and hardness shows a marginal increase with increasing bagasse ash particle.

This paper describes the obtention of LaCoO 3 nanopowders by the co-precipitate method with ammonium hydroxide from solvent such as water, ethyl alcohol and ethylene glycol. The crystalline structure and average particle size are dependent of type-solvent. The XRD patterns indicated that the LaCoO 3 nanopowders prepared with water and ethyl alcohol exhibit a pure perovskite-type LaCoO 3 in the rhombohedra structure. The average diameter of the particles prepared with ethyl alcohol and water are 27 ± 4.49 nm and 64.4 ± 12.92 nm respectively. High resolution transmission electron microcopy revealed an oriented attachment mechanism for the growth of aggregated LaCoO 3 nanocrystals. Room temperature magnetization results of the heat treated LaCoO 3 nanopowders exhibited a paramagnetic behavior. The average particle size and formation temperature of LaCoO 3 obtained in this study is comparatively lower than those reported in the literature.

Europium-doped Gadolinia (Eu-Gd2O3) phosphor nanoparticles have been synthesized by a reverse microemulsion system using cyclohexane as the oil phase, a non-ionic surfactant Igepal CO 520 and the mixed aqueous solutions of gadolinium III nitrate hexahydrate and Europium III nitrate hexahydrate as the water phase. The synthesized and calcined powders were characterized by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). The XRD results showed that the powders were cubic phase of Gd 2O3 after being calcined in the air at 1,000�C. DTA and FTIR also evidenced the formation of Gd2O3 at 1,000�C. SEM revealed that the particle size decrease with increase in Eu content. EDS confirmed the presence of Gd and Eu phase in the nanopowders calcined at 1,000�C. The photoluminescence studies indicated that a strong emission peak at 610nm is a characteristic red emission of Eu3+, and the emission intensity increases with increase in Eu content. � 2012 Copyright Taylor and Francis Group, LLC.

Nanoparticles of surfactant modified MgFe 2 O 4 have been synthesized by reverse micelle processing using tertiary system of heptane/Igepal CO 520/H 2 O. The effect of water to surfactant ratio on the particle size and magnetic property has been studied. X-ray diffraction analysis confirms that MgFe 2 O 4 nanoparticles are crystalline in nature with cubic spinel structure. The average particle size increases with increase in water to surfactant ratio. The Fourier transform infrared (FTIR) analysis confirms that the surface of MgFe 2 O 4 nanoparticles was coated with surfactants. The saturation magnetization ranged from 14.4 to 40.05 emu/g was measured by Superconducting Quantum Interference Device Magnetometry (SQUID).

Indium oxide nanoparticles of ∼12 nm were synthesized by a simple chemical route using indium(III) nitrate. Nanoparticles are formed after calcining the dried precursor in air at 400 °C for 10 h. TEM analysis showed that the morphology and size of the In 2 O 3 samples were affected by ultrasonication. FTIR and Raman studies reveal that the nanoparticles are single-phase cubic structure of In 2 O 3 . NEXAFS study was used to quantify the Indium and oxygen valence state. Magnetic behavior of indium oxide nanoparticles was found to be diamagnetic. UV spectra show a weak band at ∼308 nm corresponds to optical band gap energy of 4.03 eV.

Nanopowders of MgFe 2 O 4 have been synthesized by the novel and facile reverse microemulsion route. The effects of changing the continuous phase on the particle size and the magnetic property have been studied. The average particle size, morphology and saturation magnetization are shown to be dependent on the continuous phase. The average diameters of the particle prepared with heptane are 20.9 ± 4.3 nm. On the contrary, the product with toluene and cyclohexane is highly aggregated. The values of saturation magnetization for our samples prepared with heptane, toluene and cyclohexane are 14.5, 30 and 37 emu/g.

