Microstructural characterization of a foil crown system

In this study, the microstructural nature of the Renaissance crown system has been characterized in an effort to understand its reported properties and performance. Intergranular cavitation was characteristic of the foil surface. The brazed area joining various pleats was porous and exhibited an equiaxial grain structure. Particles of the interfacial alloy sintered with each other and bonded to the foil. Flow of porcelain into intergranular grooves of the foil and within the porous interfacial alloy network was observed. Tags that formed as a result contributed to the micromechanical retention of porcelain on the foil. No evidence of foil-porcelain chemical bonding was found, nor was there any indication of substantial interlayer diffusion.