Biomimetic Processing of Ceramic Composites

Abstract

Abstract : Three task areas composed the research effort: (1) optimized depth of photocuring in a resin system, (2) improved resin/ceramic particle compatibilities consistent for use in stereolithography, and (3) developing the technique of ceramic stereolithography (CSL) for the fabrication of a ceramic matrix composite test structure. The depth of photocuring in a model resin system was investigated as a function of photoinitiator concentration. Polymer solutions were photocured using varying levels of energy and photoinitiator concentration. An optimal photoinitiator concentration maximizing the cure depth was observed. Two regimes were shown to exist in which shrinkage was minimized or maximized. A quantitative model was developed to describe the system's behavior. Good agreement with experiment was obtained and the model predicted both the existence and location of the optimal photoinitiator concentration and corresponding cure depth. After optimizing the resin/particle system, complex shaped structures were fabricated from ceramic powder compacts constructed using CSL. The main processing parameters in CSL such as layer thickness, resolution, hatch spacing, and overcure were found to depend on the light propagation in a concentrated dispersion, and a model was developed and used to optimize the fabrication of the ceramic structures.