The ethylene-diamine-tetra-acetic acid (EDTA)-gel process has been used to
produce carbonates and oxides of the alkaline earth elements Ba, Sr and Ca
and their solid solutions. These materials have a range of potential applic
ations including electron emission and catalysis. Gels of composition Ba-ED
TA, Sr-EDTA, [Ba0.5Sr0.5]-EDTA, [Ba0.5Sr0.45Ca0.05]-EDTA were prepared at p
H 6 from aqueous solutions of the alkaline earth nitrates and EDTA and thei
r thermal decomposition studied by TGA/DSC. The gels and the products deriv
ed from calcination of these gels at different temperatures have been chara
cterised by FTIR, XRD and SEM, and shown to have high chemical homogeneity
and fine particle size. Decomposition of the gels to the carbonate form occ
urred below 300 degrees C with subsequent formation of the oxide occuring o
n heat treatment at temperatures ranging from approximately 800 degrees C t
o > 1000 degrees C depending upon gel composition. The process route is sui
table for the production of particulate materials or porous coatings. (C) 2
000 Kluwer Academic Publishers.