Phase interaction between ZrB2–SiC composite ceramics and oxide melts

Abstract

The paper studies the mechanism of interaction between ZrB2–ZrSi2–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°C 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 μm) layer of ZrO2 and SiO2 oxides forms (depending on the amount of SiC and ZrSi2) and serves as a protective film preventing the composite ceramics from corrosion in the oxide melts. The optimum composition of the ZrB2–ZrSi2–SiC ceramics that can be used as corrosion-resistant in oxide melts is determined.