Hydrophobicity and high-temperature mechanical behaviour of hard and optically transparent nanocomposite Al-Si-N thin films

Nanocomposite Al-Si-N thin films were deposited on SS 304, silicon and quartz substrates through magnetron sputtering. Silicon addition in AlN has transformed the coating structure from a single-phase coating into a nanocomposite structured film. It affected the phase formation and interband electronic transition in the Al-Si-N thin film. XPS study suggests the formation of Al-N, Si-N and composite Al-Si-N phases in the Al-Si-N film. The Urbach energy increases from 535 to 763 meV with addition of Si, for nanocomposite Al-Si-N film. No significant change in hardness and microstructure were observed up to 400 degrees C. The Al-Si-N film showed good hydrophobicity on both SS 304 and quartz substrates along with high hardness values. Low wettability and high strength make them a potential candidate for protective optical coatings as they are optically transparent too.