Jean Gary Pierre Louis

US Patent:

40585921, Nov 15, 1977

Filed:

Jun 30, 1976

Appl. No.:

5/701167

Inventors:

Jean Marie Louis Joseph Quets - White Plains NY

Assignee:

Union Carbide Corporation - New York NY

International Classification:

C01G 4900
C01G 2300

US Classification:

423594

Abstract:

Sub-micron metal oxide powders, such as barium titanate, are prepared by mixing a carbohydrate material with solution of barium and titanium compounds, and in some instances other metal compounds, followed by ignition and calcining of the mixture to give sub-micron size particles of barium titanate loosely held together in friable aggregates. For economic reasons as well as their commercial availability, inorganic chlorides are suitable for use as one or more of the starting compounds. However, the presence of a chloride compound greatly influences the thermal stability of that compound in the mixture and hence its rate of decomposition was found to be slow. Accordingly, after the ignition step any chlorides present in the mixture are removed before calcination. The process provides a means for the direct formation of barium titanate free of unwanted phases and which is chemically pure. Barium titanate can also be prepared as an intimate mixture or as a solid solution with other oxides.