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A room-temperature phase transition in maximum microcline - Heat capacity measurements

Physics and Chemistry of Minerals

By:
, , ,
DOI: 10.1007/BF00308170

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Abstract

The thermal hysteresis in heat capacity measurements recently reported (Openshaw et al., 1976) for a maximum microcline prepared from Amelia albite by fused-salt ion-exchange is described in detail. The hysteresis is characterized by two limiting and reproducible curves which differ by 1% of the measured heat capacities. The lower curve, denoted curve B, represents the values obtained before the sample had been cooled below 300 K. Measurements made immediately after cooling the sample below 250 K followed a second parallel curve, curve A, to at least 370 K. Values intermediate to the two limiting curves were also obtained. The transitions from the B to the A curve were rapid and observed to occur three times. The time required to complete the transition from the A to the B curve increased from 39 h to 102 h in the two times it was observed to occur. The hysteresis is interpreted as evidence of a phase change in microcline at 300??10 K The heat effect associated with the phase change has not been evaluated. ?? 1979 Springer-Verlag.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
A room-temperature phase transition in maximum microcline - Heat capacity measurements
Series title:
Physics and Chemistry of Minerals
DOI:
10.1007/BF00308170
Volume
5
Issue:
1
Year Published:
1979
Language:
English
Publisher location:
Springer-Verlag
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Physics and Chemistry of Minerals
First page:
83
Last page:
93
Number of Pages:
11