Electrostatic deposition of CVD particles for fabrication of ultrafine ceramic filter

A novel method for forming a ceramic membrane was devised. Ultrafine particles of silicon nitride synthesized by thermally activated chemical vapor deposition (CVD) were deposited on an outer wall surface of a porous ceramic tube (substrate) by electrostatic force and sintered in an inert gas atmosphere. The ceramic-made electrode assembly using surface discharge was used for charging ultrafine particles at an elevated temperature. Special ceramic membranes with a three-dimensional network for use as a fiber filter were obtained by this method. The effective pore size was around 0.2-1.0 mu m in diameter, and its porosity was extremely large. This structure has the advantage of allowing microfiltration with a very low pressure drop.<
>