High-Temperature Interaction of Molten Gray Cast Iron with Al2O3-ZrO2-SiO2 Ceramic

Abstract

High-temperature interaction between molten conventional gray cast iron (wt.%: 4.1 C; 1 Si; 0.20 Mn; 0.03 S; 0.04 P, the rest—Fe) and multiphase Al2O3-ZrO2-SiO2 ceramic substrate (wt.%: 51.5 Al2O3, 33.8 ZrO2, 13.3 SiO2, ~ 1 NaO2, 0.15 Fe2O3 + TiO2 + CaO) was examined at a temperature of 1450 °C for 15 min under inert flowing gas atmosphere (Ar, 850-900 hPa) using a sessile drop method coupled with contact heating procedure. Melting, wetting behavior and solidification of gray cast iron sample were continuously recorded with a high-speed high-resolution CCD camera. Under conditions of this study, selected gray cast iron alloy does not wet the Al2O3-ZrO2-SiO2 ceramic forming the final contact angle with average value of θf ~ 135°. The wetting kinetic curve was not smooth and its shape suggests the effect of substrate chemical heterogeneity due to multiphase composition of the substrate material. After the sessile drop test, the solidified drop was easily detached from the ceramic substrate along the drop-side interface showing a lack of bonding between the drop and the substrate. Structural characterization of the drop/substrate couple evidenced the nucleation and growth of graphite at the drop surface and at the drop/substrate interface taken place during solidification and resulting into the formation of discontinuous interfacial graphite layer.