United States Patent  [ii] Patent Number: 4,504,522
Kaiser et al.  Date of Patent: Mar. 12, 1985
U.S. Patent Mar. 12,1985 Sheet 1 of3 4,504,522
 METHOD OF MAKING A TITANIUM
DIOXIDE OXYGEN SENSOR ELEMENT BY
CHEMICAL VAPOR DEPOSITION
 Inventors: William J. Kaiser, Farmington Hills; Eleftherios M. Logothetis, Birmingham, both of Mich.
 Assignee: Ford Motor Company, Dearborn, Mich.
 Appl. No.: 589,790
 Filed: Mar. 15,1984
 Int. Q.3 B05D 5/12
 U.S. CI 427/103; 427/101;
427/126.3; 427/125; 427/255.3; 338/34; 73/27
 Field of Search 427/126.3, 126.2, 86,
427/89, 101, 103, 255.3, 123, 125; 338/22 SD,
34; 73/27 R
 References Cited
U.S. PATENT DOCUMENTS
3,650,815 3/1972 Ghoshtagore et al 427/126.3
4,228,128 10/1980 Esper et al 428/98
4,234,542 11/1980 Romine 422/98
4,335,369 6/1982 Taniguchi et al 338/34
OTHER PUBLICATIONS Sakurai et al., Rev. Elect. Comm. Lab., 11,1963, p. 178.
Yokozawa et al., Japan J. of Appl. Phys., 7, 1968, p. 96.
Primary Examiner—Richard Bueker
Attorney, Agent, or Firm—William E. Johnson; Olin B.
A method is disclosed for making a titanium dioxide element which can be used as an oxygen sensing element. The method includes obtaining a substrate for supporting a titanium dioxide film and placing that substrate in a vacuum chamber. A vacuum is drawn on the vacuum chamber and the chamber is heated to a temperature in a range from 400°-700° C. A low pressure carrier gas containing 1-10% by volume of oxygen along with a coating gas formed from an organometallic compound of titanium is flowed over the substrate. The coating gas is one which is heat decomposable into a titanium dioxide coating on the heated substrate. The coating gas and the carrier gas are at a total pressure from 100-200 Pa. The coating gas and carrier gas are flowed over the substrate until a titanium dioxide film of required thickness is built up. After formation of the required thickness of the titanium dioxide film, the substrate is removed from the vacuum chamber and heated to a temperature in a range from 800°-1100° C. for a period of 1-10 hours to transform the film on the substrate to a rutile phase titanium dioxide.
8 Claims, 5 Drawing Figures