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Papers by Mohamed Radwan

Research paper thumbnail of Formation and evolution of quasi-aligned AIN nanowhiskers by combustion synthesis

Journal of Alloys and Compounds, 2009

Research paper thumbnail of Functionally Graded Material Shape and Method for Producing Such a Shape

Research paper thumbnail of Self-Propagating High-temperature Synthesis of AIN Nanostructures and Their Sintering Properties

Transactions of Jwri, Dec 1, 2006

Research paper thumbnail of Combustion Synthesis and Sintering of �-Sialon Ceramics (z = 2)

Journal of the Society of Materials Science Japan, 2008

Research paper thumbnail of Synthesis of Si2 N2 O Ceramics from Desert Sand

Ceramic Transactions Series, 2012

Research paper thumbnail of Growth of Quasi-Aligned AIN Nanofibers by Nitriding Combustion Synthesis

Research paper thumbnail of New synthesis route for Si2N2O ceramics based on desert sand

Journal of the European Ceramic Society, 2003

A new approach for synthesis and sintering of silicon oxynitride starting from a unique natural r... more A new approach for synthesis and sintering of silicon oxynitride starting from a unique natural raw material, desert sand is described. The sand in a mixture with silicon metal is combusted under pressurized nitrogen gas into pure silicon oxynitride powder. Then, this powder is densified in the presence of 5 wt.% calcia-alumina mixture to a compact with about 99% of

Research paper thumbnail of Nanostructured Ni–AlN composite coatings

Surface and Coatings Technology, 2006

Electrodeposited Ni composite coatings embedded with AlN particles were deposited on mild steel s... more Electrodeposited Ni composite coatings embedded with AlN particles were deposited on mild steel substrates. AlN whiskers of 40-150 nm size were successfully prepared by nitriding method. Coatings were produced from Ni Watt's bath and the optimum conditions of plating process were determined. The wear resistance and friction coefficients of Ni-AlN composite coatings containing various amounts of AlN have been studied. The corrosion rates of composite coatings were measured in 1 M HCl solution. Surface morphology of the coatings was analyzed by using a scanning electron microscope (SEM). Thermal stability of the pure Ni and composite coatings were studied at 900-1100°C. The thermal expansion coefficients of the coatings were investigated in the temperature range of 100-650°C. The results referred that increasing the incorporation rate of AlN particles leads to an increase in both of the hardness and friction coefficients of the films. The composite coatings containing 41 wt.% of AlN exhibited high resistance against wear and corrosion. The addition of low expansion AlN particles restricted the expansion of matrix through interfaces.

Research paper thumbnail of A modified direct nitridation method for formation of nano-AlN whiskers

Journal of Materials Processing Technology, 2007

The direct nitridation of metallic aluminium under isothermal conditions was studied. Aluminium w... more The direct nitridation of metallic aluminium under isothermal conditions was studied. Aluminium with 99% purity in both compacted and loose powder forms was nitrided in nitrogen gas flow at the temperature range of 600-1000 • C. Compacted Al samples showed very low nitridation tendency till 1000 • C. High nitridation conversions were achieved in the powder Al samples where the nitridation started after the melting point of Al and the conversion was greatly improved with increasing the nitridation temperature. The nitridation time and the nitrogen flow rate were found not to be critical for improving the conversion extent. The addition of pre-synthesized AlN powder to the starting Al powder retarded the nitridation conversion whereas the addition of NH 4 Cl powder enhanced the AlN yield to near completeness. It is found that the addition of NH 4 Cl promotes the growth of AlN whiskers.

Research paper thumbnail of Reduction behavior of barium hexaferrite into metallic iron nanocrystallites

Journal of Magnetism and Magnetic Materials, 2007

... Magnetic measurements show diluted magnetic properties for the formed metallic iron, whereas ... more ... Magnetic measurements show diluted magnetic properties for the formed metallic iron, whereas coercivity values were in the range 14.1–55 Oe and saturation magnetization varied from 24.79 to 36.15 emu/g. These values have been ascribed to the formation and growth of ...

Research paper thumbnail of Synthesis of Si 2 N 2 O-SiC composites from desert sand

Transactions of the JWRI, 2002

Trans. JWRI, Vol.31, (2002), No.l 1UU £ 80 - Si2N20 *_^^ ^**"*#^^ a s. о 60 - ^\^ . и **>... more Trans. JWRI, Vol.31, (2002), No.l 1UU £ 80 - Si2N20 *_^^ ^**"*#^^ a s. о 60 - ^\^ . и **>^ ^0/í****' & j><\^ 40 - ^*^^ ^^* Л ^t//>^^ Ы) à^^^ 20 - SiC^-"^^ 0 - ' 1 ' 1 ' 1 ' 1 ' 0.2 0.4 0.6 Y (mole) 0.8 Fig. 3 Change of composition in the synthesized Si2N20-SiC composites. . 99 - ...

