Sintering Mechanisms and Kinetics for Reaction Hot‐Pressed ZrB2. Issue 8 (8th May 2015)

• Record Type: Journal Article
• Authors: Lonergan, Jason M.; Fahrenholtz, William G.; Hilmas, Greg E.; Lee, W.
• Is Part Of: Journal of the American Ceramic Society. Volume 98:Issue 8(2015)
• Page Start: 2344
• Page End: 2351
• Publication Date: 2015-05-08
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.13544
• Languages: English
• ISSNs: 0002-7820

Abstract

<abstract abstract-type="main" id="jace13544-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Sintering mechanisms and kinetics were investigated for ZrB₂ ceramics produced using reaction hot pressing. Specimens were sintered at temperatures ranging from 1800°C to 2100°C for times up to 120 min. ZrB₂ was the primary phase, although trace amounts of ZrO₂ and C were also detected. Below 2000°C, the densification mechanism was grain‐boundary diffusion with an activation energy of 241 ± 41 kJ/mol. At higher temperatures, the densification mechanism was lattice diffusion with an activation energy of 695 ± 62 kJ/mol. Grain growth exponents were determined to be ~4.5, which indicated that a grain pinning mechanism was active in both temperature regimes. The diffusion coefficients for grain growth were 1.5 × 10⁻¹⁶ cm⁴/s at 1900°C and 2.1 × 10⁻¹⁵ cm⁴/s at 2100°C. This study revealed that dense ZrB₂ ceramics can be produced by reactive hot pressing in shorter times and at lower temperatures than conventional hot pressing of commercial powders.</p> </abstract>