Abdul Faheem Khan - Profile on Academia.edu (original) (raw)

Papers by Abdul Faheem Khan

Precipitation Hardening in (α+ߩ and Lead-Tin Brasses

Journal of Applied Sciences, 2001

Abstract: Commercially available two different compositions of(a+β) and lead-tin-brasses were sol... more Abstract: Commercially available two different compositions of(a+β) and lead-tin-brasses were solution treated at 815°C for ½ hr and aged at 400 and 500°C for ½ and 1 hr. The tensile test data were analyzed to find the UTS (ultimate tensile strength), elastic modulus, ...

Applied Surface Science, 2010

Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) sub... more Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) substrates by RF magnetron sputtering using nickel and ITO (In-Sn, 90-10%) targets. The post-deposition annealing has been performed for Ni/ITO films in air. The effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. We found the appearance of (6 2 2) peak in addition to (4 0 0) and (2 2 2) major peaks, which indicates an enhancement of the film crystallinity at high temperature annealing of 650°C. The samples show higher transmittance of more than 90% at 470 nm after annealing which is suitable for blue light emitting diode (LED) application. The optical energy bandgap is shifted from 3.51 to 3.65 eV for the Ni/ITO film after annealing at 650°C. In addition, increasing the annealing temperature improves the film electrical properties. The resistivity value decreases from 3.77 Â 10 À5 X cm to 1.09 Â 10 À6 X cm upon increasing annealing temperature.

Applied Surface Science, 2010

Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) sub... more Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) substrates by RF magnetron sputtering using nickel and ITO (In-Sn, 90-10%) targets. The post-deposition annealing has been performed for Ni/ITO films in air. The effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. We found the appearance of (6 2 2) peak in addition to (4 0 0) and (2 2 2) major peaks, which indicates an enhancement of the film crystallinity at high temperature annealing of 650°C. The samples show higher transmittance of more than 90% at 470 nm after annealing which is suitable for blue light emitting diode (LED) application. The optical energy bandgap is shifted from 3.51 to 3.65 eV for the Ni/ITO film after annealing at 650°C. In addition, increasing the annealing temperature improves the film electrical properties. The resistivity value decreases from 3.77 Â 10 À5 X cm to 1.09 Â 10 À6 X cm upon increasing annealing temperature.

Quenched-in Lattice Defects in Pure Aluminium

Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temp... more Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temperature coefficient of the resistance. This increase in resistivity of metals is due to more thermal agitation of atoms and structural disorder to diffract and scatter the electrons at high ...

Journal of Applied Sciences, 2001

In this work, we draw attention to determination of heat-treatment effects on mechanical properti... more In this work, we draw attention to determination of heat-treatment effects on mechanical properties of atmospheric plasma sprayed (APS) Fe x B coatings on aluminum substrates by micro-indentation technique. With this regard, iron boride powders of Fe-18.8B-0.2C-0.5Si-0.8Al (wt.%) were deposited onto Al substrates by APS in order to improve the mechanical properties of Al surface. As-sprayed coatings are composed of mainly Fe x B and iron matrix supersaturated with boron owing to the rapid solidification of molten droplets flattened on a substrate. It was observed that APS coatings exhibited characteristic wavy layered structure having porosity, inclusions, and semimelted particles. The postfurnace treatment of APS coatings was carried out at temperatures ranged from 450 to 550 • C in an argon atmosphere. The post-treatment applied for APS deposits led to increase in hardness of 40% without showing cracks. Furthermore, micro-mechanical properties of Fe x B coatings were examined by Shimadzu Dynamic Ultra-Microhardness Tester for estimating Young's modulus and hardness due to load-unload sensing analysis by applying different loads such as 160, 320, and 640 mN to determine load and indentation depth dependency of APS Fe x B on Al substrate for each samples, in details.

