Nickel-chromium-aluminum composite by electrodeposition
An electrodeposited nickel-chromium-aluminum (Ni–Cr–Al) composite including nickel-chromium metal and aluminum, and alloys or compounds formed by Al, Cr and Ni implemented on turbine components consists of from 2 to 50 wt% chromium, from 0.1 to 6 wt% aluminum, along with a residual balance of nickel, and wherein the Ni–Cr–Al combination is heat-treated to shape an aluminum compound and also to restore materials lost during repair procedures of the turbine components.
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BACKGROUND
High and low pressure turbine components including turbine vanes or airfoils are made of nickel based superalloys. These components are protected against the elevated temperature surroundings by a thermal barrier coating (TBC). From the TBC, a bond coatdisposed between the upper oxide layer and the substrate superalloy stipulates an aluminum reservoir, that furnish aluminum diffusing outwards to form protective .alpha. -Al2O3, an underactive thermally grown oxide (TGO). Thus, the bond coat is crucial forprotecting gas turbine components from high temperature oxidation. Such as aluminum, chromium tends to form dense oxide chromia in a high temperature environment, supplying hot corrosion protection. These components permit the components made from nickel alloysto work nicely in gas turbine engines.
Turbine vanes are occasionally removed from service due to the loss of wall thickness through such repair processes as coating stripping, recoating, grit blast cleaning, and chemical processing which typically remove some base metal and oftenreduce component wall thicknesses under the necessary minimum thickness.
Thinned turbine vanes or airfoils are replaced with new components or scrapped unless the lost wall thickness is restored with the addition of metal materials that have key elements (e.g., Cr and Al) lost through the repair procedures.
Accordingly, it is desirable to restore the lost wall thickness of turbine vanes or airfoils by providing a metal coating layer which includes key components (e.g., Cr and Al) lost during the repair procedures to increase the number of repair cyclesfor the vanes or airfoils.
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