The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
N E Elbaly - One of the best experts on this subject based on the ideXlab platform.
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fabrication of al2o3 20 vol al nanocomposite Powders using high energy Milling and their sinterability
Materials Research Bulletin, 2012Co-Authors: M F Zawrah, H Abdelkader, N E ElbalyAbstract:Highlights: Black-Right-Pointing-Pointer Al{sub 2}O{sub 3}/Al nanocomposite Powders were prepared via high energy ball Milling. After 20 h Milling, the size of Al{sub 2}O{sub 3}-20 vol.% Al nanocomposite particles was in the range of 23-29 nm. A uniform distribution of nanosized Al reinforcement throughout the Al{sub 2}O{sub 3} matrix, coating the particles was successfully obtained. Black-Right-Pointing-Pointer There was no any sign of phase changes during the Milling. A competition between the cold welding mechanism and the fracturing mechanism were found during Milling and finally the above two mechanisms reached an equilibrium. Black-Right-Pointing-Pointer The highest value of relative density was obtained for the sintered bodies at 1500 Degree-Sign C. Black-Right-Pointing-Pointer The harness of the sintered composite was decreased while the fracture toughness was improved after addition Al into alumina. -- Abstract: In this study, alumina-based matrix nanocomposite Powders reinforced with Al particles were fabricated and investigated. The sinterability of the prepared nanocomposite Powder at different firing temperature was also conducted. Their mechanical properties in terms of hardness and toughness were tested. Alumina and aluminum Powder mixtures were milled in a planetary ball mill for various times up to 30 h in order to produce Al{sub 2}O{sub 3}-20% Al nanocomposite. The phase composition,more » morphological and microstructural changes during mechanical Milling of the nanocomposite particles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) techniques, respectively. The crystallite size and internal strain were evaluated by XRD patterns using Scherrer methods. A uniform distribution of the Al reinforcement in the Al{sub 2}O{sub 3} matrix was successfully obtained after Milling the Powders. The results revealed that there was no any sign of phase changes during the Milling. The crystal size decreased with the prolongation of Milling times, while the internal strain increased. A simple model is presented to illustrate the mechanical alloying of a ductile-brittle component system. A competition between the cold welding mechanism and the fracturing mechanism were found during Powder Milling and finally the above two mechanisms reached an equilibrium. The maximum relative density was obtained at 1500 Degree-Sign C. The harness of the sintered composite was decreased while the fracture toughness was improved after addition Al into alumina.« less
Neil M. White - One of the best experts on this subject based on the ideXlab platform.
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Improving the piezoelectric properties of thick-film PZT: the influence of paste composition, Powder Milling process and electrode material
Sensors and Actuators A-physical, 2004Co-Authors: Russel Torah, Stephen Beeby, Neil M. WhiteAbstract:This paper details improvements of the d33 coefficient for thick-film Lead–Zirconate–Titanate (PZT) layers. In particular, the effect that the Powder Milling process has on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled Powders were obtained from Morgan Electro-Ceramics Ltd. These Powders were mixed with various ratios of lead borosilicate glass in the range of 5–20% by weight and an appropriate quantity of Electro-Science Laboratories (ESL) 400 solvent to formulate a screen printable thixotropic paste. The use of a polymer top electrode to reduce the number of firing cycles the PZT layer is subjected to was also investigated. The results show that the highest values of d33 were obtained from the ball milled Powder with 10% glass content, but the most consistent results were obtained from the attritor milled samples. The samples printed with a polymer top electrode have shown an average increase of around 15% in the value of d33.
Guojun Zhang - One of the best experts on this subject based on the ideXlab platform.
