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Showing papers in "Nanostructured Materials in 1996"


Journal ArticleDOI
TL;DR: In this article, the microstructure of ball-milled iron powder has been investigated by high-resolution X-ray line profile analysis, and it has been shown that strain broadening, even in these nanoscale small-grain particles, is caused by the presence of dislocations.

179 citations


Journal ArticleDOI
TL;DR: In this article, the authors addressed specific densification issues related to the nanocrystalline nature of the consolidating particulates. But, they focused on processes that have demonstrated the capability to form dense specimens with retention of fine grain sizes, and the experimental aspects cover powder compressibility and differential shrinkage, heating rate and pressure effects.

165 citations


Journal ArticleDOI
TL;DR: In this paper, a nanosized TiO2 thin film with high surface-to-volume ratio was used as a gas sensor for monitoring exhaust gases of engines, which can detect 20 ppm of NO2 at a temperature suitable for monitoring of exhaust gases.

116 citations


Journal ArticleDOI
TL;DR: Nanocrystalline graphite with a crystallite size of about 2 nm is formed after 8 h of ball milling as mentioned in this paper. But this graphite is relatively stable against heating when compared with some nanocrystine metals.

112 citations


Journal ArticleDOI
TL;DR: In this article, the in-situ synthesis of nanosized crystalline SiC powders at room temperature through high energy ball milling of elemental silicon and carbon mixtures was investigated.

105 citations


Journal ArticleDOI
TL;DR: The grain size of the powder compacts, determined using transmission electron microscopy, was found to be 11 ± 5 nm as mentioned in this paper. But the grain size was not maintained when the heat treatment temperature was increased to 1373 K, or over 75% of the melting point of Fe.

75 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed full-density bulk nanocomposites for the immiscible Cu-Fe system through a powder metallurgy route, which were then decomposed into two-phase domains of various volume fractions during the hot consolidation process.

75 citations


Journal ArticleDOI
TL;DR: In this paper, the results of an investigation aiming at synthesizing nanocrystalline α-alumina using the auto-ignition processing technique were reported, and the resulting powders obtained from various ratios of the oxidizer and fuel.

74 citations


Journal ArticleDOI
TL;DR: In this article, a new preparation process for nanostructured alloys utilizing co-evaporation in a continuous gas flow has been developed, where inert gas is injected into a preparation chamber through a nozzle in order to establish a convectional flow that carries crystallites of one element above an evaporation source of a second element so that the atoms of the second source condense at the crystallite's surfaces in the form of a thin coating.

71 citations


Journal ArticleDOI
R. Nitsche, M. Rodewald, Ganesh Skandan1, Hartmut Fuess, Horst Hahn 
TL;DR: In this article, high-resolution micrographs of a single nanosized ZrO2 particle have been used to demonstrate the martensitic phase transition character of zirconia powders.

69 citations


Journal ArticleDOI
TL;DR: In this article, three different burners were used to obtain a wide range of flame processing conditions (different time-temperature histories) to study the formation of nanophase titania particles.

Journal ArticleDOI
TL;DR: In this paper, examples of new nanocrystalline catalytic and electrocatalytic materials are presented in this paper to demonstrate their impressive potential, and they offer the possibilities to design crystalline surface nearly on an atomic scale, and then tailor a specific microstructure for catalytic materials to achieve improvements on a given catalytic process.

Journal ArticleDOI
TL;DR: In this paper, the evolution of magnetic properties and structure with annealing temperature of glass-coated microwires with composition Fe73.5B22.5 − xSixCu1Nb3 (x = 11.5, 13.5 and 16.5) has been studied for samples with diameter of metallic nucleus ranging from 4 to 22 μm and fixed total diameter of around 26 μm.

Journal ArticleDOI
TL;DR: In this paper, high stable, wurtzite quantum sized ZnO colloids encapsulated in polymers have been synthesized and shown to exhibit excitonic as well as trapped fluorescence.

