TY - JOUR
T1 - Improvement of creep resistance in polycrystalline Al2O3 by Lu-doping
AU - Yoshida, H.
AU - Ikuhara, Y.
AU - Sakuma, T.
N1 - Funding Information:
The authors wish to express their gratitude to the Ministry of Education, Science and Culture, Japan, for the financial support by a Grant-in-Aid for Developmental Scientific Research (2)–1045 0254 for Fundamental Scientific Research.
PY - 1999
Y1 - 1999
N2 - High-temperature creep resistance in high-purity Al2O3 (nominal purity of 99.99%) and Al2O3 doped with 0.05 mol% Lu2O3 was examined by uniaxial compression testing in air at a constant load at temperatures between 1150 and 1350°C and the applied stress range of 10~200 MPa. The creep resistance was found to highly improve in this temperature range by doping of Lu2O3 into polycrystalline Al2O3 even at the level of 0.05 mol%. The stress exponent was about 2 in the two materials, but the activation energy for creep was different; 410 kJ/mol for undoped Al2O3 and 780 kJ/mol for Lu2O3-doped Al2O3. Lutetium ions were found to segregate in Al2O3 grain boundaries without forming amorphous phase or second-phase particles. The improved creep resistance in polycrystalline Al2O3 due to Lu2O3 doping was attributed to the segregation of Lu ions in Al2O3 grain boundaries probably due to the suppression of grain boundary diffusion. The change of chemical bonding state in grain boundaries with the segregation of Lu ions is supposed by HREM-EELS analysis.
AB - High-temperature creep resistance in high-purity Al2O3 (nominal purity of 99.99%) and Al2O3 doped with 0.05 mol% Lu2O3 was examined by uniaxial compression testing in air at a constant load at temperatures between 1150 and 1350°C and the applied stress range of 10~200 MPa. The creep resistance was found to highly improve in this temperature range by doping of Lu2O3 into polycrystalline Al2O3 even at the level of 0.05 mol%. The stress exponent was about 2 in the two materials, but the activation energy for creep was different; 410 kJ/mol for undoped Al2O3 and 780 kJ/mol for Lu2O3-doped Al2O3. Lutetium ions were found to segregate in Al2O3 grain boundaries without forming amorphous phase or second-phase particles. The improved creep resistance in polycrystalline Al2O3 due to Lu2O3 doping was attributed to the segregation of Lu ions in Al2O3 grain boundaries probably due to the suppression of grain boundary diffusion. The change of chemical bonding state in grain boundaries with the segregation of Lu ions is supposed by HREM-EELS analysis.
KW - A. ceramics, structural materials
KW - C. electron energy loss spectroscopy (EELS)
KW - D. mechanical properties
UR - http://www.scopus.com/inward/record.url?scp=0039726840&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0039726840&partnerID=8YFLogxK
U2 - 10.1016/s1466-6049(99)00035-5
DO - 10.1016/s1466-6049(99)00035-5
M3 - Article
AN - SCOPUS:0039726840
VL - 1
SP - 229
EP - 234
JO - International Journal of Inorganic Materials
JF - International Journal of Inorganic Materials
SN - 1466-6049
IS - 3-4
ER -