Method for producing a corrosion protection layer for thermal insulation layers made of hollow aluminum oxide balls and glass layer and component as well as material mixture

Abstract

Provided is a special type of corrosion protection for ceramic thermal insulation layers which is produced by joining hollow aluminum oxide particles and an outer glass layer, which is produced; in particular, by thermal treatment.

1 . A process for producing a ceramic layer system having an outer ceramic corrosion protection layer, wherein, at least on a substrate, a metallic bonding layer, at least one ceramic thermal barrier coating on the substrate or on the metallic bonding layer, and an at least aluminum-containing layer are applied to the ceramic thermal barrier coating, which as a result of a heat treatment form aluminum oxide, which forms the outer ceramic corrosion protection layer, where the outer ceramic corrosion protection layer is made at least 50% thinner, wherein, in addition to aluminum: at least one element from the group: boron, germanium, gallium and/or at least one element from the group: zirconium, titanium, tantalum, niobium and/or hafnium is applied and/or oxidized for the outer ceramic corrosion protection layer and a heat treatment is carried out. 
     
     
         2 . A component comprising at least:
 a substrate composed of a nickel- or cobalt-based superalloy, a metallic bonding layer, based on NiCoCrAlY, a ceramic thermal barrier coating for thermal insulation on the substrate, an outer ceramic corrosion protection layer on top of the ceramic thermal barrier coating, which ceramic corrosion protection layer is at least 50% thinner than the ceramic thermal barrier coating and comprises at least aluminum oxide and at least one metal or oxide selected from the group consisting of zirconium, titanium, tantalum, niobium and/or hafnium, and/or at least one element or compound from the group: boron, germanium and/or gallium, for the outer ceramic corrosion layer.   
     
     
         3 . The process as claimed in  claim 1 , wherein the aluminum and the at least one further element for the ceramic corrosion protection layer are applied by means of a slip, vapor deposition or sputtering. 
     
     
         4 . The process as claimed in  claim 1 , wherein a mixture of aluminum and zirconium is applied with a proportion of zirconium being not more than 20% by weight. 
     
     
         5 . The process as claimed in  claim 1 , wherein a metallic powder for the ceramic corrosion protection layer has particle sizes of up to 50 μm. 
     
     
         6 . The process as claimed in  claim 1 , wherein a low-melting, viscous glass is to the aluminum layer, to the aluminum/zirconium layer or to the oxidized layer thereof, by means of a slip. 
     
     
         7 . The process as claimed in  claim 6 , wherein the low-melting, viscous glass comprises silicon oxide. 
     
     
         8 . The process as claimed in  claim 6 , wherein the low-melting, viscous glass comprises additives such as magnesium, calcium, boron and/or sodium. 
     
     
         9 . The process as claimed in  claim 6 , wherein silicon-containing precursors for the glass for the corrosion layer are applied, the silicon-containing precursors being silazane, siloxane or silicone polymers. 
     
     
         10 . The process as claimed in  claim 1 , wherein an outermost glass layer is applied on top of the outer ceramic corrosion layer containing aluminum oxide spheres. 
     
     
         11 . The process as claimed in  claim 1 , wherein the outer ceramic corrosion protection layer is at least 30% thinner than the ceramic thermal barrier coating. 
     
     
         12 . The process claimed in  claim 1 , wherein the outer ceramic corrosion protection layer consists of aluminum oxide and zirconium oxide. 
     
     
         13 . The process as claimed in  claim 1 , wherein the heat treatment is achieved by a first use of the component at high temperatures. 
     
     
         14 . The process as claimed in  claim 1 , wherein the heat treatment is carried out before the use of the component and/or installation of the component in a machine. 
     
     
         15 . The process as claimed in  claim 1 , wherein the outer ceramic corrosion protection layer is not more than 300 μm thick. 
     
     
         16 . The process as claimed in  claim 1 , wherein aluminum and at least one element selected from the group consisting of magnesium, zirconium, tantalum, niobium and/or hafnium is applied and/or oxidized for the ceramic corrosion layer. 
     
     
         17 . The process or component as claimed in  claim 1 ,
 wherein not only aluminum but also at least one element selected from the group consisting of silicon, boron, germanium and/or gallium is applied for the ceramic corrosion protection layer.   
     
     
         18 . The process as claimed in  claim 1 ,
 wherein cerium oxide, lanthanum oxide and/or yttrium oxide are applied or are present in the outer ceramic corrosion protection layer.   
     
     
         19 . A mixture of materials for the process as claimed in  claim 1 , which comprises at least: aluminum and at least one element selected from the group consisting of boron, germanium and/or gallium and/or at least one element from the group consisting of zirconium, titanium, tantalum, niobium and/or hafnium. 
     
     
         20 . The mixture of materials as claimed in  claim 19 , which additionally contains silicon and/or magnesium.