Laser ablated coatings on ceramic fibers for ceramic matrix composites

The newly developed pulsed excimer laser ablation (PELA) thin film coating technique was applied to coating ceramic fibers for ceramic matrix composite applications. The feasibility of this application was demonstrated in the coating of two of the most popular monofilaments, SiC (SCS-0) and sapphire. Several materials, such as graphite, SiC and enstatite (MgSiO₃) were used as coating targets. Single-layer or multiple-layer coatings of these materials were deposited on either SiC or sapphire filaments. The microstructure, stoichiometry and thickness of the coatings were examined using scanning electron microscopy, energy-dispersive spectroscopy and Auger electron spectroscopy. The coatings exhibited a dense and uniform morphology, and the stoichiometry compared well with the targets throughout the coating layer. Although the coating was applied discontinuously on cut filaments, the potential application of the PELA technique for continuous fiber coating has been demonstrated.