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# Waltraud M. Kriven <kriven@uiuc.edu>
# requesting 6 days, at minimum=6 days
# beamline 33BM, Phase Transformations in Ultra-high Temperature Ceramics
# instrument 33BM-C fourc
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# top:/home/www/beamtime-requests/req00523.txt
# UNICAT Member Beam Time Request  #523
# created Sun Dec 07 15:49:05 CST 2003
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beamline:
	33BM

collaboration:
	Yes

contact:
	kriven@uiuc.edu

days:
	6

description:
	The design of ultra high temperature ceramics requires good knowledge of the crystallographic phase content, phase transformation temperatures, lattice parameters and thermal expansion coefficients at elevated temperatures.  Due to the higher melting point compared to the widely studied ZrO2 based materials (YSZ –yttria stabilized zirconia, ceramics based on HfO2 (doped with Y2O3, TiO2 or Ta2O5) are potentially capable of extending the operating temperature range to >1700 °C. Although a few studies have been conducted in the HfO2-Y2O3 system, little or nothing is known about the HfO2-Ta2O5 or any of the ternary systems. I addition to their refractory nature the ternary materials also show interesting ferroelastic and dielectric properties. We propose to systematically study phase transformations up to 2000 °C in situ, in air, using our quadrupole furnace in ceramic systems based on hafnia and rare earth aluminates, titanates, niobates, and tantalates. Of special interest is the continuation of the work started on the Dy2O3-TiO2 system and the Dy2O3-Al2O3 system, where lattice parameters, unit cell volumes and volume and/or shape changes at phase transformations will be measured.

equipment_required:
	

experiment:
	Phase Transformations in Ultra-high Temperature Ceramics

foreign_nationals:
	Waltraud M. Kriven (Australian)
Kerstin Jurkschat (German)
Pankaj Sarin (Indian)

hazards:
	The in situ experiment uses a four lamp quadrupole furnace to heat up a ceramic sample in air up to ~1800 deg. C.  The instrument is a small, 6 inch diameter apparatus which is water cooled, using a water chiller unit.  No hazards have been experienced with this apparatus to date.

instrument:
	33BM-C fourc

instrument_other:
	

minimumdays:
	6

name:
	Waltraud M. Kriven

nonmembers:
	

unacceptable_dates:
	Not before Feb 29th, 2004
April 18th -21st, 2004

z34ID_details:
	


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