Coating of Carbon Materials with Silica by Sol-Gel Method

Abstract

The optimum conditions for silica coating on carbon materials by using an ethanol solution of tetraethoxysilane (TEOS) were studied. A homogeneous film of silica with a thickness of 0.2 pm without any cracks was obtained by dip-coating process under the following conditions; the ethanol solution containing TEOS of 0.1 molg, the pulling-out velocity of the carbon substrates at 2.0 cm/s, the gelation in the air for 48 h, and the heating at 70 °C for 1 h and then up to 1000 °C by 5 °C/min. From the SEM observation of the cross-section of the substrates with silica, it was shown that the silica coating film adhered excellently to carbon substrate.