Molten-Volcanic-Ash-Phobic Thermal Barrier Coating based on Biomimetic Structure

Volcanic ash is a major threat to aviation safety. The softening/melting temperatures of volcanic ash lie far below typical aero-engine operating temperatures. Thus, molten ash can accelerate the failure of thermal barrier coatings (TBCs). Here, inspired by natural superhydrophobic surfaces (e.g., the lotus leaf), a molten-volcanic-ash-phobic TBC, which provides a large possibility to eliminate molten ash issues of TBCs, is developed. A hierarchically structured surface is first prepared on a (Gd0.9Yb0.1)(2)Zr2O7 (GYbZ) pellet by ultrafast laser direct writing technology, aiming to confirm the feasibility of the biomimetic microstructure to repel molten volcanic ash wetting. Then biomimetic-structured GYbZ TBCs are successfully fabricated using plasma spray physical vapor deposition, which reveals silicate phobicity at high temperatures. The exciting molten-volcanic-ash-phobic attribute of the designed surfaces is attributed to the lotus-leaf-like dual-scale microstructure, emulating in particular the existence of nanoparticles. These findings may be an important step toward the development of next-generation aviation engines with greatly reduced vulnerability to environmental siliceous debris.

Automated summary

Volcanic ash poses a significant threat to aviation safety due to its ability to melt at temperatures lower than those encountered in aero-engine operation, leading to damage to thermal barrier coatings (TBCs). In this study, researchers developed a molten-volcanic-ash-phobic TBC inspired by natural superhydrophobic surfaces, such as the lotus leaf. The TBCs demonstrated resistance to silicate wetting at high temperatures, owing to the lotus-leaf-like dual-scale microstructure, which emulates the presence of nanoparticles. These findings could contribute to the development of next-generation aviation engines with enhanced resistance to environmental siliceous debris.