Aerosol deposition of dense Al2O3 coatings on patterned substrates

Aerosol deposition (AD) is a promising technique for producing dense nanocrystalline ceramic films at room temperature. AD has attracted attention in the ceramic coating field due to its unique features, including its pure solid-state nature, high film density with crack-free structure, controllable coating thickness, relatively high deposition rate, enhanced mechanical properties, and a wide choice of substrates. Among the numerous process parameters involved in the deposition, substrate roughness seems to have affected the coating quality and particle anchoring behavior directly. Nanocrystalline alumina (α-Al₂O₃) layers have been fabricated in the customized deposition system in this work. To study the effect of substrate roughness, flat and micro-patterned silicon wafers were prepared and used. Microstructural analysis and mechanical property testing indicated the formation of dense and crack-free coatings with great adhesion. The effect of substrate patterning on coating thickness, microstructure features, and the coating growth process was studied.