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Pressureless Sintering of Luminescent CaAlSiN₃:Eu Ceramics

I. Pricha¹, W. Rossner¹, R. Moos²

¹ Siemens AG, Corporate Technology, Research & Technology Center, Otto-Hahn-Ring 6, 81739 Munich, Germany
² Department of Functional Materials, University of Bayreuth, 95440 Bayreuth

received October 31, 2014, received in revised form December 31, 2014, accepted January 13, 2015

Vol. 6, No. 1, Pages 63-68   DOI: 10.4416/JCST2014-00047

Abstract

CaAlSiN₃:Eu powder compacts were pressureless-sintered in a nitrogen atmosphere between 1400 and 1800 °C. The sintering behavior and the dependence of the luminescence properties on the sintering temperature were investigated. It is shown for the first time that it is possible to sinter CaAlSiN₃:Eu ceramics that efficiently emit light starting from a micrometer-sized phosphor powder optimized for high luminescence efficiency. The maximum densities of the ceramics were achieved at ≥ 1700 °C and are limited to 80 % of the solid-state density owing to inhomogeneities of the powder compacts caused by the applied binder-free dry-pressing procedure. The phase composition of the ceramic specimens as well as the luminescence properties remained unchanged during sintering. These results demonstrate that pressureless sintering is suitable for fabricating CaAlSiN₃:Eu bulk ceramics that can be used for LED applications.

Keywords

CaAlSiN₃:Eu, pressureless sintering, luminescence properties, LED

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