Photon Factory Activity Report 2005 #23 Part B (2006)
Crystallography

4B2/2004G058,2004G256, 2005G157, 2005G158

A new electric furnace for synchrotron powder diffraction
measurements up to 1807 K

Masatomo YASHIMA1,*, Masahiko TANAKA2, Kenjiro OH-UCHI,1 Takashi IDA3
Department of Materials Science and Engineering, Interdisciplinary Graduate School of Scienceand Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama,Kanagawa, 226-8502, Japan;
2
WEBRAM, National Institute for Materials Science, SPring-8, 1-1-1 Kouto Mikazuki-cho
Sayo-gun Hyogo 679-5198, Japan
3
Ceramics Research Laboratory, Nagoya Institute of Technology, Asahigaoka 10-6-29, Tajimi, Gifu
507-0071, Japan
1Introduction
High-temperature synchrotron powder diffractometry
is a powerful method to study the crystal structure andphase transformation at high temperatures. Here we
report a new compact electric furnace to measure thehigh-resolution synchrotron powder diffraction profiles
from materials at high temperatures up to 1807 K in air,using the multiple-detector system at the BL-4B2 station(Yashima et al., J. Appl. Crystallogr., 38 (2005) 854-855,J. Am. Ceram. Soc., 89 (2006) 1395-1399).

Design of the new furnace
We have designed and fabricated a new electric
furnace to measure high-resolution synchrotron powder
diffraction data from the specimen at high temperatures
up to 1807 K in air. This furnace consists of ceramic
refractory with MoSi2 heaters, steel body cooled byflowing water and an automatic sample stage. The sample
stage can be rotated about the normal to the sample
surface and the position of the sample along the normal
direction can be adjusted with a stepping motor. The
specimen can quickly be exchanged without the need forfurther alignment of the furnace. Except for the beryllium
or aluminum window for the thermal shield, no part of thefurnace exists in the paths of the incident X-ray anddiffraction signals from the sample to the Soller slits,
leading to high-quality synchrotron powder diffraction
data as described below. The temperature of the furnace
was controlled with an R-type (Pt/Pt-13wt%Rh)
thermocouple placed between the sample and heater. A
heating test was performed from room temperature to1807 K using the new furnace attached to themultiple-detector system installed at the BL-4B2
experimental station of the Photon Factory, High Energy
Accelerator Research Organization (KEK), Japan. The
present furnace exhibited good temperature stability: thechange of temperature with time was small. For example,
the temperature at the thermocouple for control was able
to be kept constant at 1773.1±0.1 K. Diffraction datafrom the NIST ceria powder at 1703 K in air werecollected in asymmetric flat-specimen reflection
geometry.

Performance of the new furnace
The whole powder pattern of NIST SRM ceria wasscanned at a step interval of 0.004 deg. in 2θ andcounting time of 1.5 s step-1, in just 7 hours. It should be
noted that no extra peaks appeared in the whole
diffraction pattern. The background intensity wasextremely low (8-30 counts) comparing with the strongest
peak intensity (56047 counts) in the data measured at1703 K. It means that the present furnace shows
significant performance for precise evaluation ofdiffraction peak intensities considerably reduced bytemperature factors at high 2θ angles, and it is also
expected to be useful for study on diffuse scattering athigh temperatures. It has been also confirmed thathigh-resolution diffraction data are obtained with thecurrent system even at high temperatures. The full widthat half maximum of the ceria at 1703 K was in the range
from 0.0139 deg. at 2θ=21.83 deg. to 0.0575 deg. at
2θ=114.23 deg. Corresponding δd/d resolution wasranged from 0.058 to 0.126 % at 1703 K where d and δd
are the lattice spacing and peak width, respectively. These
results indicate that the present new furnace yields
high-quality, high-temperature and high-resolution
synchrotron
powderdiffraction
data.
This
high-temperature system would yield many applications
in high-temperature crystallography and structuralscience.

FurnaceFig.1. Photograph of the new furnace placed on thestage of the diffractometer at the beam line 4B2of the Photon Factory.
* yashima@materia.titech.ac.jp

Users' Report

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