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We have investigated the phase changes in CdTiO3 nanofibers as the annealing temperature of nanofibers was increased from 600 to 1200 °C. The nanofibers annealed at 600 °C were ilmenite with a very small amount of CdO. Upon annealing at 950 °C, CdO was completely removed. Annealing at 1000 °C yielded pure perovskite nanofibers, and at temperatures above 1100 °C rutile TiO2 nanofibers were obtained. Brunauer-Emmett-Teller (BET) analysis showed that with increase in annealing temperature the surface area of nanofibers was decreased. The nanofibers annealed at 600 °C have the higher surface area of ∼9.41 m(2)/g. Then oxygen sensors using CdTiO3 nanofibers annealed at 600 °C (ilmenite) and 1000 °C (perovskite) were fabricated. The sensitivity of the ilmenite nanofibers sensor was 2 times than that of the perovskite nanofibers sensor. The response and recovery times were 120 and 23 s, respectively, for the ilmenite nanofibers sensor, whereas response and recovery times were 156 and 50 s, respectively, for the perovskite nanofibers sensor. Better oxygen characteristics of ilmenite nanofibers are attributed to their large surface area and porosity. Therefore, we believe that ilmenite CdTiO3 nanofibers are potential candidates to develop practical oxygen sensors.

We present the synthesis of crystalline MoS2 nanoflakes through self-exfoliation in a simple solid state reaction at temperature ∼650 °C. X-ray diffraction and Transmission Electron Microscope analysis indicate the formation of pure hexagonal phase MoS2 nanoflakes. Impedance and modulus plane plots from 20 Hz to 2 MHz show two relaxations associated with bulk and interface phases at temperatures from 180 K to 280 K. The conductivity obeys Mott's 2D variable-range hopping phenomenon and density of localized states ∼3.42 × 1019 eV-1 cm−3 is extracted.

Lightweight metal matrix composites are synthesized from elemental powder mixtures of aluminum and magnesium using pressure-assisted reactive sintering. The effect of the reaction between aluminum and magnesium on the microstructure and mechanical properties of the composites due to the formation of β-Al3Mg2 and γ-Al12Mg17 intermetallics is investigated. The formation of the intermetallic compounds progressively consumes aluminum and magnesium and induces strengthening of the composites: the yield and compressive strengths increase with the increase of the content of intermetallic reinforcement at the expense of the plastic deformation. The yield strength of the composites follows the iso-stress model when the data are plotted as a function of the intermetallic content.

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