Oxidation-Resistant Coated Superalloy

Abstract

A coating-substrate combination includes: a Ni-based superalloy substrate comprising, by weight percent: 2.0-5.1 Cr; 0.9-3.3 Mo; 3.9-9.8 W; 2.2-6.8 Ta; 5.4-6.5 Al; 1.8-12.8 Co; 2.8-5.8 Re; 2.8-7.2 Ru; and a coating comprising, exclusive of Pt group elements, by weight percent: Ni as a largest content; 5.8-9.3 Al; 4.4-25 Cr; 3.0-13.5 Co; up to 6.0 Ta, if any; up to 6.2 W, if any; up to 2.4 Mo, if any; 0.3-0.6 Hf; 0.1-0.4 Si; up to 0.6 Y, if any; up to 0.4 Zr, if any; up to 1.0 Re, if any.

What is claimed is: 
     
         1 . An article comprising:
 a Ni-based superalloy substrate comprising, by weight percent: 2.0-5.1 Cr; 0.9-3.3 Mo; 3.9-9.8 W; 2.2-6.8 Ta; 5.4-6.5 Al; 1.8-12.8 Co; 2.8-5.8 Re; 2.8-7.2 Ru; and   a coating comprising, exclusive of Pt group elements, by weight percent: Ni as a largest content; 5.8-9.3 Al; 4.4-25 Cr; 3.0-13.5 Co; up to 6.0 Ta, if any; up to 6.2 W, if any; up to 2.4 Mo, if any; 0.3-0.6 Hf; 0.1-0.4 Si; up to 0.6 Y, if any; up to 0.4 Zr, if any; up to 1.0 Re, if any.   
     
     
         2 . The article of  claim 1  wherein:
 the substrate comprises 0.05-0.7 weight percent Hf. 
 
     
     
         3 . The article of  claim 1  wherein:
 the substrate has a 1800° F. & 45 ksi (982° C. & 310 MPa) rupture life of at least 120 hours. 
 
     
     
         4 . The article of  claim 1  wherein:
 the coating comprises exclusive of Pt group elements, by weight percent: 0.4-0.6 said Hf; 0.2-0.4 said Si. 
 
     
     
         5 . The article of  claim 1  wherein:
 the coating has less than 1.0 weight percent overall said Pt group elements combined. 
 
     
     
         6 . The article of  claim 1  wherein:
 in weight percent exclusive of Pt group elements, the coating has less than 1.0 weight percent individually elements other than said Ni, Al, Cr, Ta, W, Mo, Hf, Si, Y, Zr, and Pt group elements, if any. 
 
     
     
         7 . The article of  claim 1  wherein:
 the substrate also falls within one of the broader ranges of Table VI; and 
 the coating also falls within the associated broader range of Table VII. 
 
     
     
         8 . The article of  claim 7  wherein:
 the coating and substrate fall within the narrower associated ranges. 
 
     
     
         9 . The article of  claim 1  wherein:
 in weight percent the coating has 6.0≤W+Ta≤13.0 or Ta+W≤0.05. 
 
     
     
         10 . The article of  claim 1  wherein:
 in weight percent the coating has 55.0≤Ni+Cr≤67.0 and Ni≤52; and 
 Cr weight percent in the coating is at least the same as Cr weight percent in the substrate. 
 
     
     
         11 . The article of  claim 1  wherein:
 the coating has said weight percent combined of said Y, Hf, Zr, and Si of 0.5-1.5 weight percent. 
 
     
     
         12 . The article of  claim 1  wherein:
 the coating has 3.0-5.8 said weight percent Ta; and 
 the coating has combined contents, if any, of no more than 6.5% by weight Ru, said Ta, and said Re. 
 
     
     
         13 . The article of  claim 1  wherein:
 the coating has less than 0.50 weight percent Ru, if any. 
 
     
     
         14 . The article of  claim 1  wherein:
 the coating has less than 0.50 said weight percent Re, if any. 
 
     
     
         15 . The article of  claim 1  wherein:
 the coating has less than 0.10 said weight percent Re, if any. 
 
