OPTIMIZATION OF NASICON COMPOSITION FOR NA+ RECOGNITION

Na1+xZr2SixP3-xO12 are ceramic materials which are fast ionic conducto rs by Na+. The present work concerns the characterizations of such mat erials in the range x = 1.4-3.0 for their use as ion sensitive membran es. Samples were prepared by sol-gel route to obtain pellets with a hi gh density. Characteristics, such as lattice parameters and bulk condu ctivity are given. Results on detection limit and selectivity of such membranes used in ISE devices are presented. The effect of the stoichi ometry on electrochemical characteristics is discussed. The best perfo rmances are obtained for x = 2.0-2.2, with samples sintered at 1200 de grees C. No influence of sintering temperature is noticeable for the s electivity, excepted for proton which is less interfering after sinter ing at 1200 degrees C. (C) 1997 Elsevier Science S.A.