Jump to ContentJump to Main Navigation
Show Summary Details
More options …

American Mineralogist

Journal of Earth and Planetary Materials

Ed. by Baker, Don / Xu, Hongwu / Swainson, Ian


IMPACT FACTOR 2017: 2.645

CiteScore 2017: 2.31

SCImago Journal Rank (SJR) 2017: 1.440
Source Normalized Impact per Paper (SNIP) 2017: 1.059

Online
ISSN
1945-3027
See all formats and pricing
More options …
Volume 100, Issue 8-9

Issues

Melting curve of NaCl to 20 GPa from electrical measurements of capacitive current

Zeyu Li
  • Corresponding author
  • Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109, U.S.A.
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Jie Li
  • Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109, U.S.A.
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2015-08-12 | DOI: https://doi.org/10.2138/am-2015-5248

Abstract

Using an in situ electrical method and the multi-anvil apparatus, we determined the melting curve of sodium chloride (NaC1) up to ~20 GPa, with an estimated uncertainty of ±40 K. Our results agree well with the existing data up to 6.5 GPa. At higher pressures, the melting temperatures from this study are as much as 200 K higher than those from an experimental study using the diamond-anvil cell (DAC), and are up to 500 K lower than those from theoretical studies using molecular dynamics (MD). The discrepancies may originate from surface melting in the DAC measurements, which underestimate the melting temperature, and from superheating in MD calculations, which over-predict the melting temperature. Fitting our results to the Simon equation yield (T/T0)4.5 = (P - P0)/0.6 + 1, where T and T0 are the melting temperatures at P and P0, respectively, with T0 = 1073.6 K, T in K and P in GPa. The Simon equation fits the experimental data within uncertainties and therefore can be used to interpolate the melting curve. Using the equation of state (EoS) of NaCl at 300 K, the results are fitted to the Kraut-Kennedy equation in the form of T/T0 = (V0 - V)/V0·4.37 + 1, where T (in K) and T0 (= 1073.6 K) are the melting temperatures at V and V0 (at 0.0001 GPa), respectively. At pressures above 14 GPa, the experimental data deviate from the Kraut-Kennedy equation fit toward lower temperatures, probably because the volume dependence of the Grüneisen parameter was ignored in the equation. The Gilvarry-Lindemann equation Tm ~ 1.689·f2·Θ02·(V0/V)2(γ-1/3) provides a satisfactory fit to the melting curve of NaCl between 0 and 19 GPa if the exponent q in the volume dependence of the Grüneisen parameter γ = γ0·(V/V0)q is allowed to deviate from one. Given that the melting curve of NaCl up to 6.5 GPa is well established, monitoring the melting of NaCl offers an efficient alternative for pressure calibration of large-volume high-pressure apparatus for Earth science applications.

Keywords: Melting curve; high pressure; capacitive current; in situ electrical method; sodium chloride; Simon equation; Kraut-Kennedy equation; Lindemann’s law

About the article

Received: 2014-11-09

Accepted: 2015-02-23

Published Online: 2015-08-12

Published in Print: 2015-08-01


Citation Information: American Mineralogist, Volume 100, Issue 8-9, Pages 1892–1898, ISSN (Online) 1945-3027, ISSN (Print) 0003-004X, DOI: https://doi.org/10.2138/am-2015-5248.

Export Citation

© 2015 by Walter de Gruyter Berlin/Boston.

Comments (0)

Please log in or register to comment.
Log in