Surface Modification by Oxide Particles Spray Burner

Abstract

The effect of the sintering characteristics of silica and titania particles on surface modification was investigated experimentally. The turbulent premixed burner, in which hexamethyl disiloxane (HMDS) or titanium tetraisopropoxide (TTIP) diluted with isopropyl alcohol (IPA) was sprayed, were used to feed silica or titania particles on the base material. According to the observation by SEM, the silica particles were agglomerates of small primary particles, whereas the titania particles had spherical shape under the same burner condition. Additionally, the coverage ratio of silica was larger than that of titania. The difference in the shape of those particles was due to the difference in the characteristic sintering time between silica and titania; the characteristic sintering time of titania was smaller than that of silica by 2-4 orders of magnitude. The result of the adhesive strength test showed that the adhesive strength was enhanced by 3-4 times at the maximum with HMDS. However, the excess surface particles after surface was saturated reduced the strength, therefore, there was an optimal condition for the spray time and the spray mass concentration. With TTIP, the adhesive strength was not so enhanced compared with HMDS, which was due to the spherical shape of titania particles that resulted in poor absorption on the base.