Flash sintering of a three‐phase alumina, spinel, and yttria‐stabilized zirconia composite

Journal Article · Sun Apr 09 00:00:00 EDT 2017 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/jace.14818· OSTI ID:1400834

Kok, David  ^[1]; Jha, Shikhar Krishn ^[2]; Raj, Rishi ^[2]; Mecartney, Martha L. ^[1]

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1. Department of Chemical Engineering and Material Science University of California Irvine California
2. Department of Mechanical Engineering University of Colorado at Boulder Boulder Colorado

Abstract Three‐phase ceramic composites constituted from equal volume fractions of α‐Al ₂ O ₃ , MgAl ₂ O ₄ spinel, and cubic 8 mol% Y ₂ O ₃ ‐stabilized ZrO ₂ (8 YSZ ) were flash‐sintered under the influence of DC electric fields. The temperature for the onset of rapid densification (flash sintering) was measured using a constant heating rate at fields of 50‐500 V/cm. The experiments were carried out by heating the furnace at a constant rate. Flash sintering occurred at a furnace temperature of 1350°C at a field of 100 V/cm, which dropped to 1150°C at a field of 500 V/cm. The sintered densities ranged from 90% to 96%. Higher electric fields inhibited grain growth due to the lowering of the flash temperature and an accelerated sintering rate. During flash sintering, alumina reacted with the spinel phase to form a high‐alumina spinel solid solution, identified by electron dispersive spectroscopy and from a decrease in the spinel lattice parameter as measured by X‐ray diffraction. It is proposed that the solid solution reaction was promoted by a combination of electrical field and Joule heating.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐NE0000711
• OSTI ID: 1400834
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Vol. 100 Journal Issue: 7; ISSN 0002-7820
• Publisher: Wiley-Blackwell
• Country of Publication: United States
• Language: English