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Bulk samples of lanthanum polyphosphate were synthesized through a hydrothermal hot-pressing (HHP) process. In this process, pressing temperature, pressure and volume of water were varied in order to improve the density and strength of the resulting materials. The strength of the bulk samples was estimated through drilling and ultrasonic treatments. In order to improve the strength of the materials, the use of microwave irradiation was examined. Lanthanum polyphosphate formed porous bulk samples with a filling factor of approximately 70%, which was calculated from real and theoretical densities. With respect to machinable strength, a drilled hole greater than 7.0 mm in diameter was obtained on some bulk samples, and the diameter of the samples was 14 mm. The HHP process is a useful method for obtaining bulk samples of lanthanum polyphosphate. Bulk lanthanum polyphosphate containing water crumbled easily to a powder form upon ultrasonication. However, these bulk samples retained their shape upon ultrasonication, despite containing water, after exposure to microwave irradiation, and also experienced minimal weight loss. Furthermore, to study the effect of microwave heating, bulk lanthanum orthophosphate, yttrium orthophosphate and polyphosphate were also examined.


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Synthesis of bulk lanthanum polyphosphate and other rare earth phosphates through hydrothermal hot-pressing

Show Author's information Hiroaki ONODA*( )Taro YAMASAKI
Department of Informatics and Environmental Sciences, Faculty of Life and Environmental Sciences, Kyoto Prefectural University, 1-5, Shimogamo Nakaragi-cho, Sakyo-ku, Kyoto 606-8522, Japan

Abstract

Bulk samples of lanthanum polyphosphate were synthesized through a hydrothermal hot-pressing (HHP) process. In this process, pressing temperature, pressure and volume of water were varied in order to improve the density and strength of the resulting materials. The strength of the bulk samples was estimated through drilling and ultrasonic treatments. In order to improve the strength of the materials, the use of microwave irradiation was examined. Lanthanum polyphosphate formed porous bulk samples with a filling factor of approximately 70%, which was calculated from real and theoretical densities. With respect to machinable strength, a drilled hole greater than 7.0 mm in diameter was obtained on some bulk samples, and the diameter of the samples was 14 mm. The HHP process is a useful method for obtaining bulk samples of lanthanum polyphosphate. Bulk lanthanum polyphosphate containing water crumbled easily to a powder form upon ultrasonication. However, these bulk samples retained their shape upon ultrasonication, despite containing water, after exposure to microwave irradiation, and also experienced minimal weight loss. Furthermore, to study the effect of microwave heating, bulk lanthanum orthophosphate, yttrium orthophosphate and polyphosphate were also examined.

Keywords:

lanthanum polyphosphate, hydrothermal hot-pressing (HHP) process, machinable strength, vibration strength, microwave heating
Received: 01 April 2013 Revised: 10 July 2013 Accepted: 11 July 2013 Published: 04 December 2013 Issue date: December 2013
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Publication history

Received: 01 April 2013
Revised: 10 July 2013
Accepted: 11 July 2013
Published: 04 December 2013
Issue date: December 2013

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© The author(s) 2013

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