First evidence of the preformation of an inorganic network in sol-gel processing of lead zirconate titanate, obtained by EXAFS spectroscopy

We report the results of EXAFS spectroscopical investigations on lead zirconium titanium precursors in the sol and gel state. Analysis of the second coordination shell for both the sol and the gel yields the contribution of titanium backscatterers at a mean distance of 3.48 A (sol) and 3.44 A (gel). We draw the conclusion that a uniform composition on a microscopic scale exists in the sol as well as the gel state. In other words, heterocondensation is favoured against homocondensation. This provides a good explanation of the low calcination and sintering temperatures in the sol-gel processing of lead zirconate titanate compared with other preparation techniques.