We claim:
1. A seal for positioning within a seal slot of a turbomachine formed at least
partially by seal slot surfaces of adjacent components to prevent leakage across a gap
extending between the components, the seal comprising:
a metallic shim defining and outer surface including a sealing surface and a support surface; and
a coating overlying and coupled to at least the sealing surface of the metallic shim and forming an outer surface of the seal for engagement with the seal slot surfaces, the coating operable to conform to surface irregularities of the seal slot surfaces and remain coupled to the metallic shim at a predefined operating temperature and a predefined operating pressure to reduce leakage past the seal and through the gap.
2. The seal as claimed in claim 1, wherein the coating is operable to elastically deform to conform to the surface irregularities of the seal slot surfaces and remain coupled to the metallic shim at the predefined operating temperature and the predefined operating pressure.
3. The seal as claimed in claim 1, wherein the coating is a metallic coating, and wherein the melting temperature of the metallic coating is above the predefined operating temperature.
4. The seal as claimed in claim 3, wherein the predefined operating temperature is at least 1,500 degrees Fahrenheit and the predefined operating pressure is at least 5 psi acting to force the coating against the seal slot surfaces.

5. The seal as claimed in claim 3, wherein the metallic coating is a copper alloy.
6. The seal as claimed in claim 5, wherein the metallic coating is 90 weight percent copper and 10 weight percent aluminum.
7. The seal as claimed in claim 1, wherein the coating is operable to flow to conform to the surface irregularities of the seal slot surfaces and remain coupled to the metallic shim at the predefined operating temperature and the predefined operating pressure.
8. The seal as claimed in claim 7, wherein the predefined operating temperature is at least 750 degrees Fahrenheit and the predefined operating pressure is at least 5 psi acting to force the coating against the seal slot surfaces.
9. The seal as claimed in claim 7, wherein the coating is a glass coating comprising a glass phase and oxides.
10. The seal as claimed in claim 9, wherein the glass phase of the glass coating comprises at least one of silica, boric oxide, phosphorous pentoxide and alumina.
11. The seal as claimed in claim 10, wherein the oxides of the glass coating comprise oxides of at least one of alkali metals, alkaline earth metals and rare earth metals.
12. The seal as claimed in claim 7, wherein the coating is an enamel coating comprising a glass phase and fillers.
13. The seal as claimed in claim 12, wherein the glass phase of the enamel coating comprises at least one of alkali alumino boro phospho silicates and alkaline earth alumino boro phospho silicates.

14. The seal as claimed in claim 13, wherein the fillers of the enamel coating comprise refractory oxide compounds.
15. The seal as claimed in claim 7, wherein the coating is a ceramic coating comprising a crystalline ceramic material.
16. The seal as claimed in claim 1, wherein the surface irregularities of the seal slot surfaces form a surface roughness Ra within the range of 1 micrometer to 12.5 micrometers.
17. The seal as claimed in claim 1, wherein the coating includes a coefficient of thermal expansion (CTE) within 25% of a CTE of the metallic shim.
18. The seal as claimed in claim 1, wherein the predefined operating pressure is within the range of 5 psi and 200 psi acting to force the coating against the seal slot surfaces.
19. A turbomachine comprising:
a first turbine component and a second turbine component adjacent the first turbine component, the first and second turbine components including seal slot surfaces at least partially forming a seal slot extending across a gap between the first and second turbine components; and
a seal positioned within the seal slot and extending across the gap to reduce leakage therethrough, the seal comprising:
a metallic shim including a sealing surface and a support surface; and a coating overlying and coupled to at least the sealing surface of the metallic shim and forming an outer surface of the seal for engagement with

the seal slot surfaces, the coating operable to conform to surface irregularities of the seal slot surfaces and remain coupled to the metallic shim at a predefined operating temperature and a predefined operating pressure to reduce leakage past the seal and through the gap, and wherein the coating comprises:
a metallic coating comprising a copper alloy; a glass coating comprising a glass phase and oxides of at least one of an alkali metals, an alkaline earth metals and a rare earth metals;
an enamel coating comprising refractory oxide compounds and at least one of alkali alumino boro phospho silicates and alkaline earth alumino boro phospho silicates; or
a ceramic coating comprising a crystalline ceramic material.
20. The turbomachine as claimed in claim 19, wherein the coating is a glass coating or an enamel coating, and wherein the coating is operable to flow to conform to the surface irregularities of the seal slot surfaces and remain coupled to the metallic shim at the predefined operating temperature and the predefined operating pressure.