Blocking Characteristic of Aerosol Deposited Alumina on Plastics against Liquid

Abstract

Aerosol deposition, based on room temperature impact consolidation (RTIC), can form aluminum oxide films on some of the plastics. However the characteristics of these films are not yet known much. One of the important characteristics of ceramic films on plastics is to block liquid to protect the plastic substrates. This may also give information on the structures of aerosol deposited films on plastics. So blocking characteristic of aerosol deposited aluminum oxide films on polycarbonate plates was evaluated with liquid acetone. Polycarbonate becomes clouded when liquid acetone is poured on. Therefore the state of substrate polycarbonate can show whether the aluminum oxide films effectively blocked the liquid by pouring acetone on the films. The aerosol deposited thin aluminum oxide films could not block acetone, and the whole area covered by acetone becomes clouded. In thicker films the residual stress in the films cause many cracks initiated from attacked points by acetone and frequently aluminum oxide films were peeled off from polycarbonate substrates. When the thickness is over lO~m, the films could block acetone. This suggests the existence of minute pores in the aerosol deposited films on plastic substrates.