Applied Surface Science, 2010

Materials Chemistry and Physics, 2004

Radio frequency (rf)-sputtered indium tin oxide (ITO) thin films were characterized by studying t... more Radio frequency (rf)-sputtered indium tin oxide (ITO) thin films were characterized by studying their structure, electrical and optical properties. Before characterization the ITO films were annealed at different temperatures ranging from 100 to 500 • C for a constant time of 15 min in air. The ITO thin films were observed to possess a cubic structure with (1 1 0) texture, an electrical resistivity in the range (5-11.5) × 10 −4 cm at different annealing temperatures. The rise in resistivity due to annealing was associated with the filling up of oxygen vacancies, and the fall in resistivity was attributed to the rearrangement and removal of defects as well as improvement in the crystalline nature of these films. The optical bandgap energy was found to be ≈4.0 eV. The ITO thin films were of comparable quality to those deposited elsewhere for use as window layers in solar cells.

Nanostructured multilayer TiO 2–Ge films with quantum confinement effects for photovoltaic applications

Journal of Colloid and Interface Science, 2010

Multilayer TiO(2)-Ge thin films have been deposited using electron beam evaporation and resistive... more Multilayer TiO(2)-Ge thin films have been deposited using electron beam evaporation and resistive heating. The thickness of the TiO(2) layers is 20 nm, while the thickness of the Ge layers varies from 2 to 20 nm with a step of 2 nm away from the substrate. These films were characterized by studying their optical, electrical, and structural properties. The films were annealed at various temperatures up to 500 degrees C for 2 h. The films are amorphous up to an annealing temperature of 400 degrees C, although Raman spectra suggest short-range ordering (and adjustments). The films annealed at 450 and 500 degrees C exhibit X-ray reflections of Ge and anatase TiO(2). Illumination in sunlight increases the conductivity of the as-deposited and annealed films. The band gap of the amorphous films changes from 1.27 to 1.41 eV up to 400 degrees C; the major contribution is possibly through direct transition. Two band gap regimes are clearly seen after 450 and 500 degrees C, which have been assigned to an indirect band gap at about 1.2 eV and a direct band gap at about 1.8 eV. Conductivity of the multilayer films has been higher than that of pure Ge film. The conductivity increases with annealing temperature with abrupt increase at about 380 degrees C. The results imply that the TiO(2)-Ge multilayer films may be employed as heterojunctions with tunable band gap energy as related to quantum confinement effects.

In this work, we draw attention to determination of heat-treatment effects on mechanical properti... more In this work, we draw attention to determination of heat-treatment effects on mechanical properties of atmospheric plasma sprayed (APS) Fe x B coatings on aluminum substrates by micro-indentation technique. With this regard, iron boride powders of Fe-18.8B-0.2C-0.5Si-0.8Al (wt.%) were deposited onto Al substrates by APS in order to improve the mechanical properties of Al surface. As-sprayed coatings are composed of mainly Fe x B and iron matrix supersaturated with boron owing to the rapid solidification of molten droplets flattened on a substrate. It was observed that APS coatings exhibited characteristic wavy layered structure having porosity, inclusions, and semimelted particles. The postfurnace treatment of APS coatings was carried out at temperatures ranged from 450 to 550 • C in an argon atmosphere. The post-treatment applied for APS deposits led to increase in hardness of 40% without showing cracks. Furthermore, micro-mechanical properties of Fe x B coatings were examined by Shimadzu Dynamic Ultra-Microhardness Tester for estimating Young's modulus and hardness due to load-unload sensing analysis by applying different loads such as 160, 320, and 640 mN to determine load and indentation depth dependency of APS Fe x B on Al substrate for each samples, in details.

