This manuscript presents the microstructure, geometrical product specification, and results of scratch tests performed on the interlayer of thermal barrier coating (TBC) with Rockwell’s intender. The TBC was provided by depositing two layers, metallic interlayer and external ceramic layer, onto a plate coating made of cobalt alloy MARM509 in plasma spraying process. Based on measurements of microhardness made with Berkovitz’s indenter using Nano Scratch-Tester (CSM Instruments), it was stated that elastic (Ee) to total energy (Ec) parameters (MIT = Ee/Ec), γ phase matrix of alloy MAR-M509 (MITγ), metallic interlayer (45% Ni–22% Co–17% Cr–16% Al–0.3% Y) (MITM), and ceramic layer (MITZrO2), are proportion, that is, 0.29:0.22:0.50. The surface of the casting was sandblasted with Al2O3 powder in an air stream before the TBC was introduced. Scratches were made along the cross section from a mould material (MAR-M509) through metallic interlayer and external ceramic layer in the TBC. Friction force, friction factor, and acoustic emission were recorded during the test. It has been proven that metallic interlayer in the TBC of ca. 200 μm thickness forms tough coating without pores with good cohesion values and very good adhesion values to the mould.