Abstract
Basing on “ab-initio” calculations, C3N4 was claimed to be an ultra-hard material with a bulk-modulus close to that of diamond. Five different structural varieties were announced: the graphitic form, the zinc blende structure, the α and β forms of Si3N4 and another form, isostructural with the high pressure variety of Zn2Si04.
Using the same strategy as that developed for diamond or c-BN synthesis, it appears that the graphitic form could be an appropriate precursor for preparing the 3D varieties. Two main problems characterize the C3N4 synthesis: (-) the temperature should be reduced in order to prevent nitrogen loss, (-) the reactivity of the precursors should be improved.
Consequently, we have developed a new process using the solvothermal decomposition of organic precursors containing carbon and nitrogen in the presence of a nitriding solvent. The resulting material, with a composition close to C3N4, has been characterized by different physico-chemical techniques.
Key Words: