PHASE INTERACTION BETWEEN ZrB_2-SiC COMPOSITE CERAMICS AND OXIDE MELTS

摘要

The paper studies the mechanism of interaction between ZrB_2-ZrSi_2-SiC composites and dross-type oxide melts formed during the combustion of low-reactive carbons containing oxide rocks up to 30-40 vol. %. It is established that silicon carbide from the surface layer of the composite interacts with iron oxides to form spherical precipitates of the FeSi_x phase at 1350-1550 in the wetting process and in contact with the dross during 10-50 h. At the composite-dross interface, a thin (7.5-30.0 m) layer of ZrO_2 and SiO_2 oxides forms (depending on the amount of SiC and ZrSi_2) and serves as a protective film preventing the composite ceramics from corrosion in the oxide melts. The optimum composition of the ZrB_2-ZrSi_2-SiC ceramics that can be used as corrosion-resistant in oxide melts is determined.