| 摘要 |
This invention relates to low thermal expansion bondcoats for thermal barrier coatings, said bondcoats comprising: (i) an inner layer comprising an inner layer alloy of MCrAlM' wherein M is an element selected from nickel, cobalt, iron and mixtures thereof, and M' is an element selected from yttrium, zirconium, hafnium, ytterbium and mixtures thereof, and wherein M comprises from about 35 to about 80 weight percent of said inner layer alloy, Cr comprises from about 15 to about 45 weight percent of said inner layer alloy, Al comprises from about 5 to about 30 weight percent of said inner layer alloy, and M' comprises from about 0.01 to about 1.0 weight percent of said inner layer alloy, said inner layer alloy thermally sprayed from a powder having a mean particle size of 50 percentile point in distribution of from about 5 microns to about 50 microns; and (ii) an outer layer comprising an outer layer alloy of MCrAlM' wherein M is an element selected from nickel, cobalt, iron and mixtures thereof, and M' is an element selected from yttrium, zirconium, hafnium, ytterbium and mixtures thereof, and wherein M comprises from about 35 to about 80 weight percent of said outer layer alloy, Cr comprises from about 15 to about 45 weight percent of said outer layer alloy, Al comprises from about 5 to about 30 weight percent of said outer layer alloy, and M' comprises from about 0.01 to about 1.0 weight percent of said outer layer alloy, said outer layer alloy thermally sprayed from a powder having a mean particle size of 50 percentile point in distribution of from about 30 microns to about 100 microns, and said outer layer having a surface roughness of at least 200 micro-inches; and wherein said bondcoat has a thermal expansion of about 6.5 millimeters per meter or less between a temperature of from about 25° C. to about 525° C.
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