Etude par analyse thermique différentielle des tranformations de phases sur l'iodate de lithium

Patrick Orlans (1, 2) , Etienne Coquet (3) , Jean-Michel Crettez (3) , Bernard Guilhot (1, 2)

1 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
2 P2MC-ENSMSE - Département Poudres et Matériaux Multi-Composants
3 LPUB - Laboratoire de Physique de l'Université de Bourgogne

Lithium iodate (LiIO3) exists at room temperature either as hexagonal (alpha) or tetragonal (beta) crystals. Beta-LiIO3 is stable up to the melting point, whereas alpha-LiIO3 is known to undergo phase transitions. We have studied by differential thermal analysis (DTA) the sequence of phase transitions occurring on powders prepared by different processes. An alpha-LiIO3 powder obtained by grinding a single crystal exhibits the well-known transformations alpha-gamma-beta. A powder obtained by fast evaporation of an aqueous solution transforms directly the alpha to the beta and does not exhibit any intermediate gamma phase. Further, DTA investigations point out that the mechanical treatment, occurred to the sample, plays an important part on these transformations.

Mots clés: ATD; Analyse Thermique Différentielle; iodate de lithium; LiIO3; phase hexagonale; phase tétragonale; transformations de phase

Domaines: Génie des procédés

Patrick Orlans, Etienne Coquet, Jean-Michel Crettez, Bernard Guilhot. Etude par analyse thermique différentielle des tranformations de phases sur l'iodate de lithium. Journées de Calorimétrie d'Analyse Thermique et de Thermodynamique Chimique, Oct 1986, Ferrare, Italie. pp.235-241. ⟨hal-00785290⟩