Chemical vapor deposition of mixed metal oxide coatings

A chemical vapor deposition process for preparing a composite article comprising a thin mixed metal oxide film coating on a substrate, which comprises:

• contacting a heated substrate with (1) an oxidizing gas stream and (2) heat decomposable organometallic compounds yielding on decomposition two or more metals of different groups of the Periodic Table and each selected from the group consisting of metals of Group IIA and transition metals of the Periodic Table, said heat decomposable organometallic compounds being contained in one or more nonoxidizing carrier gas streams, said heat decomposable organometallic compounds including at least one compound of the following formula (I) ##STR6## wherein:
• M.sub.1 is a metal of Group IIA, IIIB, IVB, VB, VIB, VIIB or VIII of the Periodic Table,
• R.sub.1 is a lower alkyl or lower alkenyl radical of 2 to about 6 carbon atoms,
• R.sub.2 is hydrogen, fluoring, a lower alkyl radical of 1 to 6 carbon atoms, or a lower alkenyl radical of 2 to 6 carbon atoms,
• n is the valence of M.sub.1 and is an integer from 2 to 4, and
• p is an integer from 0 to (n-1);
• or a compound of the following formula (II) ##STR7## wherein;
• M.sub.2 is a metal of Group IB of the Periodic Table;
• R.sub.3 is a lower alkyl radical of 1 to about 6 carbon atoms, or a lower alkenyl radical of 2 to about 6 carbon atoms;
• and
• R.sub.4 is a lower alkyl radical of 1 to 6 carbon atoms;
• the temperature of said substrate being from 150.degree. to 1000.degree. C. and above the decomposition temperatures of said organometallic compounds.