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Abstract The thermal equation of state (TEOS) for solids is a mathematic model among pressure, temperature and density, and is essential for geophysical, geochemical, and other high pressure–temperature (high P–T) researches. However, in the last few decades, there has been a growing concern about the accuracy of the pressure scales of the calibrants, and efforts have been made to improve it by either introducing a reference standard or building new thermal pressure models. The existing thermal equation of state,P(V,T) = P(V,T0) + Pth(V,T), consists of an isothermal compression and an isochoric heating, while the thermal pressure is the pressure change in the isochoric heating. In this paper, we demonstrate that, for solids in a soft pressure medium in a diamond anvil cell, the thermal pressure can neither be determined from a single heating process, nor from the thermal pressure of its calibrant. To avoid the thermal pressure, we propose to replace the thermal pressure with a well-known thermal expansion model, and integrate it with the isothermal compression model to yields a Birch–Murnaghan-expansion TEOS model, called VPT TEOS. The predicted pressure of MgO and Au at ambient pressure from Birch–Murnaghan-expansion VPT TEOS model matches the experimental pressure of zero (0) GPa very well, while the pressure prediction from the approximated Anderson PVT TEOS exhibit a big deviation and a wrong trend.
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Effect of tetraethoxysilane (TEOS) on melting gel behavior
Abstract To increase the connectivity of the molecular structure but not to prevent softening, small amounts of tetraethoxysilane (TEOS) were added to phenyl‐substituted melting gels. The limit of the additions was determined when the melting gel lost its ability to soften. A comparison was made between TEOS diluted with ethanol, TEOS diluted with methanol, and tetramethoxysilane (TMOS) diluted with methanol. The additions had slight effects on the glass transition behavior, the gelling time and the indentation hardness. The role of the TEOS was both a form of dilution and a cross‐linking promoter.
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- Award ID(s):
- 1911509
- PAR ID:
- 10457090
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of the American Ceramic Society
- Volume:
- 103
- Issue:
- 8
- ISSN:
- 0002-7820
- Page Range / eLocation ID:
- p. 4140-4149
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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