A laser study of the CeO2 solid/liquid equilibrium: challenges related to a refractory compound with a very high oxygen pressure

A laser heating technique is employed to study the melting behaviour of cerium dioxide, CeO2, a refractory compound with very high oxygen pressure. The strong tendency of cerium dioxide to reduce to hypostoichiometric compounds, even in the presence of oxygen traces, lead to discrepancies in the measured melting temperature depending on whether an oxidising or a reducing atmosphere is used during the experiment. The purpose of this study is to measure the melting temperature of initially stoichiometric CeO2 under different controlled atmospheres, reducing or oxidizing. A high pressure cell was used to limit the oxygen loss and attempt a measure of the melting temperature of the stoichiometric compound. The results confirm a strong influence of the atmosphere on the melting temperature. The measured values are in line with existing literature data obtained under different conditions. Only under a high buffer gas pressure (He at 15 MPa) the highest reported temperature of 3000 K could be observed here, although with poor repeatability.

CAPRIOTTI Luca;  QUAINI Andrea;  BÖHLER Robert;  BOBORIDIS Konstantinos;  LUZZI Lelio;  MANARA Dario; 

2015-12-11

OLD CITY PUBLISHING INC

JRC91180

0018-1544,   

http://www.oldcitypublishing.com/journals/hthp-home/hthp-issue-contents/hthp-volume-44-number-1-2015/,    http://www.oldcitypublishing.com/wp-content/uploads/2015/01/HTHPv44n1p69-82Capriotti.pdf,    https://publications.jrc.ec.europa.eu/repository/handle/JRC91180,