Dispersion strengthened rare earth stabilized zirconia

Abstract

A process for forming a coating on a substrate, such as a turbine engine component, is provided. The process comprises the steps of: providing a first rare earth oxide stabilized zirconia composition; providing a second composition selected from the group consisting of a yttria stabilized zirconia composition, a ceria stabilized zirconia composition, alumina, a chromia-alumina composition, a gadolinia stabilized zirconia composition, and mixtures thereof; blending the first rare earth oxide stabilized zirconia composition with the second composition to form a blended powder; and depositing the blended powder onto the substrate. Articles having the coating formed from the above process are also described.

1 . A process for forming a coating on a substrate comprising the steps of:
 providing a first rare earth oxide stabilized zirconia composition;   providing a second composition selected from the group consisting of a yttria stabilized zirconia composition, a ceria stabilized zirconia composition, alumina, a chromia-alumina composition, a gadolinia stabilized zirconia composition and mixtures thereof;   blending said first rare earth stabilized zirconia composition with said second composition to form a blended powder; and   depositing said blended powder onto said substrate.   
     
     
         2 . A process according to  claim 1 , wherein said first rare earth oxide stabilized zirconia composition providing step comprises providing a yttria and zirconia composition containing a rare earth oxide selected from the group consisting of lanthanum oxide, cerium oxide, praseodyium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and mixtures thereof. 
     
     
         3 . A process according to  claim 1 , wherein said first rare earth oxide stabilized zirconia composition providing step comprises providing a zirconia composition containing a rare earth oxide selected from the group consisting of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and mixtures thereof. 
     
     
         4 . A process according to  claim 1 , wherein said first rare earth stabilized zirconia composition providing step comprises providing a gadolinia stabilized zirconia powder composition. 
     
     
         5 . A process according to  claim 1 , wherein said first gadolinia stabilized zirconia composition providing step comprising providing a composition consisting of 10 to 80 wt % gadolinia, 4.0 to 25 wt % ytrria, and the balance zirconia. 
     
     
         6 . A process according to  claim 1 , wherein said second composition providing step comprises providing a 4.0 to 25 wt % yttria stabilized zirconia. 
     
     
         7 . A process according to  claim 1 , wherein said second composition providing step comprises providing a ceria stabilized zirconia composition consisting of 5.0 to 30 wt % ceria, 0.5 to 5.0 wt % hafnia, and the balance zirconia. 
     
     
         8 . A process according to  claim 1 , wherein said second composition providing step comprises a gadolinia stabilized zirconia consisting of 10 to 80 wt % gadolinium oxide and the balance zirconia. 
     
     
         9 . A process according to  claim 1 , wherein said second composition providing step comprises a gadolinia stabilized zirconia consisting of 10 to 80 wt % gadolinium oxide or other rare earth oxide selected from the group consisting of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and mixtures thereof. 
     
     
         10 . A process according to  claim 1 , wherein said blending step comprises blending said two composition so that said first composition is present in the range of from 50 wt % to 90 wt % and the second composition is present in the range of from 10 wt % to 50 wt %. 
     
     
         11 . A process according to  claim 1 , wherein said blending step comprises blending said two compositions so that said first composition is present in an amount of 80 wt % and the second composition is present in an amount of 20 wt %. 
     
     
         12 . A process according to  claim 1 , wherein said first composition providing step comprises providing said first composition in powder form having a particle size in the range of 5 to 250 microns. 
     
     
         13 . A process according to  claim 1 , wherein said second composition providing step comprises providing said second composition in powder form having a particle size in the range of 5 to 250 microns. 
     
     
         14 . A process according to  claim 1 , wherein said depositing step comprises depositing said powders onto a turbine engine component. 
     
     
         15 . A process according to  claim 1 , wherein said depositing step comprises depositing said powders using a thermal spray technique or an EB-PVD technique. 
     
     
         16 . A process according to  claim 1 , further comprising:
 providing a third powder composition for altering coating microstructure to increase porosity; and   said blending step comprising blending said third powder composition with said first and second compositions.   
     
     
         17 . A process according to  claim 16 , wherein said third powder composition providing step comprises providing a third powder which is a fugitive diluent powder. 
     
     
         18 . A process according to  claim 16 , wherein said third powder composition providing step comprises providing a powder selected from the group of polyester and acrylic resin powders. 
     
     
         19 . A process according to  claim 1 , further comprising depositing a layer of a material selected from the group consisting of yttria stabilized zirconia, alumina, chromia-alumina, silicon carbide, silicon nitride and mixtures thereof on said substrate prior to said blended powder depositing step. 
     
     
         20 . A process according to  claim 1 , further comprising depositing a layer of a material selected from the group consisting of yttria stabilized zirconia, alumina, chromia-alumina, silicon carbide, silicon nitride and mixtures thereof on said deposited blended powder after said blended powder depositing step. 
     
     
         21 . A process according to  claim 20 , further comprising depositing a layer of a material selected from the group consisting of yttria stabilized zirconia, alumina, chromia-alumina, silicon carbide, silicon nitride and mixtures thereof on said substrate prior to said blended powder depositing step. 
     
     
         22 . A process according to  claim 1 , wherein said first rare earth oxide stabilized zirconia composition providing step comprises providing a stabilized zirconia composition which contains from about 10 wt % to 80 wt % of at least one of iridium oxide and scandium oxide. 
     
     
         23 . A process according to  claim 1 , wherein said second composition providing step comprises providing gadolinia stabilized zirconia consisting of 15 wt % gadolinium oxide and the balance zirconia. 
     
     
         24 - 50 . (canceled)