Synthesis of ceramic powders by using lamellar silica as precursor

In this work, it is shown that, by using lamellar silica samples and metal chlorides as precursors, homogeneous ceramic powders of the type SiO2-MO, w ith M = Zn, Mn, Ni and Co, can be synthesized. The powders were obtained by dispersion of 2.0 g of lamellar silica powders in 200 cm(3) of a 0.5 mol d m(-3) solution of the respective metal chloride, followed by filtration and calcination at 600 degreesC for 30 min in an oxidizing atmosphere. As veri fied by the mapping of the elements, performed by scanning electron microsc opy and EDX analysis, the powders are chloride free, whereas silicon and M are homogeneously distributed. The M/Si ratio for the calcined samples are 0.93, 1.14, 1.64 and 1.62 for M Zn, Mn, Ni and Co, respectively. The BET su rface areas for the same previous sequence of powders are 33 +/-3, 26 +/-1. 4, 20 +/-0.2 and 43 +/-0.2 m(2) g(-1), respectively. (C) 2001 Elsevier Scie nce B.V. All rights reserved.