THERMAL SPRAY COATINGS AND APPLICATIONS THEREFOR

摘要

This invention relates to coatings for a metal or non-metal substrate comprising (i) a thermal sprayed bondcoat layer applied to said substrate comprising an 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 alloy, Cr comprises from about 15 to about 45 weight percent of said alloy, Al comprises from about 5 to about 30 weight percent of said alloy, and M' comprises from about 0.01 to about 1.0 weight percent of said alloy, said alloy thermally sprayed from a powder having a mean particle size of 50 percentile point in distribution of from about 5 microns to about 100 microns, said bondcoat having a surface roughness of at least 200 micro-inches, and said bondcoat having a thermal expansion of about 6.5 millimeters per meter or less between a temperature of from about 25°C to about 525°C, and (ii) a thermal sprayed ceramic layer applied to said bondcoat layer; wherein said coating has a helium leak rate of less than 6 x 10'6 standard cubic centimeters per second. The coatings are useful for extending the service life under severe conditions, such as those associated with metallurgical vessels' lances, nozzles and tuyeres.