Preparation of ceramic thin films by electrospray of ceramic suspensions

An electrostatic atomization technique has been developed to generate ultra-fine spray of ZrO₂ and SiC ceramic suspensions in a range of a few micrometers with a narrow size distribution. The aim of this work is to generate fine spray of ceramic suspensions for preparation of uniform thin films of these ceramic materials on substrates. Compared to some other thin film deposition techniques, such as chemical vapour deposition (CVD), physical vapour deposition (PVD) and plasma spray (PS) etc. the thin film deposition process using electrostatic atomization is not only cheap but also controllable. Preliminary results have shown that for low throughput atomization, the cone-jet is the most suitable method to produce a fine charged aerosol with a narrow size distribution, which is crucial to produce uniform thin films. It was found that the droplet size of the spray is in the range of a few micrometers with a narrow size distribution and that droplet size and spray current obey theoretical prediction of scaling law. The prepared ZrO₂ and SiC thin films were observed to be homogenous with a particle size less than 10 μm