Nb 2 O 5 coating of glass fibres applied by chemical vapour deposition

Abstract

In this study, the chemical vapour deposition (CVD) technique is used to modify the surface of Li₂O–ZrO₂–BaO–SiO₂ glass fibre with Nb₂O₅, using NbCl₅ as the precursor. Glass fibres were coated as follows: without thermal pretreatment but followed by air exposure after the reaction with NbCl₅; without thermal treatment followed by water hydrolysis, with thermal treatment at 300°C for 2 h and air exposure; and finally, with thermal treatment and hydrolysis in water. The best result was obtained with the fibre chemically modified with Nb₂O₅ after heat treatment followed by water hydrolysis. This procedure resulted in fibres coated with a homogeneous layer of Nb₂O₅ without cracks. The fibres were characterised by scanning electron microscopy and energy dispersive X-ray spectroscopy. The fibres were evaluated in the qualitative determination of a mixture of methanol, ethanol and 1-butanol by solid phase microextraction and gas chromatography, yielding better results than those of the fibre coated with Nb₂O₅ prepared by metallo-organic decomposition.