Ex Parte Ackerman et al - Page 5


                  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.                                                             



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