Tetra-Boron Carbide (B4C) are an excellent material for industrial applications in the nuclear, aerospace, and military. It is an excellent neutron absorber for use as a radiation shield. Using B4C as thermal barrier coating reduces the metal surface temperature, shields the substrate metal alloy from excessive heat, and increases system efficiency. In this degraded has been evaluated using non-destructive techniques that are appropriate for the predicament. To track the thermal barrier coating's integrity over time, a microwave non-destructive technique was used to predict the porosity of the topcoat. Network analyzer (ENA5701C) in X-band (12-18 GHz) was utilized for this investigation. Detection was based on the changes in the electromagnetic properties, such as permittivity. A set of samples contained varied filler ranging of 5, 10, 15, 20 percent particle reinforcement. Most tested samples shows that porosities have maximum permittivity in the range of 15.4 - 16.7 GHz where some resonance occurred when real permittivity represent the capability ofB4C to store and dissipate energy. This study suggesting that the proposed methodology could be a valuable aid technique for evaluating degraded on composite material systems in a non-destructive and accurate manner with complex pore morphology. © 2022 Trans Tech Publications Ltd, Switzerland.