Thermal barrier coating repair compositions and methods of use thereof

A method for repairing a thermal barrier coating, wherein the thermal barrier coating is located on a component and wherein the thermal barrier coating has a damaged region, the method comprising:

• depositing an initial layer onto the damaged region, the initial layer comprising the repair composition comprising:
• a ceramic composition in an amount of from about 40 to about 60 percent by volume of the repair composition;
• a colloidal solution in an amount of from about 15 to about 25 percent by volume of the repair composition;
• an aqueous binder in an amount of from about 5 to about 15 percent by volume of the repair composition;
• an aqueous dispersant in an amount of from about 4 to about 8 percent by volume of the repair composition;
• an aqueous ammonia solution in an amount of from about 5 to about 10 percent by volume of the repair composition;
• wherein the ceramic composition comprises:
• a first population of yttria-stabilized zirconia particles having a mean diameter from about 250 nm to about 1000 nm, in an amount of from about 15 to about 30 percent by volume of the ceramic composition;
• a second population of yttria-stabilized zirconia particles having a mean diameter from about 2 μm to about 10 μm, in an amount of from about 10 to about 25 percent by volume of the ceramic composition;
• and
• a third population of yttria-stabilized zirconia particles having a mean diameter from about 20 μm to about 250 μm, in an amount of from about 50 to about 70 percent by volume of the ceramic composition;
• and wherein the colloidal solution comprises:
• an aqueous solvent in an amount of from about 90 to about 98 percent by volume of the colloidal solution;
• and
• a fourth population of yttria-stabilized zirconia particles having a mean diameter from about 2 nm to about 200 nm, in an amount of from about 2 to about 10 percent by volume of the colloidal solution;
• heat treating the initial layer at a temperature of from about 250° C. to about 600° C.;
• optionally, repeating one or more times a combination of the steps of depositing the initial layer onto the damaged region and heat treating the initial layer at a temperature of from about 250° C. to about 600° C., to thereby form a plurality of initial layers;
• depositing a final layer onto the initial layer or onto the plurality of initial layers, the final layer comprising the repair composition;
• and
• concurrently heat treating the final layer and the initial layer at a temperature of from about 900° C. to about 1400° C., to thereby form a patch, or concurrently heat treating the final layer and the plurality of initial layers at a temperature of from about 900° C. to about 1400° C. to thereby form the patch, wherein the aqueous binder comprises water and a binder selected from the group consisting of poly(alkylene carbonate) copolymer, cellulose binder, poly(vinyl alcohol), and polyethylene glycol.