Thermal protection of the hot-end components of ultra-high-flying vehicles requires the microwave absorption of thermal barrier coating (TBC). In this work, the microwave-absorbing functionalization of LaMgAl₁₁O₁₉ (LMA) TBC was successfully realized by adding FeSiAl (FSA) absorber to the LMA thermal barrier ceramic matrix to adjust electromagnetic parameters. Due to the formation of the layered lamellae structure during atmospheric plasma spraying (APS), LMA–FSA composite TBCs have better electromagnetic wave (EMW) absorbing properties than feed powder. EMW absorption of TBCs is mainly controlled by the magnetic loss, and the natural resonance is the main mechanism of magnetic loss. TBCs exhibit a minimum reflection loss (RL) value of −13.4 dB, and effective absorption bandwidth (EAB) of RL < −10 dB is up to 3.11 GHz at a simulated thickness of 2 mm. Phase and structure stability of the TBCs and microwave absorption property could be relatively well preserved even after heat treatments at 600–1000 °C for 3–50 h. Thermal conductivity of the LMA–FSA composite TBCs with FSA contents of 30–50 wt% are about 2.84–3.05 W·m⁻¹·K⁻¹ at 800 °C. LMA–FSA composite TBCs with heat-resistant, heat-insulation, and EMW absorbing properties might find attractive potential applications in the thermal protection for the light alloy hot-end components in civil and military industry.

Modern aero and stationary gas turbine engines have been designed with much higher compressor-pressure ratios and thrust-weight ratios than earlier models, and these ratios are strongly influenced by the hot-running clearances between the rotating and stationary components. The main benefit of reduction in the clearances is efficiency gains, resulting in lowered fuel consumption and polluting gas emissions, with ecological and economic advantages. However, at these undersized clearances, some rubbing interactions are unavoidable, which can be accommodated by applying Abradable Sealing Coatings (ASCs) on the stationary inner surface. This paper reviews the commercially available abradable materials for thermal spraying at various application positions and temperatures. Emphasis is placed on the abradability and wear mechanisms involved. In addition, considering the tendency of SiC/SiC ceramic matrix composites replacing superalloys as hot section components, the future prospect of ceramic abradables based on Environmental Barrier Coatings (EBCs) in turbine stages is summarized and a new concept of “self-degradable ceramics” based on the corrosive steam environment is proposed for the purpose of high-temperature filler-free abradables.