The Influence of ZrO2 Additions on Al2O3 Evaporation and AlN Crystal Growth by Thermal Nitridation of Al2O3–ZrO2 Pellets. Issue 10 (27th August 2013)

• Record Type: Journal Article
• Authors: You, Yu; Kato, Mikako; Ohtsuka, Makoto; Fukuyama, Hiroyuki; Butt, D.
• Is Part Of: Journal of the American Ceramic Society. Volume 96:Issue 10(2013)
• Page Start: 3054
• Page End: 3060
• Publication Date: 2013-08-27
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.12545
• Languages: English
• ISSNs: 0002-7820

Abstract

<abstract abstract-type="main" id="jace12545-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The effects of ZrO₂ additions to Al₂O₃ were investigated to improve the evaporation rate of Al₂O₃ for bulk AlN crystal growth. The evaporation rate of Al₂O₃ increased concomitantly with increasing ZrO₂ concentration under a nitrogen gas stream at 2223 K. The ZrO₂ was predominantly nitrided. The nitridation of ZrO₂ kept the local oxygen partial pressure high at the pellet surface, which suppressed the nitridation of Al₂O₃. The nitridation of ZrO₂ caused the outward diffusion of ZrO₂ (Zr⁴⁺ and O²⁻) in the pellet, which was accelerated further by the presence of Al₂O₃–ZrO₂ liquid phase in grain boundaries, leading to the prompt formation of ZrN porous layer on the pellet surface. The suppressed nitridation of Al₂O₃ and the formation of porous ZrN layer were the reasons for the enhanced evaporation of Al₂O₃, leading to enhanced bulk AlN growth.</p> </abstract>