A thermal barrier protected nickel based or cobalt based superalloy component for use in a gas turbine engine includes a thermal barrier coating system having a multi-layered structure. The first bondcoat layer of the thermal barrier coating system comprises a chemical vapor deposited, platinum modified diffusion aluminide layer on the superalloy component (substrate). The diffusion aluminide layer includes an inner diffusion zone proximate the substrate and an outer layer region comprising a platinum modified (platinum-bearing) intermediate phase of aluminum and at least one of nickel and cobalt depending on the superalloy composition. The intermediate phase is a non-ordered solid solution having a range of compositions and is free of other phase constituents. The intermediate phase has an average aluminum concentration in the range of about 18 to about 28% by weight, an average platinum concentration in the range of about 8 to about 35% by weight, and an average nickel concentration in the range of about 50 to 60% by weight and is non-stoichiometric relative to intermetallic compounds of aluminum and nickel, aluminum and cobalt, and aluminum and platinum. An adherent alpha alumina layer is thermally grown on the diffusion aluminide layer and receives an outer ceramic thermal barrier layer deposited thereon.