Cobalt-doped magnesium oxide pressure-transmitting medium for high pressure and high-temperature apparatus

ABSTRACT

Magnesium oxide (MgO) doped with cobalt (Co) semi-sintered pressure-transmitting medium (MCOPM) was prepared at 1200°C in air, starting with a pre-compressed mixture of MgO and cobalt oxide (CoO). The samples were characterized using powder X-ray diffraction, scanning electron microscopy, and thermal conductivity measurements. The results demonstrate that during the sintering process, the exchange of metal ions between the mixture powders introduced lattice defects into the MgO lattice structure, and an MgO–CoO solid solution was formed. Compared to commercial semi-sintered MgO pressure-transmitting medium (SSMPM), the temperature-generation efficiency of MCOPM-17 (MgO + 17 mol% CoO) improved by about 220% at the high pressure of 12 GPa with a cell assembly in a two-stage multi-anvil large volume press. Moreover, the thermal conductivity of CoO-doped MgO decreased with increasing CoO doping.

KEYWORDS:

• Pressure medium
• MgO–CoO solid solution
• high pressure and high-temperature
• thermal conductivity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Key Laboratory of Neutron Physics CAEP (2014AB02) and National Natural Science Foundation of China [grant nos 51472171 and 11427810].