TY - JOUR
T1 - High temperature plastic flow and grain boundary chemistry in oxide ceramics
AU - Yoshida, H.
AU - Kuwabara, A.
AU - Yamamoto, T.
AU - Ikuhara, Y.
AU - Sakuma, T.
N1 - Funding Information:
The authors wish to express their gratitude to the Ministry of Education, Culture, Sports, Science and Technology and Japan Society for the Promotion of Science for the financial support by a Grant-in-Aid for Scientific Research on Priority Area and Grant-in-Aid for Encouragement of Young Scientists.
PY - 2005/6
Y1 - 2005/6
N2 - High temperature plastic flow or grain boundary failure in oxide ceramics such as Al2O3 and tetragonal ZrO2 polycrystal (TZP) is sensitive to small levels of doping by various cations. For example, high temperature creep deformation in fine-grained, polycrystalline Al 2O3 is highly suppressed by 0.1 mol% lanthanoid oxide or ZrO2-doping. An elongation to failure in superplastic TZP is improved by 0.2-3 mol% GeO2-doping. A high-resolution transmission electron microscopy (HRTEM) observation and an energy-dispersive X-ray spectroscopy (EDS) analysis revealed that the dopant cations tend to segregate along the grain boundaries in Al2O3 and TZP. The dopant effect is attributed to change in the grain boundary diffusivity due to the grain boundary segregation of the dopant cations. A molecular orbital calculation suggests that ionicity is one of the most important parameters to determine the high temperature flow stress, and probably, the grain boundary diffusivity in the oxide ceramics.
AB - High temperature plastic flow or grain boundary failure in oxide ceramics such as Al2O3 and tetragonal ZrO2 polycrystal (TZP) is sensitive to small levels of doping by various cations. For example, high temperature creep deformation in fine-grained, polycrystalline Al 2O3 is highly suppressed by 0.1 mol% lanthanoid oxide or ZrO2-doping. An elongation to failure in superplastic TZP is improved by 0.2-3 mol% GeO2-doping. A high-resolution transmission electron microscopy (HRTEM) observation and an energy-dispersive X-ray spectroscopy (EDS) analysis revealed that the dopant cations tend to segregate along the grain boundaries in Al2O3 and TZP. The dopant effect is attributed to change in the grain boundary diffusivity due to the grain boundary segregation of the dopant cations. A molecular orbital calculation suggests that ionicity is one of the most important parameters to determine the high temperature flow stress, and probably, the grain boundary diffusivity in the oxide ceramics.
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U2 - 10.1007/s10853-005-2674-4
DO - 10.1007/s10853-005-2674-4
M3 - Article
AN - SCOPUS:20544452087
VL - 40
SP - 3129
EP - 3135
JO - Journal of Materials Science
JF - Journal of Materials Science
SN - 0022-2461
IS - 12
ER -