This is an exploration of a new chemical vapor deposition (CVD) process for nanocrystalline metals and ceramic coatings based on the vapor-phase reaction between elemental sodium and metal chlorides or other halogenated species. The relationship between vapor-phase chemistry and the resulting thin films are studied using ex-situ analysis of film properties and use of a CVD model, developed as part of this effort, incorporating chemical kinetics, vapor flow, transport, and nucleation. The effects, and possible control, of salt supersaturations on film morphology are studied. The relationship between gas-phase chemistry and film microstructure for processes involving simultaneous deposition of a metal and ceramic to form a nanocrystalline/amorphous structure is also studied; these products may have properties necessary for a superhard coating.
The new approach studied in this project offers the prospect of new industrial coatings with superior properties and/or a new route to known coatings that is more sound environmentally than current technology.
