Thermoreversible gelcasting: A novel ceramic processing technique

A new ceramic processing method, thermoreversible gelcasting (TRG), has been developed. The method uses a gelation process that can be reversed multiple times. Two Al_2O_3 systems have been explored with the use of a specific triblock copolymer to form a binding gel network. The mixture becomes a free-flowing liquid on heating above 60°C. However, on cooling below 60°C, the slurry instantaneously transforms to a physical gel. This process can be reversed easily (essentially with an infinite processing time window) while the solvent is present in the system, which is advantageous when trying to produce high-quality dense pieces if initial casting irregularities occur. Near-theoretically dense specimens have been produced with properties consistent with reported values of high-density Al_2O_3

A thermoreversible gelcasting technique for ceramic laminates

An improved thermoreversible gelcasting technique has been developed which affords the direct casting of laminates. A higher boiling point solvent, pentanol, in conjunction with a better dispersant permitted higher solids loading and optimized processing time for the gel. The technique has been demonstrated for Al_2O_3 bilayers of two densities