Thermal barrier coating with temperature-following layer
A temperature-following layer may be applied to a surface of components within an internal combustion engine. The temperature-following layer follows the temperature swing of adjacent gases (for example, in a combustion chamber). The temperature-following layer may be applied directly to a substrate, or the temperature-following layer may be an outer layer of a multi-layer thermal barrier coating. The multi-layer thermal barrier coating may include, for example, an insulating layer, a sealing layer bonded to the insulating layer, and a porous temperature-following layer disposed on the sealing layer. The sealing layer is substantially non-permeable and configured to seal against the insulating layer.
1. A multi-layer thermal barrier coating comprising:
an insulating layer;
a sealing layer bonded to the insulating layer, the sealing layer being substantially non-permeable and sealing against the insulating layer; and
a porous temperature-following layer disposed on the sealing layer, the porous temperature-following layer having an exposed edge, the porous temperature-following layer configured to follow a temperature of a gas adjacent to the exposed edge, the porous temperature-following layer being at least 90% porous,
the porous temperature-following layer having a height not greater than 50 microns, the sealing layer having a height not greater than 50 microns, and the insulating layer having a height not greater than 250 microns, the sealing layer being no more than 10% porous.
2. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer being at least 98% porous.
3. The multi-layer thermal barrier coating of claim 2 , the porous temperature-following layer being substantially comprised of nickel.
4. The multi-layer thermal barrier coating of claim 1 , wherein the insulating layer comprises a ceramic material selected from the group consisting of: zirconia, stabilized zirconia, alumina, silica, rare earth aluminates, oxide perovskites, oxide spinels, and titanates.
5. The multi-layer thermal barrier coating of claim 1 , the insulating layer comprising a plurality of hollow round microstructures bonded together.
6. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer comprising a plurality of hollow round microstructures bonded together, the plurality of hollow round microstructures being formed of at least one of a ceramic and a metal, each hollow round microstructure having an outer diameter in the range of 10 to 100 microns.
7. The multi-layer thermal barrier coating of claim 6 , at least a portion of the hollow round microstructures each having an outer wall, the outer wall defining an opening therein, the opening being disposed on an outer side of the porous temperature-following layer.
8. The multi-layer thermal barrier coating of claim 6 , each hollow round microstructure being porous.
9. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer comprising at least one of the following:
a plurality of pillars having a height in the range of 10 to 100 microns, each pillar having a width in the range of 1/1000 to 1/20 of the height, each pillar being substantially straight along its height;
a fibrous structure;
a plurality of first pocket-forming structures forming a plurality of first pockets, the plurality of first pocket-forming structures defining open ends of the first pockets along an outer side of the temperature-following layer;
an open cell honeycomb structure;
a plurality of second pocket-forming structures defining gas-trapping second pockets, wherein the gas-trapping second pockets have open ends; and
a plurality of third pocket-forming structures defining gas-trapping third pockets, wherein the gas-trapping third pockets have open ends, the third pocket-forming structures having portions forming outer walls over the gas-trapping third pockets.
10. A component comprising a metal substrate presenting a surface, and the multi-layer thermal barrier coating of claim 1 being bonded to the surface, the component being one of a piston crown and a valve face.
11. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer comprising a plurality of pillars having a height in the range of 10 to 100 microns, each pillar having a width in the range of 1/1000 to 1/20 of the height, each pillar being substantially straight along its height.
12. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer comprising a fibrous structure.
13. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer comprising a plurality of pocket-forming structures forming a plurality of pockets.
14. The multi-layer thermal barrier coating of claim 13 , the plurality of pockets having open ends.
15. The multilayer thermal barrier coating of claim 14 , the pocket-forming structures defining the open ends of the pockets along an outer side of the temperature-following layer.
16. The multilayer thermal barrier coating of claim 14 , the pocket-forming structures having portions forming outer walls over a portion of the open ends.
17. The multi-layer thermal barrier coating of claim 1 , the porous temperature-following layer comprising an open cell honeycomb structure.