Shaped ceramic eutectic plates grown from the melt and their properties

Abstract

Al2O3–YAG–ZrO2 eutectic ceramic plates 10mm in width, 2.4mm in thickness and 100mm in length were directionally grown by micro-pulling down technique under different growth rate (0.1–1mm/min). The effects of the solidification rate on the crystallographic orientation and microstructure properties were analyzed in considerable detail. The microstructure spacing λ depends on the pulling rate v following the law: λ=7.2v−12 where λ is in µm and v in µm/s. For low growth rate (v<0.25), the ternary eutectic plates had homogeneous and regular microstructures and higher pulling rate heterogeneity in the morphology corresponding to colonies presence. The annealed plates did not undergo chemical reaction but slight grain growth was observed.