     
     
         16 . The article of  claim 1  wherein:
 a ratio of said substrate weight percent Re to said coating weight percent Re, if any, is in excess of 10.0. 
 
     
     
         17 . The article of  claim 1  wherein:
 a SRZ, if any, is less than 0.001 inch (0.025 mm) thick. 
 
     
     
         18 . The article of  claim 1  being a turbine blade. 
     
     
         19 . The article of  claim 1  wherein:
 the substrate is a single crystal alloy. 
 
     
     
         20 . The article of  claim 1  wherein:
 the substrate has a density of 0.315-0.327 pounds per cubic inch (8.72-9.05 g/cm 3 ). 
 
     
     
         21 . The article of  claim 1  wherein:
 the substrate has a creep resistance of at least 50 F (28 C) greater than that of PWA1484. 
 
     
     
         22 . A method for using the article of  claim 1 , comprising:
 heating the article to a temperature of at least 2000 F (1093 C) for at least 400 hours while an SRZ, if any, remains less than 0.002 inch (0.05 mm) thick.   
     
     
         23 . A method for forming an article, the method comprising:
 providing a substrate, the substrate comprising, by weight percent: 2.0-5.1 Cr; 0.9-3.3 Mo; 3.9-9.8 W; 2.2-6.8 Ta; 5.4-6.5 Al; 1.8-12.8 Co; 2.8-5.8 Re; 2.8-7.2 Ru; and   applying a coating material, the coating material comprising exclusive of Pt group elements, by weight percent: Ni as a largest by weight constituent; Ni as a largest content; 5.8-9.3 Al; 4.4-25 Cr; 3.0-13.5 Co; up to 6.0 Ta, if any; up to 6.2 W, if any; up to 2.4 Mo, if any; 0.3-0.6 Hf; 0.1-0.4 Si; up to 0.6 Y, if any; up to 0.4 Zr, if any; up to 1.0 Re, if any.   
     
     
         24 . The method of  claim 23  further comprising at least one of:
 applying a layer of one or more Pt group elements prior to applying the coating material; and 
 applying a ceramic coating after applying the coating material. 
 
     
     
         25 . The method of  claim 23  wherein:
 the applying is PVD. 
 
     
     
         26 . The method of  claim 23  wherein:
 heating the article to a temperature of at least 2000 F (1093 C) for at least 400 hours while an SRZ, if any, remains less than 0.002 (0.05 mm) inch thick. 
 
     
     
         27 . An article comprising:
 a Ni-based superalloy substrate comprising, by weight percent: 4.0-6.0 Cr; 1.0-2.0 Mo; 4.0-6.0 W; 3.0-7.0 Ta; 5.0-7.0 Al; 11.0-13.0 Co; 4.0-6.0 Re; 1.0-3.0 Ru; 0.1-0.5 Hf; and   a coating comprising, exclusive of Pt group elements, by weight percent: Ni as a largest content; 5-11 Al; 3-13 Cr; 9-16 Co; up to 7 Ta, if any; up to 6 W, if any; up to 3 Mo, if any; 0.05-0.7 Hf; 0.1-0.5 Si; up to 0.7 Y, if any; up to 0.7 Zr, if any; up to 1.0 Re, if any.   
     
     
         28 . An article comprising:
 a Ni-based superalloy substrate comprising, by weight percent: 4.0-6.0 Cr; 1.0-2.0 Mo; 4.0-6.0 W; 6.0-7.0 Ta; 5.0-6.0 Al; 11.0-14.0 Co; 5.0-6.0 Re; 2.0-4.0 Ru; and   a coating comprising, exclusive of Pt group elements, by weight percent: Ni as a largest content; 5-11 Al; 3-9 Cr; 9-15 Co; up to 7 Ta, if any; up to 6 W, if any; up to 3 Mo, if any; 0.05-0.7 Hf; 0.1-0.5 Si; up to 0.7 Y, if any; up to 0.7 Zr, if any; up to 1.0 Re, if any.