Thermal Properties of Hf-Doped ZrB₂ Ceramics

Abstract

The effect of Hf additions on the thermal properties of ZrB2 ceramics was studied. Reactive hot pressing of ZrH2, B, and HfB2 powders was used to synthesize (Zr1-x,Hfx)B2 ceramics with Hf contents ranging from x = 0.0001 (0.01 at.%) to 0.0033 (0.33 at.%). Room-temperature heat capacity values decreased from 495 J·(kg·K)-1 for a Hf content of 0.01 at.% to 423 J·(kg·K)-1 for a Hf content of 0.28 at.%. Thermal conductivity values decreased from 141 to 100 W·(m·K)-1 as Hf content increased from 0.01 to 0.33 at.%. This study revealed, for the first time, that small Hf contents decreased the thermal conductivity of ZrB2 ceramics. Furthermore, the results indicated that reported thermal properties of ZrB2 ceramics are affected by the presence of impurities and do not represent intrinsic behavior.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Ceramic materials; Hafnium; Hot pressing; Specific heat; Thermodynamic properties; Capacity value; Hf-doped; Intrinsic behavior; Reactive hot pressing; Thermal conductivity

International Standard Serial Number (ISSN)

0002-7820; 1551-2916

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 Blackwell Publishing Inc., All rights reserved.

Publication Date

01 Sep 2015

Link to Full Text

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