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# arev:/usr/local/unicat/unireq/beamreq/req00048.txt
# UNICAT Member Beam Time Request  #48

# created Mon Mar 01 13:50:17 CST 1999
#

days:
	5

description:
	(1) Under low-stress high-temperature deformation, silicon nitride
	ceramics often fail by creep rupture. To design creep-rupture resistant
	ceramics, it is necessary to understand the microstructural origins of 
	the creep damage that limit the lifetime under load. USAXS will be used
	to obtain the size distribution of creep cavities in several represent-
	ative specimens.
	
	(2) Fly ash and silica fume suspensions: We would like to see how the
	addition of polymer dispersants affects the agglomertion effects in 
	these systems. This would amount to 5-6 samples mounted within the 
	liquid cells. Compositions would be SiO2, and CaO.SiO2.MgO complexes 
	within H2O. There are no safety issues.
	
	(3) Freshly made yttria stabilized n-ZrO2 suspensions in dilute acidic,
	alkaline and isoelectric suspensions (with Merrillea Mayo). The biggest
	difference between the samples occurs when the samples are fresh. So it
	would be good to measure the fresh samples, then look again about 24 
	hours later. Again these sample would be run in the liquid cells. 
	
	(4) MgAl2O4 studies: (with Gary Gilde and Sam Trevino) Previous meas-
	urements strongly suggest the the transparency and mechanical prop-
	erties are independent of the amount of fine volume-fractal structure 
	within this material but may be degraded in a way that correlates
	with the amount of surface-fractal structure present. This makes sense 
	if the surface fractal microstructure is lying on the surface of larger
	voids. New samples for both SANS and USAXS will be used to investigate
	this issue. These would be 3 - 4 MgAl2O4 samples run in air mounted on
	the sample stage. There would be no safety issues.
	
	(5) X-ray optics: Verify/test monochromator, mirror, M-stage, and 
	A-stage characteristics. -- Naturally, we will do this first, using
	our usual cast of standard non-reactive ceramic samples.

equipment+required:
	no additional equipment

experiment:
	creep in SiN, ceramic suspensions, x-ray optics

hazards:
	The acidic samples (3) fall just within the "hazardous" range. We will
	transport the samples in the safe boxes as advised by Hawoong and be 
	careful not to pour acid down the sink. Apart from using gloves and 
	safety glasses, those are the only issues.
	
	There are no safety issues wuth the samples for (1), (2), (4) and (5).

name:
	Gabrielle Long, A.J. Allen, P. Jemian, J. Ilavsky

nonmembers:
	none

station:
	33ID-D

unacceptable+dates:
	Prefer to have time in the April 22 - May 2 slot.  Other times are
	very difficult due to travel by other members, or international
	visitors.



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