1. First La2O2S infrared transparent ceramics
- Author
-
Alexandre Le Coz, Guillaume R. Durand, Louis Cornet, Nathalie Herbert, Francis Gouttefangeas, Loïc Joanny, Fabrice Célarié, François Cheviré, Odile Merdrignac-Conanec, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Université de Rennes (UR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and French Direction Générale de l’Armement (DGA) and the Ministère des armées - Agence de l’Innovation de Défence (AID)
- Subjects
Hot-pressing ,Materials Chemistry ,Ceramics and Composites ,Young modulus ,[CHIM]Chemical Sciences ,La2O2S ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Vickers hardness ,Infrared transmission - Abstract
International audience; Lanthanum oxysulfide (La2O2S) was investigated as infrared transparent ceramic to benefit from stronger chemical bonds and superior mechanical performances to that of non-oxide benchmark infrared materials. La2O2S ceramics were processed by hot-pressing powders prepared by combustion synthesis followed by a sulfurization treatment. Powders and ceramics were characterised through various techniques (XRD, UV-Vis-IR spectroscopy, particle size analysis, SEM, Impulse Excitation Technique, microhardness and fracture toughness tests) to assess their purity, study their microstructure and determine their optical and mechanical properties. The study reports the first IR transmission spectra, Poisson’s ratio, Young’s and shear moduli and fracture toughness values of La2O2S polycrystalline ceramics. The ceramics showed transparency in the 2-11 μm range and their mechanical performances were all superior to that of commercial infrared ceramics. The best transmission (89% of the theoretical transmission) was measured at 7.3 µm for 1 mm-thick ceramics hot-pressed at 1200-1250°C.
- Published
- 2023