Gadolinium aluminate (GdAlO3) perovskite nanopowders were synthesized using microreactors made of poly(oxyethylene) nonylphenyl ether/water/cyclohexane microemulsions. Differential thermal analysis confirmed the formation of GdAlO3 at 902°C. X-ray diffraction analysis (XRD) of all the powders indicated the formation of single-phase perovskite structure on calcination. The average crystallite size was found to increase with increase in water-to-surfactant molar ratio and the average particle size increases from 23 to 28 nm on increasing the molar ratio from 4 to 8. The Fourier transform infrared (FTIR) spectra show that the lower frequency bands are assigned to M–O vibrations, which are characteristic vibrations of perovskite structure compounds.

Li doped SnO2 nanoparticles were synthesized using an emulsion precursor derived from a mixed-metal and oleic acid solution. The precursors and derived oxide powders were characterized by differential thermal analysis, thermogravimetric analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The XRD studies reveal that the material is assigned to be SnO2 tetragonal Cassiterite phase. The average particle size as determined from TEM varies in the range 12–181 nm. The amount of Li content in the sample determined by ICP-AES was found to 1.615 wt%.

Lanthanum Aluminate (LaAlO3) nanoparticles have been synthesized at low temperature using the sol–gel method, in combination with the self-propagating combustion technique, by adding a little stearic acid as dispersant during citric acid addition. Calcinated nano-LaAlO3 has been characterized using DTA-TGA, X-ray diffraction, infrared spectroscopy and transmission electron microscopy. X-ray diffraction studies confirm the formation of LaAlO3 at low temperature by adding stearic acid. FTIR analysis shows the characteristic bands at 660 and 449 cm−1 were those for LaAlO3. TEM micrographs showed an average particle size of ∼25 nm without stearic acid, which were in contrast to the highly agglomerated particle with stearic acid. The influence of the stearic acid on the morphology of nano-LaAlO3 was also discussed.

In this paper, we describe variations in an oleic acid and metal nitrate emulsion during the process of forming superfine LaAlO3 crystallites from the mixture of oleic acid and metal nitrate precursors. The influence of oleic acid to metal nitrate ratio (ol/mn) on the phase and morphology were characterized by Differential thermal analysis (DTA-TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). X-ray diffraction analysis of the powders with ol/mn ≤1 indicated the formation of pure rhombohedral LaAlO3 at 800 °C. The optimal ratio of the oleic acid to metal nitrate for preparing fine LaAlO3 nanopowders of 29 nm was 0.5. The TEM micrographs indicated morphological change (sphere, cube, triangle, etc.) as the oleic acid to metal nitrate ratio increases from 0.5 to 2.

A modified solution combustion approach was used in the preparation of nanosize LaAlO3 (∼23.6 nm) using mixture of citric acid and oxalic acid as fuels with corresponding metal nitrates. The synthesized and calcined powders were characterized by Fourier transform infra red spectrometry (FTIR), Differential thermal analysis-Thermogravimetry analysis (DTA–TGA), X-ray diffractometry (XRD) and Transmission electron microscopy (TEM). The FTIR spectra show the lower frequency bands at 656 and 442 cm−1corresponds to metal–oxygen bonds (possible La–O and Al–O stretching frequencies) vibrations for the perovskite structure compound. DTA confirms the formation temperature of LaAlO3 varies between 830–835 °C. XRD results show that mixture of fuels ratio is influential on the crystallite size of the resultant powders. The average particle size of LaAlO3-1 as determined from TEM was about 41 nm, whereas for LaAlO3-2 and LaAlO3-3 samples, particles are seriously aggregated.

Magnesium aluminate (MgAl2O4) spinel nanoparticles were synthesized using micro-reactors made of poly(oxyethylene) nonylphenyl ether/water/cyclohexane microemulsions. The influence of water to surfactant ratio on the resulting particle size of MgAl2O4 has been studied. The average particle size was found to increase with increase in water to surfactant molar ratio and the average particle size increases from 13 to 17 nm on increasing the molar ratio from 2 to 8. Water to surfactant ratio is a major factor in controlling the final particle size of MgAl2O4 powder. X-ray diffraction analysis of all the powders indicated the formation of single-phase spinel structure on calcination. The FTIR spectra show the lower frequency bands are assigned to AlO6 octohedra in MgAl2O4.

