Densification and oxidation behavior of spark plasma sintered Hafnium Diboride-Hafnium Carbide composite

Journal Article · Mon Mar 02 00:00:00 EST 2020 · Ceramics International

DOI:https://doi.org/10.1016/j.ceramint.2020.02.263· OSTI ID:1801165

Young, Catalina ^[1]; Zhang, Cheng ^[1]; Loganathan, Archana ^[1]; Nautiyal, Pranjal ^[1]; Boesl, Benjamin ^[1]; Agarwal, Arvind ^[1]

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1. Florida International Univ. (FIU), Miami, FL (United States)

This study reports on the sintering and oxidation behaviors of Hafnium Diboride (HfB₂) and Hafnium Carbide (HfC) based ultra-high temperature ceramic (UHTC) composites. Pure Hafnium Diboride, Hafnium Carbide, and HfB₂-50 vol% HfC composite were consolidated using spark plasma sintering (SPS) without the use of sintering aids. HfB₂-HfC composite displayed a high sintered density of 98% as compared to 87% density of pure HfB₂. The increased density of the HfB₂-HfC composite is attributed to the bimodal powder distribution, which allowed for the smaller HfC particle to occupy the voids between the larger HfB₂ particles resulting in improved packing efficiency. Moreover, the higher planar surface energy, for the (111) and the (200) planes for HfC, contributed to the smaller HfC particle being a significant driving force in the sintering process. Oxidation studies of each material were carried out by exposing them to a high-speed plasma jet in a temperature exceeding 2700 °C. The results of these studies show an improved oxidation resistance of HfB₂-HfC composite by 54% and 70% over pure HfC and HfB₂, respectively. The enhanced oxidation behavior is attributed to B₂O₃ filling in the porosity between the HfO₂ scale and protecting the underlying material. This study provides a new alternative to improve the sinterability of UHTC diborides by introducing another UHTC (i.e., HfC) to form a fully dense composite without sintering aid and superior oxidation resistance.

• Research Organization: Univ. of Texas at El Paso, TX (United States); Florida International Univ. (FIU), Miami, FL (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0003865
• OSTI ID: 1801165
• Alternate ID(s): OSTI ID: 1618353; OSTI ID: 1958092
• Journal Information: Ceramics International, Vol. 46, Issue 10; ISSN 0272-8842
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
hafnium diboride
hafnium carbide
spark plasma sintering
plasma jet oxidation
bimodal powder packing