Patent Number: 
Section: claims

1. A method of forming a corrosion resistant boundary on a substrate of a component for use in a water cooled nuclear reactor, the method comprising:providing a zirconium alloy substrate;forming on the zirconium alloy substrate, an interlayer with particles selected from the group consisting of Mo, Ta, W, and Nb; andforming a corrosion resistant layer on the interlayer with particles selected from the group consisting of Cr, a Cr alloy, and combinations thereof;wherein the interlayer is formed by a physical vapor deposition process and the corrosion resistant layer is formed by a cold spray thermal deposition process. 2. The method recited in claim 1 wherein Cr alloy of the corrosion resistant layer comprises one of FeCrAl or FeCrAlY. 3. The method recited in claim 1 wherein the cold spray process comprises:heating a pressurized carrier gas to a temperature between 100° C. and 1200° C.;adding the particles to the heated carrier gas; andspraying the carrier gas and entrained particles at a velocity of 800 to 4000 ft./sec. (about 243.84 to 1219.20 meters/sec.). 4. The method recited in claim 3 wherein the carrier gas is selected from the group consisting of nitrogen (N2), hydrogen (H2), argon (Ar), carbon dioxide (CO2), and helium (He) and combinations thereof. 5. The method recited in claim 1 wherein the physical vapor deposition process is selected from the group consisting of cathodic arc vapor deposition, magnetron sputtering deposition, and pulsed laser deposition. 6. The method recited in claim 1 further comprising, following the formation of the interlayer, at least one of grinding, buffing, and polishing to increase the smoothness of the coating. 7. The method recited in claim 1 further comprising, following the formation of the corrosion resistant layer, at least one of grinding, buffing, and polishing to increase the smoothness of the coating. 8. The method recited in claim 1 wherein the particles forming the corrosion resistant layer are pure chromium particles. 9. The method recited in claim 1 wherein the particles forming the corrosion resistant layer are Cr alloy particles. 10. The method recited in claim 1 wherein the particles forming the corrosion resistant layer are selected from the group consisting of FeCrAl and FeCrAlY particles. 11. The method recited in claim 1 wherein the particles forming the interlayer are Mo particles. 12. The method of claim 1, wherein the thickness of the interlayer is between 100 and 300 microns and the thickness of the corrosion resistant layer is between 100 and 300 microns. 13. A method of forming a corrosion resistant boundary on a substrate of a component for use in a water cooled nuclear reactor, the method comprising:providing a zirconium alloy substrate;forming on the zirconium alloy substrate, an interlayer with particles selected from the group consisting of Mo, Ta, W, and Nb; andforming a corrosion resistant layer on the interlayer with particles selected from the group consisting of Cr, a Cr alloy, and combinations thereof;wherein the interlayer is formed by a cold spray thermal deposition process and the corrosion resistant layer is formed by physical vapor deposition.