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Diffusionless Phase Transformations in Zirconia and Hafnia
Author(s) -
WOLTEN G. M.
Publication year - 1963
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/j.1151-2916.1963.tb11768.x
Subject(s) - hafnia , monoclinic crystal system , tetragonal crystal system , cubic zirconia , materials science , hysteresis , phase (matter) , crystallography , martensite , diffusionless transformation , crystal structure , condensed matter physics , chemistry , metallurgy , microstructure , ceramic , physics , organic chemistry
A study, by high‐temperature diffractometry, of the monoclinic‐tetragonal phase changes in pure ZrO 2 and HfO 2 disclosed that the hysteresis loops associated with the transformations have similar shapes which are typical of many martensitic phase changes, but that the widths of the loops differ greatly for the two materials, being about 200°C for zirconia and only 20° to 30°C for hafnia. The temperature‐induced transformations are predominantly athermal. The nature of these and similar transformations is discussed. The reversible formation of a cubic form of ZrO 2 above 2200°C was confirmed.