Removing Hydroxypropyl Methylcellulose Sizing from Sapphire Fibers by Ultraviolet/Ozone Cleaning

Abstract

Ceramic‐fiber‐reinforced metallic and intermetallic matrix composites require well‐characterized fiber/matrix interfaces. These interfaces require that the fiber surface be clean prior to the formation of a composite or application of a fiber coating. This work investigates the effectiveness of ultraviolet (UV)/ozone exposure at removing hydroxypropyl methylcellulose sizing from sapphire plates and fibers. The surface cleanliness was characterized using X‐ray photoelectron spectroscopy (XPS). It was found that UV/ozone exposure removed the hydroxypropyl methyl‐cellulose sizing from the plates and fibers but did not remove inorganic species contained in the coating or on the sapphire surface. These inorganic species were readily removed with a water/methanol rinse, providing a clean sapphire surface for incorporation into a composite.