Materials & Design, 2003

S 0 2 6 1 -3 0 6 9 Ž 0 2 . 0 0 1 0 6 -1 Quenched-in lattice defects in pure aluminium (99.999%)

Effect of substrate on processing of multigun sputter deposited, near-stoichiometric Ni 2MnGa thin films

Thin Solid Films, 2010

Near-stoichiometric Ni2MnGa thin films were sputter deposited with a multi-gun sputter deposition... more Near-stoichiometric Ni2MnGa thin films were sputter deposited with a multi-gun sputter deposition system onto sapphire, silicon dioxide and silicon substrates and exposed to heat treatments in vacuum. The multi-gun setup was proven to be feasible for switching compositions quickly and reliably. Using chemical, morphological, magnetic and structural characterisation methods the effects of the different substrates on the Ni2MnGa film properties

Journal of Applied Sciences, 2001

Applied Surface Science, 2009

Materials Chemistry and Physics, 2003

Specimens of Ni-25 at.% Cr alloy were heated for 60 min at different temperatures ranging from 60... more Specimens of Ni-25 at.% Cr alloy were heated for 60 min at different temperatures ranging from 600 to 1000 • C, quenched in brine and then aged isochronally at temperatures ranging from 150 to 650 • C for 30 min and aged isothermally at 70 and 400 • C for various times. It is observed that the resistivity rises up to a saturation value on aging isothermally at 400 • C. The initial increase in resistivity during aging may be described by the clustering of solute atoms at the early stages of precipitation that may transform to stable precipitates for very long aging times. The sudden variation in resistivity with rising temperature may be attributed to the onset of the CrNi 3 ordering reaction.

Quenched-in Lattice Defects in Pure Aluminium

Journal of Applied Sciences, 2001

Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temp... more Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temperature coefficient of the resistance. This increase in resistivity of metals is due to more thermal agitation of atoms and structural disorder to diffract and scatter the electrons at high ...

Applied Surface Science, 2009

Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO 2 Thin Films

Chinese Physics Letters, 2009

Page 1. Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO2 Thin Films This ar... more Page 1. Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO2 Thin Films This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2009 Chinese Phys. Lett. 26 077803 (http://iopscience.iop.org/0256-307X/26/7/077803) ...

Precipitation Hardening in (alpha+ß) and Lead-Tin Brasses

Precipitation Hardening in (α+ߩ and Lead-Tin Brasses

Journal of Applied Sciences, 2001

Abstract: Commercially available two different compositions of(a+β) and lead-tin-brasses were sol... more Abstract: Commercially available two different compositions of(a+β) and lead-tin-brasses were solution treated at 815°C for ½ hr and aged at 400 and 500°C for ½ and 1 hr. The tensile test data were analyzed to find the UTS (ultimate tensile strength), elastic modulus, ...

Applied Surface Science, 2010

Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) sub... more Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) substrates by RF magnetron sputtering using nickel and ITO (In-Sn, 90-10%) targets. The post-deposition annealing has been performed for Ni/ITO films in air. The effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. We found the appearance of (6 2 2) peak in addition to (4 0 0) and (2 2 2) major peaks, which indicates an enhancement of the film crystallinity at high temperature annealing of 650°C. The samples show higher transmittance of more than 90% at 470 nm after annealing which is suitable for blue light emitting diode (LED) application. The optical energy bandgap is shifted from 3.51 to 3.65 eV for the Ni/ITO film after annealing at 650°C. In addition, increasing the annealing temperature improves the film electrical properties. The resistivity value decreases from 3.77 Â 10 À5 X cm to 1.09 Â 10 À6 X cm upon increasing annealing temperature.

Applied Surface Science, 2010

Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) sub... more Nickel (Ni)/indium tin oxide (ITO) nanostructures were deposited on glass and silicon (1 1 1) substrates by RF magnetron sputtering using nickel and ITO (In-Sn, 90-10%) targets. The post-deposition annealing has been performed for Ni/ITO films in air. The effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. We found the appearance of (6 2 2) peak in addition to (4 0 0) and (2 2 2) major peaks, which indicates an enhancement of the film crystallinity at high temperature annealing of 650°C. The samples show higher transmittance of more than 90% at 470 nm after annealing which is suitable for blue light emitting diode (LED) application. The optical energy bandgap is shifted from 3.51 to 3.65 eV for the Ni/ITO film after annealing at 650°C. In addition, increasing the annealing temperature improves the film electrical properties. The resistivity value decreases from 3.77 Â 10 À5 X cm to 1.09 Â 10 À6 X cm upon increasing annealing temperature.

