SHS in the Ta_Zr_Si_B system and properties of the produced ceramics

International Conference on Synthesis and Consolidation of Powder Materials

Vorotilo, S.^1 ; Levashov, E.A.^1

National University of Science and Technology, MISIS, Leninskii 4, Moscow

119049, Russia^1

关键词: Combustion products;    Combustion waves;    Combustion zones;    Gas-phase mass transfer;    Relative density;    Secondary structure formation;    Structure and properties;    Structure formations;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/558/1/012054/pdf
DOI  :  10.1088/1757-899X/558/1/012054

来源: IOP

【 摘 要 】

In this work, we investigated the macrokinetic parameters of combustion of the Ta-Zr-Si-B mixtures, the mechanisms of phase and structure formation in the combustion wave, and the structure and properties of the consolidated combustion products. During the combustion, primary grains of ZrB2 and TaB2 are formed in the preheating zone due to the gas-phase mass transfer mechanism, which involves the evaporation of boron oxide and chemisorption of boron onto the surface of metals. Upon reaching the combustion zone, the Si-B eutectic and Zr particles melt, and crystals of ZrB2, TaB2, TaSi2 and ZrSi2 precipitate from the melt. In the secondary structure formation zone, unreacted boron interacts with the ZrSi2 and produces ZrB2. TaB2 and ZrB2 partially interact and form solid solution (Ta,Zr)B2. Ceramics, produced by hot pressing of SHS, posses relative density 95-98% and a specific microgradient grain structure.