Abstract Scope |
Any oxide ceramic of precise simple or complex composition can be made by the organic steric entrapment method (US Patent number 6,482,387 issued 2002). Cations in precise compositions are mixed in solution with 5 wt% organic polymer such as polyvinyl alcohol (for aqueous solutions) or ethylene glycol or polyethylene glycol oils (for alcoholic, non-aqueous solutions). Four times as many cation valence charges can be bound or mechanically entrapped as there are -OH or C-O-C- “functional groups” in the organic molecules. The resulting oxide powder consists of soft agglomerates of nanoparticles of the correct stoichiometry. The nanoparticle diffusion lengths enable UHT non-oxides such as carbides or nitrides to be fabricated under flowing argon or nitrogen, respectively. Geopolymers are self-assembled, amorphous, nanoparticulate, nanoporous inorganic oxide polymers made under ambient temperatures to form a rigid ceramic which is stable to 1000°C, whereupon it crystallizes. They can be 3D printed and readily scaled up. |