Alumina-zirconia composite powders were produced by sol-gel autocombustion. 20 wt.% ZrO2-Al2O3 mixture precursor solutions were chelated by citric acid ions at different pH. DTA analysis shows sluggish decomposition at low pH, whereas there was rapid decomposition at high pH = 9. XRD patterns of the calcined powders showed that well crystallized powder with 100 % tetragonal phase and α-alumina phase is produced when pH = 0.58 (without ammonia addition). TEM characterization of composite powders revealed homogenous distribution of nanosized zirconia particles in the alumina matrix. FTIR analysis shows peaks at 590 cm−1 and 454 cm−1, which are identified as the characteristic absorption bands of Zr-O and Al-O.

This letter describes the synthesis of CaAl 12 O 19 powders using micro reactors made of Igepal CO520/water/cyclohexane microemulsions. Characterization of the powder was done by DTA-TGA, X-ray diffraction, Scanning electron microscopy, Fourier Transform Infrared Spectroscopy. The XRD results show that the hexagonal CaAl 12 O 19 powders have been obtained at 1200 °C for 2 h. The SEM examination shows that the hexagonal CaAl 12 O 19 has plate-like grain morphology with most of the grain took the form of hexagonal platelets with-developed faces. The FTIR spectra show the lower frequency bands are assigned to AlO 6 octohedra and AlO 4 tetrahedra in CaAl 12 O 19 .

Gadolinium doped ceria (Gd–CeO 2 ) nanoparticles have been synthesized by an reverse microemulsion system using cyclohexane as the oil phase, a non-ionic surfactant Igepal CO 520 and their mixed aqueous solutions of gadolinium III nitrate hexahydrate and cerium III nitrate hexahydrate as the water phase. The control of particle size was achieved by varying the water to surfactant molar ratio. The synthesized and calcined powders were characterized by thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The XRD results show that all the samples calcined at 700 °C were single phase cubic fluorite structure. The average size of the particle was found to increase with increase in water to surfactant molar ratio ( R ). The mean diameter of the particle for various value of R varies between 8–15 nm (SEM) and 7.5–11 nm (TEM), respectively. EDS confirm the presence of gadolinia and ceria phase in the nanopowder calcined at 700 °C. FTIR analysis was carried to monitor the elimination of residual oil and surfactant phases from the microemulsion-derived precursor and calcined powder. Raman spectroscopy and DTA evidenced the formation of a solid solution of gadolinium doped ceria at room temperature.

A consolidation technique based on gelling property of starch was used to prepare alumina ceramics. Slurry containing alumina powder, dispersant and small amount of starch (2-3.5 wt.% of powder weight) was cast into a nonporous mould and heated to gelation temperature to produce a rigid green body. A defect free green body was obtained and the total linear shrinkage during drying was 2-3% and the green density observed was 64% of theoretical value. After complete drying, ceramic compacts were sintered without debinding operation. Sintered density of 99.4% was achieved after sintering at 1600 �C for 2 h. Flexural strength values of dried and sintered alumina were ?10 and 247 MPa, respectively. The sintered ceramics showed an extremely dense microstructure. � 2009 Elsevier Ltd. All rights reserved.

Pure LaAlO 3 nanopowders were synthesized using a emulsion precursor derived from a mixed-metal and oleic acid solution. The precursors and derived oxide powders were characterized by differential thermal analysis, thermo gravimetric analysis, infrared spectroscopy, X-ray diffraction and transmission electron microscopy. Pure LaAlO 3 phase was synthesized at 800 °C for 2 h in air directly from amorphous precursors, without the formation of intermediate phase. The average particle size as determined from TEM is 60 nm. The FTIR analysis was carried to monitor the elimination of oleic acid from emulsion-derived precursor and calcined powder.