Journal ArticleDOI
TL;DR: In this article, the effects of thermal exposure accompanying the ball milling process were investigated and the observed disappearance of the X-ray peaks of constituent elements was associated with lower atomic scattering factor and grain refinement rather than the actual dissolution of the element.

Journal ArticleDOI
TL;DR: In this article, the average particle size of these colloids was found to depend on the amount of precursor and polyvinyl pyrrolidone (PVP) added.

Journal ArticleDOI
TL;DR: In this article, high-resolution and analytical electron microscopy has been used to analyze morphological features in consolidated specimens of nanostructured tungsten carbide-cobalt cermet materials.

Journal ArticleDOI
TL;DR: In this paper, two types of WC-Co powders, nanometer particle size and micron particle size, were studied by means of dilatometry, and the experiments showed that the sintering behavior of the nanocrystalline specimens is different from that of the micron grain-size specimen.

Journal ArticleDOI
TL;DR: In this paper, the ball milling of FeNiNi36 was performed by the ball-milling process and XRD studies revealed that the alloy was crystallized in a stable FCC phase.

Journal ArticleDOI
TL;DR: In this article, a nanocomposite Al 2 O 3 Al material has been prepared by consolidation of nanocrystalline aluminum particles which have been passivated with an alumina overlayer prior to the compaction step.

Journal ArticleDOI
Nian X. Sun, K. Zhang, X.H. Zhang, X.D. Liu1, Kathy Lu1 
TL;DR: In this paper, a nanocrystalline (NC) fcc FeZr 2 intermetallic compound was formed by completely crystallizing the melt-spun amorphous Fe 33 Zr 67 alloy ribbons.

Journal ArticleDOI
M.Y. Gamarnik1
TL;DR: In this article, the authors established boundaries of stability regions of diamond and graphite at low pressure and various temperatures by modeling and computation of free energies of the crystal phases, which indicated that diamond is the stable modification of carbon, and that graphite is the metastable one at small particle sizes.

Journal ArticleDOI
TL;DR: In this article, a nanoscaled Al2O3-powders are employed for diffusion bonding of alumina ceramics, and the results show that the hardness of the joint depends strongly on the porosity content and/or grain size.

Journal ArticleDOI
TL;DR: In this article, a nonequilibrium structure consisting of nanoscale amorphous particles surrounded by fcc-Al phase was found to form in an Al94V4Fe2 alloy rapidly solidified at the condition of circumferential velocity of 40 m/s and ejection temperature of molten alloy between 1273 and 1423 K.

Journal ArticleDOI
TL;DR: In this article, the analysis of integral widths based on peak by peak fitting was performed to analyze the observed anisotropic size effect of prismatic shaped titanium oxide crystals, approximately 30 by 15 by 15 nanometers in size.

Journal ArticleDOI
TL;DR: In this paper, the surface properties of wear-induced hardening of steel railroad tracks were investigated using ball-milled powder samples, which can be used as a model system for characterizing the chemical, mechanical (hardness, Young's modulus, coefficient of friction) and thermal properties of the wear induced nanophase surfaces.

Journal ArticleDOI
TL;DR: The role of Fe and Cr on the disordering behavior of mechanically alloyed nanocrystalline NiAl has been investigated in this paper, where the results of milling with WC media show that NiAl is only partially ordered in the as-milled stoichiometric composition.

Journal ArticleDOI
TL;DR: In this paper, x-ray diffraction powder patterns of a random nanocrystalline material containing two atomic species were calculated by evaluation of the Debye function, atoms of different types were positioned to produce stoichiometric compound, CsCl, and grain boundary segregation in copper-iron alloys.

Journal ArticleDOI
TL;DR: The reaction of a 25 mol% Fe2O3-SiO2 (hematite-amorphous silica) powder mixture during high energy ball milling in both closed and open containers has been studied by x-ray diffraction and Mossbauer spectroscopy.

Journal ArticleDOI
TL;DR: In this paper, the properties of nanophase microstructures in nanostructured zirconia and yttria-stabilized nanostructure were investigated.