Surface reaction of titanium beryllide with water vapor

摘要

Beryllium is one of the candidate materials for the neutron multiplier in the tritium-breeding blanket. However, there are some problems related to the application of beryllium as a neutron multiplier, which include compatibility with structural materials, tritium inventory and reaction of beryllium with water vapor and oxygen in a LOCA accident. Titanium beryllides such as Be_(12)Ti are known to have advantages over beryllium from the perspectives of higher melting point, lower chemical reactivity and lower swelling. Thus, these materials are promising alternatives of beryllium. The authors investigate here the reaction of titanium beryllides with water vapor at high temperatures, and it is found that Be_(12)Ti is by far more tolerant to water vapor than beryllium. To clarify the high tolerance of Be_(12)Ti to water vapor, the surface of Be_(12)Ti used in the experiment was investigated by means of digital microscope, SEM, XRD and electron spectroscopy for chemical analysis (ESCA). These analyses suggest that some oxidized state of beryllium was formed on the surface of Be_(12)Ti exposed to water vapor. In particular, the results of the ESCA analysis gave some clues to understanding the higher tolerance of Be_(12)Ti to water vapor at high temperatures.