Interface Characterization and Bonding Mechanisms of Cold Gas Sprayed Al Coatings on Ceramic Substrates

This work investigates the adhesion mechanisms associated with cold gas sprayed metallic coatings on ceramic substrates. Aluminum layers were deposited on sintered corundum plates and single-crystalline sapphire substrates with different lattice orientations. Examination of the interface region showed that adhesion was the result of recrystallisation and heteroepitaxial growth. Cold spray aluminum coatings were also deposited on Al₂O₃, AlN, Si₃N₄, and SiC substrates to determine if ionic bonding plays a role in interface formation. For comparison, aluminum coatings produced by physical vapor deposition were also examined.