Nanocrystalline α-Al2O3 powders have been prepared by pyrolysis of a complex compound of aluminum with acetylacetone. The volumetric ratio (alumina to acetylacetone) of the starting feedstock has been shown to be a critical factor for the formation of nano α-Al2O3 powders. The optimum calcinations temperature of the precursor powder for crystallization of nano α-Al2O3 was found to be 1000°C for 2 h. Transmission electron microscopy (TEM) micrographs showed, the obtained materials could be modified from segregated nanoparticle to aggregates of nanoparticle with decrease in the volume ratio of alumina to acetylacetone from 8:2 to 5:5 in the precursor solutions. Fourier transform infrared spectra (FTIR) analysis show peak at 450 cm−1 corresponds to α-Al2O3 at 1000°C.

The precursor for combustion synthesis was a mixed citrate/nitrate gel prepared from aluminium nitrate, zirconium oxychloride and citric acid. The combustion synthesis of this gel produces nanometer-sized zirconia–alumina nanopowder. The influence of citrate/aluminium nitrate molar ratio of the precursor on the combustion rate and phase transformation was investigated. The α-Al 2 O 3 phase transformation temperature differs with the citrate/aluminium nitrate molar ratios. X-ray diffraction analysis shows that the phases present at 1200 °C are α-Al 2 O 3 and t-ZrO 2 irrespective of initial citrate/aluminium nitrate molar ratio. TEM micrograph of calcined powder revealed that the particles size is significantly influenced by the citrate/aluminium nitrate molar ratio. EDAX confirms the presence of alumina and zirconia particle in the nanopowder calcined at 1200 °C.

Zirconia- and silica-doped zirconia nanopowders with 5, 10, 15 and 20 wt.% have been prepared by oxalate processing. DTA confirms the formation of tetragonal to monoclinic zirconia takes place at higher temperature in the presence of silica. X-ray diffraction analysis indicates that the monoclinic content decreases with increase in silica content. FT-IR has been used to elucidate the presence of Si–O–Si network in silica-doped zirconia nanopowders. The TEM image indicates that the zirconia nanoparticle size decreases with increase in silica content with a mean size of 15–40 nm.

Silica aerogel blankets have been synthesized by ambient drying technique using cheap water glass as the silica source and glass wool modified by alumina sol. One step solvent exchange and surface modification were simultaneously conducted by immersing the wet hydrogel blanket in EtOH/TMCS/hexane solution. The synthesized silica aerogel blanket was light with the density of 0.143–0.104 g/cm3 and 89.4–95% porosity. The microstructure of silica aerogel blanket exhibits a porous structure consisting of glass fibers of diameter ∼2.5 μm interconnected with solid silica clusters (5–20 μm).

Nanosized alumina powders have been prepared via reverse micelle and sol-gel processing. By stepwise hydrolysis using aqueous ammonia as the precipitant, hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of microemulsion consisting of cyclohexane as the oil phase, poly(oxyethylene) nonylphenyl ether (Igepal CO-520) as the non-ionic surfactant, and an aqueous solution containing aluminium nitrate as the water phase. The synthesized and calcined powders were characterized by thermogravimetry-differential thermal analysis, transmission electron microscopy, and scanning electron microscopy. The XRD analysis showed that the complete transformation from γ -Al2O3 nanocrystalline to α-Al2O3 was observed at 1100°C. The resulting alumina nanopowder exhibits particle agglomerates of 135–200 nm in average diameter occur when they calcined at 1200°C. The average particle size was found to increase with increase in water to surfactant (R) molar ratio.

This article presents the experimental study of thermomechancial, free vibration, and damping characteristics by reinforcing barium titanate nanopowder (0, 1, 3 and 5 wt%) in the epoxy matrix using the resin casting method. Theoretical study is also carried out to study the vibration characteristics of barium titanate/epoxy nanocomposites. Dynamic mechanical analysis shows an increase in the storage modulus and glass transition temperature with a maximum value of 6400 MPa and 154°C for 3 wt% barium titanate nanopowder in epoxy polymer matrix. Dynamic results show that the second phase barium titanate nanopowder dispersion in the epoxy matrix enhances the internal damping of laminates up to 3 wt%.

