GAS TURBINE COMPONENT HAVING THERMAL BARRIER COATING AND A GAS TURBINE USING THE COMPONENT
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 .