Quenched-in Lattice Defects in Pure Aluminium

Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temp... more Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temperature coefficient of the resistance. This increase in resistivity of metals is due to more thermal agitation of atoms and structural disorder to diffract and scatter the electrons at high ...

Journal of Applied Sciences, 2001

In this work, we draw attention to determination of heat-treatment effects on mechanical properti... more In this work, we draw attention to determination of heat-treatment effects on mechanical properties of atmospheric plasma sprayed (APS) Fe x B coatings on aluminum substrates by micro-indentation technique. With this regard, iron boride powders of Fe-18.8B-0.2C-0.5Si-0.8Al (wt.%) were deposited onto Al substrates by APS in order to improve the mechanical properties of Al surface. As-sprayed coatings are composed of mainly Fe x B and iron matrix supersaturated with boron owing to the rapid solidification of molten droplets flattened on a substrate. It was observed that APS coatings exhibited characteristic wavy layered structure having porosity, inclusions, and semimelted particles. The postfurnace treatment of APS coatings was carried out at temperatures ranged from 450 to 550 • C in an argon atmosphere. The post-treatment applied for APS deposits led to increase in hardness of 40% without showing cracks. Furthermore, micro-mechanical properties of Fe x B coatings were examined by Shimadzu Dynamic Ultra-Microhardness Tester for estimating Young's modulus and hardness due to load-unload sensing analysis by applying different loads such as 160, 320, and 640 mN to determine load and indentation depth dependency of APS Fe x B on Al substrate for each samples, in details.

Applied Surface Science, 2010

Materials Chemistry and Physics, 2004

Radio frequency (rf)-sputtered indium tin oxide (ITO) thin films were characterized by studying t... more Radio frequency (rf)-sputtered indium tin oxide (ITO) thin films were characterized by studying their structure, electrical and optical properties. Before characterization the ITO films were annealed at different temperatures ranging from 100 to 500 • C for a constant time of 15 min in air. The ITO thin films were observed to possess a cubic structure with (1 1 0) texture, an electrical resistivity in the range (5-11.5) × 10 −4 cm at different annealing temperatures. The rise in resistivity due to annealing was associated with the filling up of oxygen vacancies, and the fall in resistivity was attributed to the rearrangement and removal of defects as well as improvement in the crystalline nature of these films. The optical bandgap energy was found to be ≈4.0 eV. The ITO thin films were of comparable quality to those deposited elsewhere for use as window layers in solar cells.

Nanostructured multilayer TiO 2–Ge films with quantum confinement effects for photovoltaic applications

Journal of Colloid and Interface Science, 2010

Multilayer TiO(2)-Ge thin films have been deposited using electron beam evaporation and resistive... more Multilayer TiO(2)-Ge thin films have been deposited using electron beam evaporation and resistive heating. The thickness of the TiO(2) layers is 20 nm, while the thickness of the Ge layers varies from 2 to 20 nm with a step of 2 nm away from the substrate. These films were characterized by studying their optical, electrical, and structural properties. The films were annealed at various temperatures up to 500 degrees C for 2 h. The films are amorphous up to an annealing temperature of 400 degrees C, although Raman spectra suggest short-range ordering (and adjustments). The films annealed at 450 and 500 degrees C exhibit X-ray reflections of Ge and anatase TiO(2). Illumination in sunlight increases the conductivity of the as-deposited and annealed films. The band gap of the amorphous films changes from 1.27 to 1.41 eV up to 400 degrees C; the major contribution is possibly through direct transition. Two band gap regimes are clearly seen after 450 and 500 degrees C, which have been assigned to an indirect band gap at about 1.2 eV and a direct band gap at about 1.8 eV. Conductivity of the multilayer films has been higher than that of pure Ge film. The conductivity increases with annealing temperature with abrupt increase at about 380 degrees C. The results imply that the TiO(2)-Ge multilayer films may be employed as heterojunctions with tunable band gap energy as related to quantum confinement effects.

