Gas turbine component having thermal barrier coating and a gas turbine using the component

Abstract

The present invention provides gas turbine components having durability and reliability for use in a corrosive environment such as a turbine employing a low grade fuel, and also provides a gas turbine equipped with the components. One of the components is a gas turbine bucket/nozzle comprising a substrate made from an alloy containing Ni, Co, or Fe, a bonding layer made from an alloy and disposed over the substrate, and a thermal barrier coating disposed over the bonding layer. The thermal barrier coating includes a thermal barrier layer of porous ceramics, an environmental barrier layer containing silica, and an impregnation layer having a silica-containing material in the pores of the porous ceramics.

1 . A gas turbine bucket/nozzle comprising a substrate made from an alloy containing Ni, Co, or Fe, a bonding layer made from an alloy disposed over the substrate, and a thermal barrier coating disposed over the bonding layer;
 wherein the thermal barrier coating includes:   a thermal barrier layer of porous ceramics;   an environmental barrier layer containing silica; and   an impregnation layer having a material containing silica in the pores of the porous ceramics.   
     
     
         2 . A gas turbine bucket/nozzle according to  claim 1  that is used in a corrosive environment of molten salt employing low grade fuels. 
     
     
         3 . A gas turbine bucket/nozzle according to  claim 1 , wherein the thermal barrier layer is made from zirconia. 
     
     
         4 . A gas turbine bucket/nozzle according to  claim 1 , wherein the thickness of the environmental barrier layer is from 0.05 to 0.1 mm. 
     
     
         5 . A gas turbine bucket/nozzle according to  claim 1 , wherein the porosity of the environmental barrier layer is 5% or less. 
     
     
         6 . A gas turbine bucket/nozzle according to  claim 1 , wherein the thickness of the thermal barrier layer is from 0.1 to 1 mm. 
     
     
         7 . A gas turbine bucket/nozzle according to  claim 1 , wherein the porosity of the thermal barrier layer is within a range from 10 to 30%. 
     
     
         8 . A gas turbine bucket/nozzle according to  claim 1 , wherein the thickness of the impregnation layer is from 0.01 to 0.1 mm. 
     
     
         9 . A gas turbine bucket/nozzle according to  claim 1 , wherein the environmental barrier layer is a layer formed by using a solution containing a silica precursor. 
     
     
         10 . A gas turbine bucket/nozzle according to  claim 1 , wherein the bonding layer is of a MCrAlY alloy or MCrAl alloy (in which M represent at least one of Fe, Ni, and Co), and the porous ceramics is of partially stabilized zirconia. 
     
     
         11 . A gas turbine combustor having a substrate made from an alloy containing Ni, Co, or Fe, a bonding layer made from an alloy and disposed over the substrate, and a thermal barrier coating disposed over the bonding layer,
 wherein the thermal barrier coating contains:   a thermal barrier layer of porous ceramics;   an environmental barrier layer containing silica;   an impregnation layer having a material containing silica in the pores of the porous ceramics.   
     
     
         12 . A gas turbine shroud having a substrate made from an alloy containing Ni, Co, or Fe, a bonding layer made from an alloy and disposed over the substrate, and a thermal barrier coating disposed over the bonding layer,
 wherein the thermal barrier coating contains:   a thermal barrier layer of porous ceramics;   an environmental barrier layer containing silica;   an impregnation layer having a material containing silica in the pores of the porous ceramics.   
     
     
         13 . A gas turbine comprising any of the bucket/nozzle according to  claim 1 , the combustor according to  claim 11 , and the shroud according to  claim 12 .