A thermal barrier tile (34) with a braze layer (46) co-sintered to a ceramic layer (48) is brazed to a substrate (26) of a component for fabrication or repair of a thermal barrier coating (28) for example on a gas turbine ring segment (22, 24). The tile may be fabricated by disposing a first layer of a metal brazing material in a die case (40); disposing a second layer of a ceramic powder on the metal brazing material; and co-sintering the two layers with spark plasma sintering to form the co-sintered ceramic/metal tile. A material property of an existing thermal barrier coating to be repaired may be determined (90), and the co-sintering may be controlled (93) responsive to the property to produce tiles compatible with the existing thermal barrier coating in a material property such as thermal conductivity.