TY - GEN
T1 - Grain-boundary segregation and phase-separation mechanism in yttria-stabilized tetragonal zirconia polycrystal
AU - Matsui, Koji
AU - Yoshida, Hidehiro
AU - Ikuhara, Yuichi
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2011
Y1 - 2011
N2 - Microstructure development during sintering in 3 mol% Y2O 3-stabilized tetragonal ZrO2 polycrystal (Y-TZP) was systematically investigated in two sintering conditions: (a) 1100-1650°C for 2 h and (b) 1300°C for 0-50 h. In the sintering condition (a), the density and grain size in Y-TZP increased with the increasing sintering temperature. Scanning transmission electron microscopy (STEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS) measurements revealed that the Y3+ ion distribution was nearly homogeneous up to 1300°C, i.e., most of grains were the tetragonal phase, but cubic-phase regions with high Y3+ ion concentration were clearly formed in grain interiors adjacent to the grain boundaries at 1500°C. High-resolution transmission electron microscopy (HRTEM) and nanoprobe EDS measurements revealed that no amorphous or second phase is present along the grain-boundary faces, and Y3+ ions segregated not only along the tetragonal-tetragonal phase boundaries but also along tetragonal-cubic phase boundaries over a width below about 10 nm, respectively. These results indicate that the cubic-phase regions are formed from the grain boundaries and/or the multiple junctions in which Y3+ ions segregated. We termed this process a "grain boundary segregation-induced phase transformation (GBSIPT)" mechanism. In the sintering condition (b), the density was low and the grain-growth rate was much slow. In the specimen sintered at 1300°C for 50 h, the cubic-phase regions were clearly formed in the grain interiors adjacent to the grain boundaries. This behavior shows that the cubic-phase regions were formed without grain growth, which can be explained by the GBSIPT model.
AB - Microstructure development during sintering in 3 mol% Y2O 3-stabilized tetragonal ZrO2 polycrystal (Y-TZP) was systematically investigated in two sintering conditions: (a) 1100-1650°C for 2 h and (b) 1300°C for 0-50 h. In the sintering condition (a), the density and grain size in Y-TZP increased with the increasing sintering temperature. Scanning transmission electron microscopy (STEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS) measurements revealed that the Y3+ ion distribution was nearly homogeneous up to 1300°C, i.e., most of grains were the tetragonal phase, but cubic-phase regions with high Y3+ ion concentration were clearly formed in grain interiors adjacent to the grain boundaries at 1500°C. High-resolution transmission electron microscopy (HRTEM) and nanoprobe EDS measurements revealed that no amorphous or second phase is present along the grain-boundary faces, and Y3+ ions segregated not only along the tetragonal-tetragonal phase boundaries but also along tetragonal-cubic phase boundaries over a width below about 10 nm, respectively. These results indicate that the cubic-phase regions are formed from the grain boundaries and/or the multiple junctions in which Y3+ ions segregated. We termed this process a "grain boundary segregation-induced phase transformation (GBSIPT)" mechanism. In the sintering condition (b), the density was low and the grain-growth rate was much slow. In the specimen sintered at 1300°C for 50 h, the cubic-phase regions were clearly formed in the grain interiors adjacent to the grain boundaries. This behavior shows that the cubic-phase regions were formed without grain growth, which can be explained by the GBSIPT model.
KW - Grain boundary segregation-induced phase transformation
KW - Grain-boundary segregation
KW - Microstructure
KW - Phase separation
KW - Sintering
KW - Y-TZP
UR - http://www.scopus.com/inward/record.url?scp=79960679350&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79960679350&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/KEM.484.82
DO - 10.4028/www.scientific.net/KEM.484.82
M3 - Conference contribution
AN - SCOPUS:79960679350
SN - 9783037851814
T3 - Key Engineering Materials
SP - 82
EP - 88
BT - Advanced Engineering Ceramics and Composites
PB - Trans Tech Publications Ltd
ER -