Fabrication of amorphous bulk and multi-phase ceramics by melting method in the HfO2-Al2O3-Gd2O3-Eu2O3system

Ceramics have generally been fabricated from powders by shape forming & sintering methods except for glasses and glass ceramics. Glasses and glass ceramics can be fabricated by melting methods. The melting method has not only higher productivity but also higher shape forming ability than powder processes via forming & sintering methods. Thus we have reinvestigated melting methods in binary and ternary oxides systems to fabricate amorphous bulk ceramics and bulk nano composites. We have successfully fabricated amorphous phases by simple melt solidification methods in ternary eutectic melts in the HfO2-Al2O3-Gd2O3system. The present study demonstrates the formation of the amorphous phases in quaternary systems HfO2-Al2O3-Gd2O3-Eu2O3. Furthermore, we have also succeeded to fabricate nano-structured bulk ceramics, which consisted of constituent oxide grains with 20–100 nm in size, by post annealing of the amorphous phase.