This article is focused on the preparation of barium titanate nanopowder/epoxy composites and studying the effect of barium titanate nanopowder on improving mechanical and thermal characteristics o...

Calcium oxide (CaO) doped Alumina–zirconia fibers were prepared by sol-gel process. The starting materials used for the preparation of alumina and zirconia sol were aluminium-tri-isopropoxide and zirconium oxychloride, respectively. Alumina sol and zirconia sol were mixed in definite proportions, so that the final composition contains 10 wt% ZrO2. CaO was introduced into the mixed sol in the form of calcium nitrate such that the final composition contains 1 and 2 wt%. Alumina–zirconia fibers were prepared from the mixed sol containing CaO, respectively. Sintered alumina–zirconia fiber has α -Al2O3, t-ZrO2, and m-ZrO2 phases. The phase transition to α -Al2O3 takes place at lower temperature in the presence of CaO. The addition of CaO increases the grain size.

Al2O3–ZrO2 nanopowders containing 5–20 wt.% ZrO2 was synthesized by a simple aqueous sol–gel method using a citrate polymeric precursor derived from aluminium nitrate, zirconium oxychloride and citric acid mixed solution. The thermal decomposition of the precursor and subsequent formation of α-Al2O3 was investigated by differential thermal analysis. X-ray diffraction analysis shows that the phases present at 1200 °C are α-Al2O3 and t-ZrO2 irrespective of zirconia content. The t-ZrO2 is found to increase with increase in zirconia content. FTIR also confirms the formation of α-Al2O3 incorroboration with X-ray studies. TEM micrograph of calcined powder revealed nanosize spherical particle of ∼75 nm. EDAX confirmed the presence of alumina and zirconia particle in the nanopowder calcined at 1200 °C.

Electro-spun fabricated TiO2 nanofibers were prepared by simple electro-spinning method, in subsequent step silver (Ag) was deposited using precipitation method and obtained Ag-TiO2 composite nanofibers. The properties and morphology of these prepared composite nanofibers were characterized by XRD, SEM, EDX, and TGA. The prepared electro-spun composite nanofibers were applied as catalyst for the photodegradation of Congo-red under immited solar light in aqueous solution. Result reveals that, Ag loaded TiO2 composite nanofibers were effectively increased photodegradation of Congo red compared with pure TiO2 nanofibers in analogous condition. As a result, 92.0% decomposition of Congo red was obtained by using 5 wt% of Ag loaded TiO2 composite nanofibers at room temperature in short reaction time using 300 W of solar light. In addition, photodegradation of Congo red was also studied under different experimental conditions such as amount of Ag loaded in TiO2 nanofibers and contact time. Moreover, we also studied sintering effect on TiO2 nanofibers and their consequent effect on photodegradation reaction. After completion of reaction, the nanofibers can be easily separated by filtration process and reused several times without significant loss of activity. Overall study reveals that, Ag–TiO2 composite nanofibers were strongly enhanced the surface activity for the photo catalytic degradation of Congo red under ambient condition.

This paper presents the experimental study of free vibration and damping characteristics of hybrid nanocomposite laminates by reinforcing short fibre chopped strand mat and organically modified montmorillonite clay (0, 1, 3 and 5�wt.%) in the vinyl ester matrix by hand lay-up technique. Theoretical study is also carried out to study the vibration and damping characteristics of hybrid nanocomposites. Dynamic result shows that the second phase nanoscale dispersion in the matrix and E-glass fibre significantly enhances the internal damping of hybrid composites. � 2007 Elsevier B.V. All rights reserved.

