Preceramic Paper-Derived Ceramics

A novel class of preceramic paper may serve as a preform to manufacture lightweight as well as multilayer ceramic products. In this article, we discuss the formation, microstructure, and properties of preceramic papers and their conversion into ceramic materials. Oxide as well nonoxide ceramics were processed into single-sheet, corrugated structures, and multilayer ceramics. A high filler loading and uniform distribution of ceramic fillers involves control of colloidal surface interaction including electrostatic, electrosteric, and mechanical retention. Sintering of an oxide-loaded preceramic paper in air results in highly porous products, with the porosity shape and distribution templated by the pulp fiber used in papermaking. In the case of carbide-loaded paper, dense composite materials are obtained by reactive infiltration processing. Anisotropic properties of machine-fabricated preceramic paper and bonding interfaces in multilayer stacks give rise to anisotropic mechanical properties of the resulting ceramic composites. Noncatastrophic failure was observed when tensile loading stress was applied parallel to the interfaces (in-plane loading). Applying well-established paper processing technologies, including laminated object manufacturing, ceramic structures of complex shape and size can easily be processed, offering a high potential for economical manufacturing.