REMOVING HYDROXYPROPYL METHYLCELLULOSE SIZING FROM SAPPHIRE FIBERS BYULTRAVIOLET OZONE CLEANING

Ceramic-fiber-reinforced metallic and intermetallic matrix composites require well-characterized fiber/matrix interfaces. These interfaces r equire that the fiber surface be clean prior to the formation of a com posite or application of a fiber coating. This work investigates the e ffectiveness of ultraviolet (UV)/ozone exposure at removing hydroxypro pyl methylcellulose sizing from sapphire plates and fibers. The surfac e cleanliness was characterized using X-ray photoelectron spectroscopy (XPS). It was found that UV/ozone exposure removed the hydroxypropyl methylcellulose sizing from the plates and fibers but did not remove i norganic species contained in the coating or on the sapphire surface. These inorganic species were readily removed with a water/methanol rin se, providing a clean sapphire surface for incorporation into a compos ite.