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Elevated temperature electrical resistivity measurements of zirconium diboride using the van der Pauw Method
Author(s) -
Neuman Eric W.,
Harrington Gregory J. K.,
Hilmas Gregory E.,
Fahrenholtz William G.
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16636
Subject(s) - van der pauw method , electrical resistivity and conductivity , materials science , ceramic , sintering , composite material , zirconium , zirconium diboride , metallurgy , hot pressing , mineralogy , hall effect , electrical engineering , chemistry , engineering
A novel electrical testing assembly was designed, fabricated, and validated to allow elevated temperature electrical resistivity measurements using the van der Pauw method up to 2173 K. The assembly consisted of h‐BN insulators, ZrB 2 ‐based fixture components, and W signal wires. The assembly was installed in a refractory metal element furnace for temperature control and an oxygen gettering system was utilized to control the oxygen activity of the process gas. The system was validated using high‐purity Mo as a reference standard, demonstrating good agreement with accepted electrical resistivity values for Mo. The system was utilized to measure the electrical resistivity of a ZrB 2 ceramic that was produced from commercially available ZrB 2 powder using C and ZrH 2 as sintering aids and densified by hot‐pressing at 2423 K. The resulting ZrB 2 ceramic was ~96% dense with ~0.2 wt.% ZrO 2 secondary phase and a grain size of ~40 µm. Electrical resistivity of ZrB 2 was measured from room temperature to 2133 K. The electrical resistivity of the ZrB 2 exhibited distinct linear behavior with respect to temperature, increasing from 7.3 µΩ‐cm at 298 K to 35.7 µΩ‐cm at 1223 K (~0.031 µΩ‐cm/K), and then further increasing to 76.0 µΩ‐cm at 2133 K (~0.044 µΩ‐cm/K). To the knowledge of the authors, these measurements were performed at the highest temperatures ever reported using this method.