Multilayered coatings with diamond-like carbon

Abstract

Multilayered coatings include an adhesion base layer that can adhere to a metal substrate, and a top surface layer that has a surface roughness of less than or equal to about Ra 0.0254 μm, wherein at least one of the layers comprises a diamond-like carbon.

What is claimed is: 
     
         1 . A multilayered coating comprising:
 an adhesion base layer that can adhere to a metal substrate; and   a top surface layer that has a surface roughness of less than or equal to about Ra 0.0254 μm;   wherein at least one of the layers comprises a diamond-like carbon.   
     
     
         2 . The multilayered coating of  claim 1  further comprising one or more intermediate layers between the adhesion base layer and the top surface layer. 
     
     
         3 . The multilayered coating of  claim 2 , wherein at least one of the one or more intermediate layers is selected from the group consisting of silicon and germanium. 
     
     
         4 . The multilayered coating of  claim 3 , wherein the at least one of the one or more intermediate layers comprising silicon or germanium is from about 0.1 μm to about 0.5 μm thick. 
     
     
         5 . The multilayered coating of  claim 2 , wherein at least one of the one or more intermediate layers is doped diamond-like carbon. 
     
     
         6 . The multilayered coating of  claim 5 , wherein the at least one of the one or more intermediate layers comprising doped diamond-like carbon is from about 5 μm to about 10 μm thick. 
     
     
         7 . The multilayered coating of  claim 2 , wherein the adhesion base layer comprises silicon. 
     
     
         8 . The multilayered coating of  claim 2 , wherein the top surface layer comprises diamond-like carbon. 
     
     
         9 . The multilayered coating of  claim 2 , wherein the multilayered coating comprises at least 10 layers. 
     
     
         10 . The multilayered coating of  claim 1 , wherein the adhesion base layer is selected from the group consisting of silicon and diamond-like carbon. 
     
     
         11 . The multilayered coating of  claim 1 , wherein the top surface layer is selected from the group consisting of silicon carbide and diamond-like carbon. 
     
     
         12 . The multilayered coating of  claim 1 , wherein the at least one of the layers that comprises a diamond-like carbon is from about 5 μm to about 10 μm thick. 
     
     
         13 . The multilayered coating of  claim 1 , wherein the multilayered coating is at least about 20 μm thick. 
     
     
         14 . The multilayered coating of  claim 1 , wherein the multilayered coating has a hardness of at least about 10 GPa. 
     
     
         15 . A coated article comprising:
 a metal substrate comprising an outer surface; and   a multilayered coating covering at least a portion of the outer surface of the metal substrate, wherein the coating comprises:
 an adhesion base layer that can adhere to a metal substrate; 
 a top surface layer that has a surface roughness of less than or equal to about Ra 0.0254 μm; and 
 wherein at least one of the layers comprises a diamond-like carbon. 
   
     
     
         16 . The coated article of  claim 15 , wherein the metal substrate comprises a compressor blade for a turbine. 
     
     
         17 . The coated article of  claim 16 , wherein the compressor blade is a late stage compressor blade. 
     
     
         18 . The coated article of  claim 15  further comprising one or more intermediate layers between the adhesion base layer and the top surface layer. 
     
     
         19 . The coated article of  claim 18 , wherein at least one of the one or more intermediate layers is selected from the group consisting of silicon, germanium, titanium, chromium, nitrogen, fluorine, sulfur and doped diamond-like carbon. 
     
     
         20 . The coated article of  claim 15 , wherein the at least one of the layers that comprises a diamond-like carbon is from about 5 μm to about 10 μm thick.