Alumina and alumina-zirconia minispheres were prepared by sol-gel process. The starting materials used for the preparation of alumina and zirconia sol were aluminium-tri-isopropoxide and zirconium oxychloride, respectively. Alumina sol and zirconia sol were mixed in definite proportions, so that the final composition contained 5, 10, 15, and 20 wt.% ZrO 2. The sintering behavior of alumina and alumina-zirconia minispheres were studied by sintering at 1400, 1500, and 1600�C. X-ray diffraction analysis showed the presence of ? -Al 2O 3 in alumina minispheres and ? -Al 2O 3 and t-ZrO 2 in minispheres containing 5 wt.% ZrO 2 sintered at 1400�C. Monoclinic ZrO 2 was also present in the minispheres containing higher amounts of ZrO 2 and sintered at higher temperatures. Scanning electron microscopic observation revealed progressive densification with increasing sintering temperature and zirconia content. The density of the sintered spheres was found to be the highest for spheres containing 20 wt.% ZrO 2 sintered at 1600�C.

Alumina fibres and alumina-zirconia fibres were prepared by sol-gel process. The starting materials used for the preparation of alumina and zirconia sol were aluminium-tri-isopropoxide and zirconium oxychloride respectively. Alumina sol and zirconia sol were mixed in definite proportions, so that the final composition contains 10 wt.% ZrO 2. Alumina and alumina-zirconia fibres were prepared from the alumina sol and mixed sol respectively. MgO was introduced in the fibres by adding MgNO 3 into the sol. Sintered alumina fibre has ?-Al 2O 3 phase and alumina-zirconia fibre has ?-Al 2O 3 and t-ZrO 2 phases. The phase transition to ?-Al 2O 3 takes place at higher temperature in the alumina fibre with MgO, whereas the effect is less in alumina-zirconia fibre. The addition of MgO reduces the grain size and increases the tensile strength. � 2005 Elsevier Ltd. All rights reserved.

α-Al 2 O 3 -t-ZrO 2 nanopowders were prepared by calcining an emulsion precursor obtained by mixing oleic acid, aluminium nitrate and zirconium chloride oxide octahydrate in aqueous solution. Batches of the precursor powders were calcined at different temperatures and a terminal product of nano α-Al 2 O 3 -t-ZrO 2 composite powders were obtained at 1100 °C for 2 h, indicating that the overall process is effective. The average grain size as determined from TEM varies between 20 and 50 nm.

In this research, a sol–gel autocombustion route has been proposed to synthesize alumina–zirconia nanopowder, using aluminium nitrate, zirconium oxychloride and various fuels such as citric acid, acetylacetone, oxalic acid and urea. The phase analysis and particle size in the presence of different fuel were compared. The results showed 100% tetragonal phase as well as particle size of ∼60 nm in the presence of citric acid. FTIR confirms the formation of α-Al2O3 in corroboration with X-ray studies.

LaFeO3 nanoparticles of different sizes are prepared by varying the molar concentration of oleic acid to metal nitrate using emulsion combustion method. X-ray diffraction analysis confirms that LaFeO3 nanoparticles are crystalline in nature with an orthorhombic structure. The average particle size and saturation magnetization decreases from 56 to 32nm and 0.20 to 0.08emu/g, as molar concentration of oleic acid to metal nitrate increases from 0.25 to 1. The Fourier transform infrared (FTIR) spectra show the lower frequency bands are assigned to Fe-O stretching vibration (579cm -1) and O-Fe-O deformation vibration (475 and 400cm-1). The experimental results suggest that molar concentration of oleic acid to metal nitrate plays an important role in the particle size and magnetic property of combustion synthesized lanthanum ferrite nanoparticles. Copyright � Taylor & Francis Group, LLC.

Cobalt aluminate (CoAl2O4) nanopowders were synthesized by reverse microemulsion process using cyclohexane, a nonionic surfactant, and aqueous solutions of cobalt (II) nitrate hexahydrate and aluminum nitrate nonahydrate. The influence of water to surfactant molar ratio on the size of powders has been studied. The X-ray diffraction analysis shows that the powders calcined at 1000 �C have single phase cubic spinel structure. The average size of the particles increases with increasing water to surfactant molar ratio. The mean diameter of the particles varies between 42 and 57 nm. The Fourier transform infrared spectra also confirm the formation of CoAl2O4. Magnetization study reveals that the CoAl 2O4 sample exhibits superparamagnetic behavior. � 2010 Elsevier B.V. All rights reserved.

