Why do we study ultra-high purity base metals?

The International Conferences on Ultra High Purity Base Metals, the UHPM series have been held to establish new metals science and to educate young researchers of metals, since 1994. The sixth conference, UHPM-99 was held at the Industrial Technology Institute, Miyagi, located in Sendat, Japan, from May 31(st) to June 4(th) of 1999. Abiko and his co-researchers have presented papers on UHP-metals from the beginning of the UHPM series. In this paper, the history of the research on UHP-metals, UHP-iron and UHP Cr-Fe alloys of his group is reviewed.