Ceramic coating for corrosion resistance of nuclear fuel cladding

Abstract

Coating used for radioactive fuel or a structural component in radioactive fuel reactors, e.g., nuclear fuel cladding alloys, can include a ternary monolithic coating or multiple layers of one or more layers of TiAlN TiZrN, TiCrN, TiNbN and/or CrN, ZrN, NbN, TiN, TaN, HfN. TiHfN, TaHfN, TaNbN, or mixed combinations and/or CrN, ZrN, NbN, TiN, TaN, Si3N4, and/or HfN. In addition, one or more layers can be comprised of a nitride, oxide, or carbide or mixed combination (i.e., carbonides, oxynitrides, oxycarbides, etc.) from Ti, Al, Zr, Cr, Si, Nb, Hf, or mixed combination (i.e., TiAlC 1-x N x ). The multilayer coating can be doped with a dopant.

1 . A coating system on a substrate used for radioactive fuel or a structural component in a radioactive fuel reactor, the coating system comprising
 a multilayer coating on the substrate including (i) one or more layers including a ternary metal compound, and (ii) a top coat layer that does not include aluminum.   
     
     
         2 . The coating system according to  claim 1 , wherein the multilayer coating includes one or more layers of TiAlN, TiCrN, TiZrN, TiNbN, TiHfN, TaHfN, TaNbN, or mixed combinations and/or CrN, ZrN, NbN, TiN, TaN, Si3N4, and/or HfN, or combinations thereof. 
     
     
         3 . The coating system according to  claim 1 , wherein the multilayer coating includes one or more layers of TiAlN TiZrN, TiCrN, or TiNbN as the ternary metal compound. 
     
     
         4 . The coating system according to  claim 1 , wherein the multilayer coating includes one or more layers of CrN, ZrN, HfN, TaN, NbN, or TiN. 
     
     
         5 . The coating system according to  claim 1 , wherein the top coat layer comprises TiN or CrN. 
     
     
         6 . The coating system according to  claim 1 , wherein individual layers of the multilayer coating have a thickness greater than 0.1 μm. 
     
     
         7 . The coating system according to  claim 1 , further comprising a bond coat on the substrate and the multilayer coating on the bond coat, wherein the bond coat has a thickness of between 0.2 μm to 1.5 μm. 
     
     
         8 . The coating system according to  claim 7 , wherein bond coat comprises Ti, Cr, Zr, Nb and/or another transition metal or alloys thereof. 
     
     
         9 . The coating system according to  claim 1 , wherein the substrate is a nuclear fuel cladding. 
     
     
         10 . The coating system according to  claim 1  wherein the substrate comprises a zirconium-based alloy. 
     
     
         11 . The coating system according to  claim 1 , wherein the multilayer coating includes from 4-20 layers 
     
     
         12 . The coating system according to  claim 1 , wherein the multilayer coating includes one or more TiAlN layers having formula of Ti 1-x Al x N, where x is between about 0.1 and about 0.9. 
     
     
         13 . The coating system according to  claim 1 , wherein at the multilayer coating includes alternating layers of TiCrN and CrN with a top coat layer including CrN. 
     
     
         14 . The coating system according to  claim 1 , wherein at the multilayer coating includes alternating layers of TiAlN and TiN with a top coat layer including TiN. 
     
     
         15 . The coating system according to  claim 1 , wherein at least one of the one or more of layers is doped with one or more dopants. 
     
     
         16 . The coating system according to  claim 15 , wherein the dopant is one or more of Yb, Y, Hf, and/or Zr. 
     
     
         17 . The coating system according to  claim 16 , wherein the dopant is in an amount of from about 0.1 atomic % to about 25 atomic %. 
     
     
         18 . The coating system according to  claim 1 , wherein a total coating thickness falls within a thickness range of 1 micron to 20 microns. 
     
     
         19 . A process for preparing a coating system on a substrate used for radioactive fuel or a structural component in a radioactive fuel reactor, the process comprising applying the multilayer coating of  claim 1  by either a physical vapor deposition (PVD) coating process or chemical vapor deposition (CVD) and its derivatives, or a mixed PVD/CVD system on to radioactive fuel or a structural component used in a radioactive fuel reactor. 
     
     
         20 . The process of  claim 19 , wherein the coating is applied by cathodic arc PVD.