Organic crystals: More than simple additives toward better electroceramic materials

Abstract

Roles of various organic crystals (OC), notably those containing nitrogen, on the preparation and properties of source materials for electroceramics are featured from the author's own experimental studies. When OC are intimately mixed with metal salts like carbonates, their decomposition is accelerated, liberating the diffusing species at temperatures lower than usual. Mixing of OC with metal oxides under mechanical stressing results in anion exchange and eases diffusion of guest species. Case studies on 3 categories, i.e. i) substitution of oxygen in titania with nitrogen and introduction of oxygen vacancies during co-grinding titania with urea, glycine and/or polytetra fluoroethylene; ii) increase in the rate of reaction of barium titanate formation via a solid state route by OCs with detailed process analysis with glycine as an example of OC, and iii) phase pure solid state synthesis of Li4Ti5O12 by mechanically activating the intermediate, Li2TiO3 with 3 amino acids as OCs.

Hallmarks of mechanochemistry: from nanoparticles to technology

“…Mechanical stressing on organic compounds in the presence of metal oxides (MOs) results in various unusual interactions and alters the properties of both parties. 728 An example is given below in the case of immobilization of drugs by milling with silica nanoparticles. 729 As indomethacin (IM) was co-ground with silica nanoparticles, bridging bonds were formed.…”