V.K. Sachdev; S.K. Sharma; S. Bhattacharya; K. Patel; N.C. Mehra; V. Gupta; R.P. Tandon
Abstract
Growing electromagnetic pollution caused by the rapid proliferation of sophisticated electronic devices has increasingly invited concerns. Cement based composites are commercially established in constructions, also capable of electromagnetic interference shielding besides other multifunctional utilities. ...
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Growing electromagnetic pollution caused by the rapid proliferation of sophisticated electronic devices has increasingly invited concerns. Cement based composites are commercially established in constructions, also capable of electromagnetic interference shielding besides other multifunctional utilities. Cement matrix a key ingredient in mixes is considered to be the best adhesive that holds together the aggregates. In this work these composites filled with conductive graphite particles were prepared using dry tumble mixing modus operandi followed by compression and subsequent curing with water. Prolong tumble mixing ensures even dispersion of constituents while compression develops a stronger bond to the aggregates besides patterning of graphite particles in cement matrix. This patterning of conductive graphite particles is vital for producing enhanced electrical and dielectric properties. Effects of increasing graphite concentration on electrical properties and electromagnetic interference shielding effectiveness in X band were investigated. The cement with 20 wt% graphite shows an enormous electrical conductivity 2.74 × 10 -1
M. Chowdhury; S.K. Sharma; R.J. Chaudhary
Abstract
SnO2/Fe2O3 composite thin films were deposited on quartz substrates at various oxygen partial pressures with a substrate temperature of 750 °C by pulsed laser deposition. The structural and optical properties of the deposited films were studied by X-ray diffraction (XRD), Atomic force microscopy ...
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SnO2/Fe2O3 composite thin films were deposited on quartz substrates at various oxygen partial pressures with a substrate temperature of 750 °C by pulsed laser deposition. The structural and optical properties of the deposited films were studied by X-ray diffraction (XRD), Atomic force microscopy (AFM), UV–visible spectroscopy and Photoluminescence. X-ray diffraction analysis revealed the formation of mixed phases (tetragonal SnO2 and hexagonal α-Fe2O3) at lower oxygen partial pressure (0.1 mTorr) and only tetragonal phase at higher oxygen partial pressures (50-250 mTorr). Atomic force microscopy studies show the dense and uniform distribution of composite films. The average RMS roughness of the films increases with increasing oxygen partial pressure. The bandgap was found varying between 3.55 and 3.85 eV for different oxygen pressures. A strong broad blue emission band was observed for all the oxygen partial pressures. The origin of the blue emission in the composite film is discussed with the help of vacancy creation. A correlation between oxygen partial pressure and the properties of SnO2/Fe2O3 .