Optical emission generated by particle impact during aerosol deposition of alumina films

Aerosol deposition (AD) is a ceramic coating process that enables films to be fabricated by microparticle impact at room temperature. The optical emission during AD reported in previous studies is thought to be fracto-emission or triboemission; however, the mechanism has never been investigated in detail. In this study, the optical emission of the electric discharge generated during aerosol deposition of alumina films using He, Ar, and N-2 was measured by optical emission spectroscopy. Each spectrum had peaks corresponding to the emission peaks of the carrier gas and no blackbody radiation characteristics were observed. The emission intensity was proportional to the flux of the kinetic energy of the aerosol particles, which suggested that the emission occurred via fracto-emission during particle impact. The gas temperature remained low at around 300 K, which quantitatively confirmed that AD is a room-temperature process. [GRAPHICS]