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Thermal expansion and the high–low transformation in quartz. I. High‐temperature X‐ray studies
Author(s) -
Ackermann R. J.,
Sorrell C. A.
Publication year - 1974
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889874010211
Subject(s) - thermal expansion , quartz , transformation (genetics) , thermodynamics , plane (geometry) , volume (thermodynamics) , materials science , hysteresis , x ray , volume expansion , analytical chemistry (journal) , mineralogy , chemistry , condensed matter physics , physics , geometry , optics , composite material , mathematics , medicine , biochemistry , chromatography , gene
The (100) and (101) interplanar spacings of 400 mesh quartz powder were measured by high‐temperature X‐ray diffractometry from 22 to 1400°C. Expansion through the high‐low transformation was reversible and continuous, with evidence of 1–2° hysteresis; expansion from 574 to 1000° is zero, with a net decrease from 1000 to 1400°. Maximum linear coefficients of expansion at the transformation were 400±50 x 10 −6 deg −1 across the (100) plane and 140±30 x 10 −6 deg −1 across the (101) plane. The maximum volume coefficient of expansion was 100±20 × 10 −5 deg −1 between 572 and 574°. Differential thermal analyses provided ambiguous data, indicating a latent heat of transformation of 160±40 cal/mole, in apparent contradiction with thermal expansion measurements.