Thermodynamic modeling of amorphous Si–C–N ceramics derived from polymer precursors

摘要: Abstract A thermodynamic model has been developed to rationalize the enhanced persistence of amorphous Si–C–N polymer derived ceramics (PDC). Typically, complex morphology such materials is separated into regions carbon and domains a composition SiC x N y on tie line joining phases Si 3 4 in phase diagram. These have modeled as solution five stoichiometric constituents corresponding short-range ordered i 4− atomic configurations identified PDC structure. Parameters Gibbs energy am-SICN estimated basis available assessments additional assumptions concerning energies Si–N Si–C bonds constituents. The for compared, at temperatures 1300 K ⩽  T  ⩽ 2000 K, with equivalent state composed exclusively phases. This comparison proves an resistance crystallization certain compositions, being agreement experimental evidence.