Beschreibung:
<jats:p>The lattice parameters of synthetic diaspore (AlO(OH)) and synthetic and natural corundum (Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>) have been measured at simultaneously elevated pressure and temperature up to 7 GPa and 800°C (1000°C for corundum) using a MAX 80 cubic anvil high‐pressure apparatus. Several experimental runs were carried out for both minerals, in which the samples were first compressed at room temperature and then heated; NaCl served as an internal standard for pressure calibration. In most runs the samples were mixed with Vaseline or NaCl to ensure hydrostatic pressure‐transmitting conditions. Some runs, mainly at pressures <4 GPa, were performed without using a pressure medium. A Birch‐Murnaghan equation of state (EOS) was fitted to the experimental data obtained at room temperature (assuming <jats:italic>K</jats:italic><jats:sup>′</jats:sup> = 4), yielding bulk moduli K (diaspore) = 134.4±1.4 GPa in contrast to 230 GPa obtained from diamond anvil cell measurements without using a pressure medium recently, and <jats:italic>K</jats:italic> (corundum) = 219.1±3.5 GPa, consistent with previous results based on X‐ray diffraction measurements in conjunction with multi‐anvil high‐pressure techniques. The high‐temperature Birch‐Murnaghan EOS was fitted to the high‐temperature high‐pressure diaspore data, <jats:italic>P</jats:italic> = 1.5<jats:italic>K</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub>[<jats:italic>V</jats:italic><jats:sub><jats:italic>T,r</jats:italic></jats:sub><jats:sup>−7</jats:sup> ‐ <jats:italic>V</jats:italic><jats:sub><jats:italic>T,r</jats:italic></jats:sub><jats:sup>−5</jats:sup>][1 ‐ 0.75 (4 ‐ <jats:italic>K</jats:italic>′<jats:sub><jats:italic>T</jats:italic></jats:sub>) <jats:italic>V</jats:italic><jats:sub><jats:italic>T,r</jats:italic></jats:sub><jats:sup>−2</jats:sup> ‐ 1], <jats:italic>V</jats:italic><jats:sub><jats:italic>T,r</jats:italic></jats:sub> ≡ (<jats:italic>V</jats:italic>/<jats:italic>V</jats:italic><jats:sub><jats:italic>T</jats:italic>,0</jats:sub>)<jats:sup>1/3</jats:sup>, <jats:italic>K</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub> = <jats:italic>K</jats:italic> + (∂<jats:italic>K</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub>/∂<jats:italic>T</jats:italic>)<jats:sub><jats:italic>P</jats:italic></jats:sub>(<jats:italic>T</jats:italic> ‐ 298.15), <jats:italic>V</jats:italic><jats:sub><jats:italic>T</jats:italic>,0</jats:sub> = 117.84 Å<jats:sup>3</jats:sup> exp (∫a+b<jats:italic>T</jats:italic>d<jats:italic>T</jats:italic>), resulting in <jats:italic>K</jats:italic> = 133.6±4.0 Gpa,<jats:italic>K</jats:italic>′<jats:sub><jats:italic>T</jats:italic></jats:sub> = 4.1±1.5, (∂<jats:italic>K</jats:italic><jats:sub><jats:italic>T</jats:italic></jats:sub>/∂<jats:italic>T</jats:italic>)<jats:sub><jats:italic>P</jats:italic></jats:sub> = −0.017±0.007 Gpa K<jats:sup>−1</jats:sup>, a = 2.22±0.40 10<jats:sup>−5</jats:sup> K<jats:sup>−1</jats:sup>, and b = 2.23±0.79 10<jats:sup>−8</jats:sup> K<jats:sup>−2</jats:sup>.</jats:p>