Pressure–temperature phase diagram of Ta-H system up to 9 GPa and 600 C

Hiroyuki Saitoh, Shigeyuki Takagi, Toyoto Sato, Shin Ichi Orimo

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2 Citations (Scopus)


High-pressure hydrogenation behaviors of pure metals have not been investigated exten-sively, although intense research of hydrogenation reactions under high pressure has been conducted to find novel functional hydrides. The former provides us with valuable information for the high-pressure synthesis of novel functional hydrides. A pressure–temperature phase diagram of the Ta–H system has been determined using the in situ synchrotron radiation X-ray diffraction technique below 9 GPa and 600 C in this study. At room temperature, the phase boundary obtained between distorted bcc TaH~1 and hcp TaH~2 was consistent with the previously reported transition pressure. The experimentally obtained Clapeyron slope can be explained via the entropy change caused by hydrogen evolution from TaH~2.

Original languageEnglish
Article number6719
JournalApplied Sciences (Switzerland)
Issue number15
Publication statusPublished - 2021 Aug 1


  • High pressure and high temperature
  • Phase diagram
  • Synchrotron radiation X-rays
  • Tantalum
  • Tantalum dihydride
  • Tantalum hydride
  • Ta–H


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