Progress Film Forming Technique by the Aerosol Gas Deposition Method (History, Mechanism and Practical Application)

Abstract

The aerosol gas deposition method (AGD) is a low temperature method. No heating procedure exists in the AGD process during the formation of the AGD films. We can form even ceramic films by using AGD method. However, the mechanism of synthesizing ceramic film has not been made clear. The experimental results indicated that in wet type zirconia powder the film could be formed in the limited conditions of diameter and the specific surface area of powders although in dry-milled zirconia powder all powders used could form the films. At the same experiments we observed the high temperature phase of zirconia in the film and a light emission phenomenon at the deposition site during AGD process. The mechanism is as follows. A source powder is positively charged in an aerosol chamber, carrier gas tubing and a nozzle during transportation. The powder with positive charge induces plasma of carrier gases such as helium gas, nitrogen gas, etc. Then, the ceramic film is formed on a substrate put near side of plasma by active species.