For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The res...For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The research of the complex aluminates ZnSrA104 （Ln = Nd, Gd, Dy） solid-state process demonstrated the change of the formation mecha- nism among LnSrA104 （Ln = Nd, Gd, Dy） series from DySrA104 oxide. The performed analysis provided a possibility to realize why chemists couldn＇t get DySrA104 for a long period of time.展开更多
NdCoO_(3)nanocrystals formed via glycine-nitrate combustion method followed by heat treatment has been systematically studied.Formation of NdCoO_(3)nanocrystals with minimal size of 7-10 nm from X-ray amorphous combus...NdCoO_(3)nanocrystals formed via glycine-nitrate combustion method followed by heat treatment has been systematically studied.Formation of NdCoO_(3)nanocrystals with minimal size of 7-10 nm from X-ray amorphous combustion products has been elucidated to be a very rapid process,occurring at the temperature of 550-600℃for5-30 min.The comparison of the minimum sizes of NdCoO_(3)crystallites obtained from the offered empirical relation dmin=lunit cell·N(where N is 7-12 and‘unit cellis elementary cell parameter)and the data determined on the basis of X-ray diffraction(XRD)and transmission electron microscopy(TEM)showed good correlation.The existence of special nanoporous microstructure and spatial limitations prevent NdCoO_(3)particle growth.The kinetic equation based on Avrami-Erofeev nucleation model was offered to be correlated well with experimental data of fractional conversion(a)versus isothermal time(s).The apparent activation energy(Ea=(338±32)kJ)of formation of NdCoO_(3)nanocrystals from X-ray amorphous combustion products obtained in excess of oxidant followed by heat treatment at 550-600℃was determined.展开更多
文摘For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The research of the complex aluminates ZnSrA104 （Ln = Nd, Gd, Dy） solid-state process demonstrated the change of the formation mecha- nism among LnSrA104 （Ln = Nd, Gd, Dy） series from DySrA104 oxide. The performed analysis provided a possibility to realize why chemists couldn＇t get DySrA104 for a long period of time.
文摘NdCoO_(3)nanocrystals formed via glycine-nitrate combustion method followed by heat treatment has been systematically studied.Formation of NdCoO_(3)nanocrystals with minimal size of 7-10 nm from X-ray amorphous combustion products has been elucidated to be a very rapid process,occurring at the temperature of 550-600℃for5-30 min.The comparison of the minimum sizes of NdCoO_(3)crystallites obtained from the offered empirical relation dmin=lunit cell·N(where N is 7-12 and‘unit cellis elementary cell parameter)and the data determined on the basis of X-ray diffraction(XRD)and transmission electron microscopy(TEM)showed good correlation.The existence of special nanoporous microstructure and spatial limitations prevent NdCoO_(3)particle growth.The kinetic equation based on Avrami-Erofeev nucleation model was offered to be correlated well with experimental data of fractional conversion(a)versus isothermal time(s).The apparent activation energy(Ea=(338±32)kJ)of formation of NdCoO_(3)nanocrystals from X-ray amorphous combustion products obtained in excess of oxidant followed by heat treatment at 550-600℃was determined.
