Appeal 2007-0687 Application 10/797,422 1 Hasz further discloses that it has been discovered that degradation of 2 thermal barrier coatings by environmental contaminants that form molten 3 contaminant compositions can be prevented by depositing impermeable 4 barrier coatings on surfaces of thermal barrier coatings. An impermeable 5 barrier coating inhibits the degradation of the thermal barrier coating when 6 in contact with the molten contaminant composition at operating 7 temperatures of the thermal barrier coating. Hasz, col. 2, ll. 45-53. 8 The impermeable barrier coating prevents infiltration or viscous flow 9 of liquid contaminant compositions into thermal barrier coating cracks, 10 openings, and pores. Hasz, col. 2, ll. 54-56. 11 The impermeable coating is a ceramic or metal outer coating, 12 deposited on the outer surface of the thermal barrier coating. Hasz, col. 3, ll. 13 40-42. 14 Impermeable barrier coatings include aluminum oxide. Hasz, col. 3, 15 ll. 45-52. 16 The impermeable barrier coating may be deposited on the thermal 17 barrier coating by coating methods known in the art, such as sol-gel. Hasz, 18 col. 4, ll. 25-27. 19 Spence discloses a method for reducing coke formation on metallic 20 substrates such as fuel contacting components of gas turbines. Spence, col. 21 3, ll. 9-12. 22 Coke deposition is an undesirable side effect caused by the catalytic- 23 thermal degradation of hydrocarbon fuels during their consumption in gas 24 turbine engines. Spence, col. 1, ll. 14-17. 5Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: September 9, 2013