Formation Mechanism of Eutectic Microstructure for CaHfO<sub>3</sub>/HfO<sub>2</sub>

The mechanism of fine eutectic structure formation for CaHfO3/HfO2 was investigated. CaHfO3/HfO2 eutectic solidification film was prepared using a high-power laser with 1400W. The film preparation was conducted in a furnace at 1300oC. The scanning speed of laser was set to 500 to 2000 mm/s. The scanning speed of the laser was greatly varied to create a solidified film and the intermediate steps of micro-structure formation were observed. The micro-structure morphology immediately after solidification was a structure in which an intermediate phase was surrounded by an HfO2 phase. CaHfO3 phase deposited in dot-like form from the intermediate phase. It was confirmed that the dot-like deposit phase connected through atomic diffusion at high temperatures, ultimately forming a fine lamellar structure. It was confirmed that the fine eutectic microstructure of CaHfO₃/HfO₂ is not formed by competitive growth at the melting point during conventional eutectic solidification, but rather is ultimately formed through repeated phase separation after the solidification.