Silicon nitride coating on titanium to enable titanium-ceramic bonding

Failures that occur in titanium-ceramic restorations are of concern to clin icians. The formation of poorly adhering oxide on titanium at dental porcel ain sintering temperatures causes adherence problems between titanium and p orcelain, which is the main limiting factor in the fabrication of titanium- ceramic restorations. To overcome this problem a 1-mu m thick Si3N4 coating was applied to a titanium surface using a plasma-immersion implantation an d deposition method. Such a coating serves as an oxygen diffusion barrier o n titanium during the porcelain firings. The protective coating Mras charac terized in the as-deposited condition and after thermal cycling. Cross sect ions of Ti/Si3N4-porcelain interface regions were examined by various elect ron microscopy methods and by energy dispersive analysis of X-rays to study the Si3N4 film's effectiveness in preventing titanium oxidation and in for ming a bond with porcelain. The experiments have shown that this Si3N4 coat ing enables significant improvement in Ti-ceramic bonding. (C) 1999 John Wi ley & Sons, Inc.