The stability and the thermo-elastic behaviour of a natural londonite has been investigated up to 1,273(3) K (at 0.0001 GPa) and up to 4.85(5) GPa (at 298 K) by means of in situ X-ray powder diffraction. Up to 973 K, no evidence of phase transition or anomalous thermo-elastic behaviour was observed. At T > 973 K, londonite shows the first evidence of an irreversible structure destabilisation. The volume thermal expansion coefficient between 298 and 973 K is α0 = 2.38(6)·10-5 K-1. Londonite shows an elastic behaviour up to 4.85 GPa. No phase transition has been observed within the pressure range investigated. P-V data fitted with a second-order Birch-Murnaghan equation of state give V0 = 389.1(1)Å3 and KT0 = 280(12) GPa. On the basis of the good thermo-elastic behaviour, substantiated by the significantly low compressibility, the modest thermal expansion up to 1,000 K and the significantly high amount of boron (B2O3 ~ 50wt%), londonite-type materials could be considered as potential inorganic host for 10B in composite neutron-absorbing materials.
Bibliographical noteFunding Information:
The authors are grateful to N. Marinoni and E. Ferrari (Milan). The research was financially supported by University of Milan (PUR2009) and CNR-IDPA. Y. Lee thanks the support by the National Research Foundation through the Nuclear R&D Program (Grant No. M2AM06-2008-03931). Experiments at PAL were supported by Ministry of Education, Science and Technology of the Korean Government and POSTECH. Two anonymous reviewers and the Editor M. Rieder are thanked for their suggestions.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Geochemistry and Petrology