12039-90-6Relevant articles and documents
Chemical reaction and metallic cluster formation by annealing-temperature control in ZrO2 gate dielectrics on Si
Okabayashi,Toyoda,Kumigashira,Oshima,Usuda,Niwa,Liu
, p. 5959 - 5961 (2004)
Thermal stability of the Zr O2 Zr-silicateSi structure and the Zr-silicide formation were investigated by photoemission spectroscopy depending on the annealing temperature in ultrahigh vacuum. By the annealing below 860 °C, the interfacial layer thickness of the Zr-silicate decreased although the Zr O2 top layer was not affected. The annealing at 860 °C caused the interfacial Zr-silicate layer to disappear. By the annealing above 860 °C, the metallic Zr components appeared and the metallic clusters were formed. High-resolution photoemission spectra have revealed that the clusters consist of a Zr Si2 layer. Valence-band spectra depending on the annealing temperature provide us with the information about the crystallization in the Zr O2 layer.
Sintering mechanisms of zirconium and hafnium carbides doped with MoSi 2
Silvestroni, Laura,Sciti, Diletta,Kling, Jens,Lauterbach, Stefan,Kleebe, Hans-Joachim
, p. 1574 - 1579 (2009)
The microstructure of two pressureless-sintered ultra-high-temperature ceramics, namely ZrC+20 vol% MoSi2 and HfC+20 vol% MoSi2, was characterized by scanning and transmission electron microscopy. With regard to the ZrC-MoSi2/s
A novel preparation of Zr-Si intermetallics by electrochemical reduction of ZrSiO4 in molten salts
Liu, Hongxia,Cai, Yanqing,Xu, Qian,Song, Qiushi,Liu, Huijun
, p. 9969 - 9975 (2015)
A method of controllably preparing Zr-Si intermetallics by the electrochemical reduction of ZrSiO4 and ZrSiO4-SiO2 mixed powders in molten CaCl2-NaCl at 800°C is developed. The final product composition can be controlled by adjusting the molar ratio of Si to Zr in the starting material, and ZrSi, ZrSi2 and their mixture were obtained by this process. The reduction pathway of ZrSiO4 and SiO2 to Zr-Si intermetallics involves several calcium-containing intermediate phases, such as CaSiO3, Ca2SiO4, and calcia-stabilized zirconia (CSZ).
New criteria for the applicability of combustion synthesis: The investigation of thermodynamic and kinetic processes for binary Chemical Reactions
Tan, Xiaoming,Su, Xianli,Yan, Yonggao,Uher, Ctirad,Zhang, Qingjie,Tang, Xinfeng
supporting information, (2021/01/07)
Combustion synthesis is a novel technique that utilizes the exothermic heat of a chemical reaction to maintain the reaction and to rapidly prepare materials. But, hitherto, none of unified criterion for the validation of combustion synthesis has been proposed. Herein, we proposed the conditions need to be met. In terms of kinetics, at the adiabatic temperature (Tad), the diffusion distance of atoms (lTad) within 0.1 s should be larger than the particle size of the reactants(d), that is, lTad≥d. For systems that satisfy Tad/Tm,L≥1(where Tm,L is the melting point of the low-melting point component of the reactants), the presence of a liquid phase significantly increases the atomic diffusion distance from nanometers to tens of microns, making the criterion lTad≥d simplified to Tad/Tm,L≥1 in most situations. In terms of thermodynamics, the system needs to ensure that the reaction components are in an activated state, that is, Tad/Tm,H ≥0.7, where Tm,H is the melting point of the high-melting point component. The criteria for the SHS reactions proposed in this study further improve the theoretical understanding of SHS reactions, and provide guidance for exploring the ultra-fast synthesis of binary and multicomponent compounds.
