Densification and Electrical Resistance of Y₂O₃ at Various Pressures

Abstract

The densification of Y₂O₃ has been previously reported by various investigators [1–4]. Schieitz and Wilder [1] studied the sintering of Y₂O₃ from 1210 to 1643°C in a vacuum furnace, with difficulties encountered in its complete densification and interpretation of the sintering data in terms of sintering models based on volume and grain boundary diffusion. Jorgensen and Anderson [2] showed that the addition of up to 10 m% ThO₂ to Y₂O₃ inhibits grain growth during sintering, and allows the sintering process to proceed to essentially theoretical density of the specimens. These investigators [2] were unable to obtain theoretical density of the pure Y₂O₃ specimens heated to 2000°C in a resistance furnace. Transparent Y₂O₃ was reported by Lefever and Matsko [3] using vacuum hot pressing at 950°C and pressures up to 830 bars. Füll transparency was achieved according to these investigators [3] by adding LiF to Y₂O₃. Dutta and Gazza [4] used vacuum hot pressing at temperatures ranging from 1300 to 1500°C and pressures up to 480 bars to produce transparent Y₂O₃ specimens. The present work was undertaken in order to determine the densification of Y₂O₃ with or without ThO₂ additions using vacuum sintering, regulär hot pressing, and high pressure hot pressing techniques.