Enhanced bonding between YSZ surfaces using a gas-phase fluorination pretreatment.

The present investigation focuses on the surface modification, via gas-phase fluorination process, of yttria- stabilized zirconia (YSZ) to increase its wettability and chemical bonding directly to acrylate-based resin cements. YSZ plates and cylinders, as-received and roughened, were pretreated in a fluorine containing plasma and bonded with a commercially available resin cement for simple shear bond adhesion testing. No organo-silane coupling agent was used to enhance bonding between the two substrates. Shear bond tests revealed that bond strength increased with fluorination time. Furthermore, the pretreated, as received (nonroughened) specimen group displayed relatively high bond strengths suggesting surface reactivity and direct chemical bonding with the resin cement. X-ray photoelectron spectroscopy analysis revealed the surface conversion layer to be a mixture of phases; zirconium oxyfluoride, zirconium fluoride, and yttrium fluoride. It is hypothesized that these fluoride and oxyfluoride phases have the potential to increase surface hydroxylation, enabling direct covalent bonding between YSZ and resin cement. It is believed that this surface treatment has broad reaching impact when using high-strength ceramics in a multitude of bioapplications.