The effect of additional ceramic powder on the formation tendency of an amorphous phase in a La55Al25Ni20 alloy was investigated by water quenching of molten alloy. The specimens were 12 mm in diameter and 6 mm thick. In the alloy without ceramic powder, the amorphous phase forms only near the surface of the specimen. By the addition of 6 vol% TiB2 powder, it was possible to produce a homogeneous alloy specimen with amorphous and crystalline phases. In order to analyze the role played by ceramic powder in this process, various kinds of ceramic powder were added. The TiC powder played the same role as the TiB2 powder in this process, but the TiN and ZrB2 powders did not. A crystalline phase about 20 μm thick was observed at the surface of TiB2 in the optical microstructure. By EPMA, this crystalline phase was confirmed to have a composition of poorer La and richer Al, Ni than the matrix phase. Since the crystal preferentially nucleate at the TiB2 surface and grows slowly, the matrix phase would be easily amorphized.
