High-strength zirconium diboride-based ceramic composites consolidated by low-temperature hot pressing

Shuqi Guo; Yutaka Kagawa

doi:10.1088/1468-6996/13/4/045007

High-strength zirconium diboride-based ceramic composites consolidated by low-temperature hot pressing

Sci Technol Adv Mater. 2012 Sep 5;13(4):045007. doi: 10.1088/1468-6996/13/4/045007. eCollection 2012 Aug.

Authors

Shuqi Guo¹, Yutaka Kagawa²

Affiliations

¹ Hybrid Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan.
² Hybrid Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.

Abstract

Two compositions of ZrB₂-based ceramic composites containing Si₃N₄, Al₂O₃ and Y₂O₃ have been hot-pressed at different temperatures between 1673 and 1773 K for 60 min in vacuum. The densification behavior of the composites was examined during the sintering process. The microstructures of the composites were characterized by scanning electron microscopy, and the crystalline phases were identified by x-ray diffraction. The effects of Al₂O₃ and Y₂O₃ additives on the densification behavior and flexural strength were assessed. A relative density of ∼95% was obtained after sintering at 1723 K or higher temperatures. The microstructures of the composites consisted of (Zr,Y)B₂, α-Si₃N₄ and Y₃(Al,Si)₅O₁₂ phases. The room-temperature flexural strength increased with the amount of additives and approached 1 GPa.

Keywords: high strength; low-temperature densification; oxide additives; silicon nitride; zirconium diboride.