Solution solide d’apatites de plomb, d’argent et de sodium : synthèse, caractérisation structurale et propriétés électriques

Abstract

Abstract.A continuous solid solution of Pb 8 Na 2-x Ag x (PO 4 ) 6 (0≤ x ≤2) crystallizing in the anionicdeficient apatite structure was obtained by solid-state reaction. The samples were characterized by using X-ray diffraction, infrared absorption spectroscopy, Raman scattering spectroscopy, 31 P MAS-NMR and chemical analysis. The electrical conductivity versus x measured in a wide range of temperature increases with silver content. For each composition, conductivity values obey the Arrhenius law. Correlations between electrical and structural properties are established.

Isomorphous Substitution of Rare-Earth Elements in Lacunary Apatite Pb8Na2(PO4)6

“…Comparison with our results shows that the data of Laghzizil et al lie in the region of the intrinsic conductivity and the value of E A is in approximate agreement with our result for E A1 . The activation energy found in the alternating-current (ac) conductivity measurements below 600 °C by Brixner and Bierstadt is in agreement with our result for E A2 (Table ), whereas the impedance measurements by Mehnaoui et al . relate to the transitional region between the impurity-controlled and intrinsic conductivity, and this explains why their value of E A is almost twice as much as our result for E A2 .…”

“…The results on the activation energy obtained in the studies 30,43 of the ionic conduction in Pb 8 Na 2 (PO 4 ) 6 by complex impedance spectroscopy are also presented in Table 6.…”