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spark plasma sintering of b4c ceramics the effects of Milling medium and tib2 addition
International Journal of Refractory Metals & Hard Materials, 2012Co-Authors: Changming Xu, Katarina Flodstrom, Zheshen Li, Saeid Esmaeilzadeh, Guojun ZhangAbstract:Abstract Boron carbide (B 4 C) ceramics, with a relative density up to 98.4% and limited grain growth, were prepared at 1600–1800 °C by spark plasma sintering (SPS) technique. The effects of Powder Milling medium (water and 2-propanol) on the Powders' surface characteristics and TiB 2 addition on the sintering densification were investigated. The ball Milling processing of B 4 C Powders in water can promote the sintering of B 4 C ceramics. A B 2 O 3 layer on B 4 C particle surface is concluded to promote the densification of the B 4 C ceramics at an early sintering stage. This B 2 O 3 layer, which normally inhibits the densification process at the final stage of the sintering, can be reduced through reaction with TiB 2 particles, resulting in further densification of the B 4 C ceramics.
M F Zawrah - One of the best experts on this subject based on the ideXlab platform.
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fabrication of al2o3 20 vol al nanocomposite Powders using high energy Milling and their sinterability
Materials Research Bulletin, 2012Co-Authors: M F Zawrah, H Abdelkader, N E ElbalyAbstract:Highlights: Black-Right-Pointing-Pointer Al{sub 2}O{sub 3}/Al nanocomposite Powders were prepared via high energy ball Milling. After 20 h Milling, the size of Al{sub 2}O{sub 3}-20 vol.% Al nanocomposite particles was in the range of 23-29 nm. A uniform distribution of nanosized Al reinforcement throughout the Al{sub 2}O{sub 3} matrix, coating the particles was successfully obtained. Black-Right-Pointing-Pointer There was no any sign of phase changes during the Milling. A competition between the cold welding mechanism and the fracturing mechanism were found during Milling and finally the above two mechanisms reached an equilibrium. Black-Right-Pointing-Pointer The highest value of relative density was obtained for the sintered bodies at 1500 Degree-Sign C. Black-Right-Pointing-Pointer The harness of the sintered composite was decreased while the fracture toughness was improved after addition Al into alumina. -- Abstract: In this study, alumina-based matrix nanocomposite Powders reinforced with Al particles were fabricated and investigated. The sinterability of the prepared nanocomposite Powder at different firing temperature was also conducted. Their mechanical properties in terms of hardness and toughness were tested. Alumina and aluminum Powder mixtures were milled in a planetary ball mill for various times up to 30 h in order to produce Al{sub 2}O{sub 3}-20% Al nanocomposite. The phase composition,more » morphological and microstructural changes during mechanical Milling of the nanocomposite particles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) techniques, respectively. The crystallite size and internal strain were evaluated by XRD patterns using Scherrer methods. A uniform distribution of the Al reinforcement in the Al{sub 2}O{sub 3} matrix was successfully obtained after Milling the Powders. The results revealed that there was no any sign of phase changes during the Milling. The crystal size decreased with the prolongation of Milling times, while the internal strain increased. A simple model is presented to illustrate the mechanical alloying of a ductile-brittle component system. A competition between the cold welding mechanism and the fracturing mechanism were found during Powder Milling and finally the above two mechanisms reached an equilibrium. The maximum relative density was obtained at 1500 Degree-Sign C. The harness of the sintered composite was decreased while the fracture toughness was improved after addition Al into alumina.« less
Russel Torah - One of the best experts on this subject based on the ideXlab platform.
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Improving the piezoelectric properties of thick-film PZT: the influence of paste composition, Powder Milling process and electrode material
Sensors and Actuators A-physical, 2004Co-Authors: Russel Torah, Stephen Beeby, Neil M. WhiteAbstract:This paper details improvements of the d33 coefficient for thick-film Lead–Zirconate–Titanate (PZT) layers. In particular, the effect that the Powder Milling process has on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled Powders were obtained from Morgan Electro-Ceramics Ltd. These Powders were mixed with various ratios of lead borosilicate glass in the range of 5–20% by weight and an appropriate quantity of Electro-Science Laboratories (ESL) 400 solvent to formulate a screen printable thixotropic paste. The use of a polymer top electrode to reduce the number of firing cycles the PZT layer is subjected to was also investigated. The results show that the highest values of d33 were obtained from the ball milled Powder with 10% glass content, but the most consistent results were obtained from the attritor milled samples. The samples printed with a polymer top electrode have shown an average increase of around 15% in the value of d33.