In this work, we draw attention to determination of heat-treatment effects on mechanical properti... more In this work, we draw attention to determination of heat-treatment effects on mechanical properties of atmospheric plasma sprayed (APS) Fe x B coatings on aluminum substrates by micro-indentation technique. With this regard, iron boride powders of Fe-18.8B-0.2C-0.5Si-0.8Al (wt.%) were deposited onto Al substrates by APS in order to improve the mechanical properties of Al surface. As-sprayed coatings are composed of mainly Fe x B and iron matrix supersaturated with boron owing to the rapid solidification of molten droplets flattened on a substrate. It was observed that APS coatings exhibited characteristic wavy layered structure having porosity, inclusions, and semimelted particles. The postfurnace treatment of APS coatings was carried out at temperatures ranged from 450 to 550 • C in an argon atmosphere. The post-treatment applied for APS deposits led to increase in hardness of 40% without showing cracks. Furthermore, micro-mechanical properties of Fe x B coatings were examined by Shimadzu Dynamic Ultra-Microhardness Tester for estimating Young's modulus and hardness due to load-unload sensing analysis by applying different loads such as 160, 320, and 640 mN to determine load and indentation depth dependency of APS Fe x B on Al substrate for each samples, in details.

Materials & Design, 2003

S 0 2 6 1 -3 0 6 9 Ž 0 2 . 0 0 1 0 6 -1 Quenched-in lattice defects in pure aluminium (99.999%)

Effect of substrate on processing of multigun sputter deposited, near-stoichiometric Ni 2MnGa thin films

Thin Solid Films, 2010

Near-stoichiometric Ni2MnGa thin films were sputter deposited with a multi-gun sputter deposition... more Near-stoichiometric Ni2MnGa thin films were sputter deposited with a multi-gun sputter deposition system onto sapphire, silicon dioxide and silicon substrates and exposed to heat treatments in vacuum. The multi-gun setup was proven to be feasible for switching compositions quickly and reliably. Using chemical, morphological, magnetic and structural characterisation methods the effects of the different substrates on the Ni2MnGa film properties

Journal of Applied Sciences, 2001

Applied Surface Science, 2009

Materials Chemistry and Physics, 2003

Specimens of Ni-25 at.% Cr alloy were heated for 60 min at different temperatures ranging from 60... more Specimens of Ni-25 at.% Cr alloy were heated for 60 min at different temperatures ranging from 600 to 1000 • C, quenched in brine and then aged isochronally at temperatures ranging from 150 to 650 • C for 30 min and aged isothermally at 70 and 400 • C for various times. It is observed that the resistivity rises up to a saturation value on aging isothermally at 400 • C. The initial increase in resistivity during aging may be described by the clustering of solute atoms at the early stages of precipitation that may transform to stable precipitates for very long aging times. The sudden variation in resistivity with rising temperature may be attributed to the onset of the CrNi 3 ordering reaction.

Quenched-in Lattice Defects in Pure Aluminium

Journal of Applied Sciences, 2001

Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temp... more Rana etal.: Quenched-in Lattice Defects in Pure Aluminium and T(K) respectively and a is the temperature coefficient of the resistance. This increase in resistivity of metals is due to more thermal agitation of atoms and structural disorder to diffract and scatter the electrons at high ...

Applied Surface Science, 2009

Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO 2 Thin Films

Chinese Physics Letters, 2009

Page 1. Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO2 Thin Films This ar... more Page 1. Optical Characterization of rf-Magnetron Sputtered Nanostructured SnO2 Thin Films This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2009 Chinese Phys. Lett. 26 077803 (http://iopscience.iop.org/0256-307X/26/7/077803) ...

Precipitation Hardening in (alpha+ß) and Lead-Tin Brasses