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Effects of Sintering Temperature on Open‐Volume Defects and Thermoluminescence of Yttria and Lutetia Ceramics
Author(s) -
Chapman Matthew G.,
Walker Roger C.,
Schmitt Jaclyn M.,
McPherson Cameron L.,
Ameena Fnu,
Kucera Courtney J.,
Quarles Carroll A.,
DeVol Timothy A.,
Ballato John,
Jacobsohn Luiz G.
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14119
Subject(s) - sintering , materials science , ceramic , calcination , thermoluminescence , volume (thermodynamics) , mineralogy , analytical chemistry (journal) , composite material , metallurgy , luminescence , thermodynamics , chemistry , optoelectronics , biochemistry , physics , catalysis , chromatography
The effects of different processing steps and processing conditions for the fabrication of Y 2 O 3 and Lu 2 O 3 ceramics were investigated, particularly the effects of calcination, and sintering temperature on the content of open‐volume and electronic defects. Ceramic bodies were prepared from calcined powders by sintering from 1400°C to 1700°C for 20 h. Density was determined by the Archimedes method and showed pellets reached about 99% of Y 2 O 3 density for temperatures ≥1450°C, and reached 98% for sintering at 1700°C for Lu 2 O 3 . The content of open‐volume defects was followed by positron annihilation lifetime ( PAL ) measurements. For both materials, two lifetimes were obtained. The faster lifetime, 211 ps for Y 2 O 3 and 204 ps for Lu 2 O 3 , was assigned to bulk annihilation with possible contribution of grain boundaries. The longer lifetime was assigned to positronium annihilation in open‐volume defects with radii of 2–4 Å. Doppler broadening analysis revealed the same type of defect in Lu 2 O 3 ceramics for all sintering temperatures. PAL analysis results showed that densification was achieved through the elimination and agglomeration of open‐volume defects. Thermoluminescence ( TL ) measurements of Y 2 O 3 showed that sintering is beneficial in eliminating traps and/or recombination centers, and that higher sintering temperatures increase TL signal.