Research paper thumbnail of Formation and evolution of quasi-aligned AIN nanowhiskers by combustion synthesis

Journal of Alloys and Compounds, 2009

Research paper thumbnail of Functionally Graded Material Shape and Method for Producing Such a Shape

Research paper thumbnail of Self-Propagating High-temperature Synthesis of AIN Nanostructures and Their Sintering Properties

Transactions of Jwri, Dec 1, 2006

Research paper thumbnail of Combustion Synthesis and Sintering of �-Sialon Ceramics (z = 2)

Journal of the Society of Materials Science Japan, 2008

Research paper thumbnail of Synthesis of Si2 N2 O Ceramics from Desert Sand

Ceramic Transactions Series, 2012

Research paper thumbnail of Growth of Quasi-Aligned AIN Nanofibers by Nitriding Combustion Synthesis

Research paper thumbnail of New synthesis route for Si2N2O ceramics based on desert sand

Journal of the European Ceramic Society, 2003

A new approach for synthesis and sintering of silicon oxynitride starting from a unique natural r... more A new approach for synthesis and sintering of silicon oxynitride starting from a unique natural raw material, desert sand is described. The sand in a mixture with silicon metal is combusted under pressurized nitrogen gas into pure silicon oxynitride powder. Then, this powder is densified in the presence of 5 wt.% calcia-alumina mixture to a compact with about 99% of

Research paper thumbnail of Nanostructured Ni–AlN composite coatings

Surface and Coatings Technology, 2006

Electrodeposited Ni composite coatings embedded with AlN particles were deposited on mild steel s... more Electrodeposited Ni composite coatings embedded with AlN particles were deposited on mild steel substrates. AlN whiskers of 40-150 nm size were successfully prepared by nitriding method. Coatings were produced from Ni Watt's bath and the optimum conditions of plating process were determined. The wear resistance and friction coefficients of Ni-AlN composite coatings containing various amounts of AlN have been studied. The corrosion rates of composite coatings were measured in 1 M HCl solution. Surface morphology of the coatings was analyzed by using a scanning electron microscope (SEM). Thermal stability of the pure Ni and composite coatings were studied at 900-1100°C. The thermal expansion coefficients of the coatings were investigated in the temperature range of 100-650°C. The results referred that increasing the incorporation rate of AlN particles leads to an increase in both of the hardness and friction coefficients of the films. The composite coatings containing 41 wt.% of AlN exhibited high resistance against wear and corrosion. The addition of low expansion AlN particles restricted the expansion of matrix through interfaces.

Research paper thumbnail of A modified direct nitridation method for formation of nano-AlN whiskers

Journal of Materials Processing Technology, 2007

The direct nitridation of metallic aluminium under isothermal conditions was studied. Aluminium w... more The direct nitridation of metallic aluminium under isothermal conditions was studied. Aluminium with 99% purity in both compacted and loose powder forms was nitrided in nitrogen gas flow at the temperature range of 600-1000 • C. Compacted Al samples showed very low nitridation tendency till 1000 • C. High nitridation conversions were achieved in the powder Al samples where the nitridation started after the melting point of Al and the conversion was greatly improved with increasing the nitridation temperature. The nitridation time and the nitrogen flow rate were found not to be critical for improving the conversion extent. The addition of pre-synthesized AlN powder to the starting Al powder retarded the nitridation conversion whereas the addition of NH 4 Cl powder enhanced the AlN yield to near completeness. It is found that the addition of NH 4 Cl promotes the growth of AlN whiskers.

Research paper thumbnail of Reduction behavior of barium hexaferrite into metallic iron nanocrystallites

Journal of Magnetism and Magnetic Materials, 2007

... Magnetic measurements show diluted magnetic properties for the formed metallic iron, whereas ... more ... Magnetic measurements show diluted magnetic properties for the formed metallic iron, whereas coercivity values were in the range 14.1–55 Oe and saturation magnetization varied from 24.79 to 36.15 emu/g. These values have been ascribed to the formation and growth of ...

Research paper thumbnail of Synthesis of Si 2 N 2 O-SiC composites from desert sand

Transactions of the JWRI, 2002

Trans. JWRI, Vol.31, (2002), No.l 1UU £ 80 - Si2N20 *_^^ ^**"*#^^ a s. о 60 - ^\^ . и **>... more Trans. JWRI, Vol.31, (2002), No.l 1UU £ 80 - Si2N20 *_^^ ^**"*#^^ a s. о 60 - ^\^ . и **>^ ^0/í****' & j><\^ 40 - ^*^^ ^^* Л ^t//>^^ Ы) à^^^ 20 - SiC^-"^^ 0 - ' 1 ' 1 ' 1 ' 1 ' 0.2 0.4 0.6 Y (mole) 0.8 Fig. 3 Change of composition in the synthesized Si2N20-SiC composites. . 99 - ...

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