In this research, a sol-gel auto combustion route has been proposed to synthesize LaAlO3 nanopowders, using lanthanum nitrate, aluminum hexahydrate, and different fuels such as citric acid, oxalic acid, and tartaric acid. The formation temperature of LaAlO3 and its crystallite size in the presence of different fuels were compared together. The results showed that the lowest formation temperature as well as the smallest crystallite size in the presence of citric acid was 750�C and 28.7nm. Copyright � Taylor & Francis Group, LLC.

Pure LaAlO 3 nanopowders were synthesized using a emulsion precursor derived from a mixed-metal and oleic acid solution. The precursors and derived oxide powders were characterized by differential thermal analysis, thermo gravimetric analysis, infrared spectroscopy, X-ray diffraction and transmission electron microscopy. Pure LaAlO 3 phase was synthesized at 800 °C for 2 h in air directly from amorphous precursors, without the formation of intermediate phase. The average particle size as determined from TEM is 60 nm. The FTIR analysis was carried to monitor the elimination of oleic acid from emulsion-derived precursor and calcined powder.

In this research, a sol-gel auto combustion route has been proposed to synthesize alumina-ceria composite powder, using aluminium nitrate, cerium(III) nitrate hexahydrate and various fuels such as citric acid, acetyl acetone and oxalic acid. DTA shows the phase transformation of ?-Al2O3 and CeO2 varies with fuel. XRD confirms the formation of ?-Al2O3 and CeO2 phase irrespective of fuels at 1200 �C. X-ray line broadening results showed smallest crystallite size of ?-Al2O3 and CeO2 is produced in the presence of citric acid. SEM micrograph revealed homogenous distribution of ceria nanoparticle in the alumina matrix. FTIR analysis show peaks at 460 and 400 cm-1 corresponds to ?-Al2O3 and CeO2 formation at 1200 �C. � 2008 Elsevier B.V. All rights reserved.

Nanocrystalline Al2O3–ZrO2 powder was synthesized by a simple method using oxalic acid as a chelating agent. The formation temperature of α - Al2O3 was investigated by differential thermal analysis. X-ray diffraction (XRD) analysis shows that t-ZrO2 was stabilized in alumina matrix with oxalic acid content 0.5 M and 1 M, respectively. In addition, the data from XRD showed α-Al2O3 and t-ZrO2 phase can be formed at 1100°C with 1 M oxalic acid content. Transmission electron microscope (TEM) micrograph of calcined powders revealed as the oxalic acid content in the precursor solutions is increased from 0.25 M to 0.5 M concentration. The obtained materials could be modified from segregated nanoparticles to agglomerated nanoparticles and finally to large agglomerate with 1 M concentration of oxalic acid. The Fourier transform infrared spectra (FTIR) confirms the formation of α-Al2O3 in corroboration with X-ray studies.

Alumina fibres were prepared by sol-gel process. The sol was prepared by mixing aluminium-tri-isopropoxide in distilled water and refluxed in the presence of acid catalyst. Binder was added in different amount to the sol to obtain spinnability. At the appropriate viscosity, the sol was taken in a syringe and fibres were drawn in the ammonia solution. The fibres were dried at room temperature and then sintered at 1600 �C for 2 h, ?-alumina is the only phase present in the sintered fibres. Differential thermal analysis indicated that the phase transition to ?-alumina takes place at 1100 �C. Thermogravimetric analysis indicated the removal of most of the volatile up to 600 �C. Scanning electron microscopic analysis reveals dense microstructure is formed with 10 wt.% hydroxyl ethyl cellulose. The tensile strength is found to be good for sample containing 10 wt.% hydroxy ethyl cellulose. � 2005 Elsevier B.V. All rights reserved.