Infrared laser absorption and melting behaviour of nano-sized cerium dioxide: A laser heating study

The absorption of a 1064.5 nm Nd:YAG laser line and the consequent heating up to melting of nano-crystalline CeO2 has been studied in compressed air. The behaviour of crystallites ranging from 3.2 nm to 11 nm has been investigated and compared with micro-crystalline CeO2. A transparent / opaque transition occurs in CeO2 at lower heating laser power density in smaller crystallite sizes. Also the melting behaviour is strongly dependent on the crystallite size. If one manages to directly melt nano-crystals by optimising the heating conditions under a suited oxygen overpressure, the resulting melt has been observed to solidify at the highest temperature so far reported for CeO2 (3012 K), about 250 K higher than the temperature most commonly registered under oxidising conditions (2750 K). This is attributable to the large specific surface of nano-crystals, resulting, under a high oxygen potential, in their higher stability with respect to oxygen losses.

MANARA Dario;  POPA Karin;  ROBBA Davide;  FONGARO Lorenzo;  COLLE Jean-Yves;  BULGHERONI Antonio; 

2021-05-12

ELSEVIER SCI LTD

JRC120421

0955-2219 (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC120421,   

10.1016/j.jeurceramsoc.2020.09.026 (online),