Conditioning of juvenile glass surfaces by atmospheric microwave plasma treatment

Atmospheric pressure chemical vapour deposition processes (APCVD) are widely applied to hot juvenile glass surfaces, e.g. for on-line flat glass coating with transparent conductive oxides like tin oxides and FTO as well as for improvement of strength in container glass products. The temperature for online coating is limited by the type of glass used, in the case of soda–lime–silica glass to 650–750°C. This is a serious drawback of online processes, particularly with respect to the choice of precursors required to give the necessary high deposition rates of more than 10 nm/s. Reduction of the deposition temperature and increase of the deposition rate can be achieved by utilising plasma conditions. The objective of the present study is conditioning of reactive juvenile glass surfaces by means of an atmospheric pressure microwave plasma process (APMPP) to achieve aging- and moisture-resistant glass surfaces. The paper presents a device for APMPP based on a cavity plasma ignited with microwaves at a frequency of 2·45 GHz. The surface properties of soda–lime–silica glasses treated in a nitrogen plasma is discussed.