Title: Translucent α- and α/β-SiAlON ceramics: study on investigation of the relationship between phase diversity and optical properties

Authors: Suna Avcıoğlu; Semra Kurama

Addresses: Faculty of Engineering, Department of Metallurgy and Materials Engineering, Ondokuz Mayıs University, Samsun, 55139, Turkey ' Faculty of Engineering, Department of Materials Science and Engineering, Eskisehir Technical University, Eskisehir, 26000, Turkey; Faculty of Aeronautics and Astronautics, Eskisehir Technical University, Eskisehir, 26000, Turkey

Abstract: In this study, Dy⁺³, Y⁺³, and La⁺³ doped SiAlON ceramics were fabricated by using spark plasma sintering (SPS) technique. The effects of additive cation, starting composition and processing conditions on the morphological evolution as well as on the phase assembly of SiAlON ceramics were investigated. The influence of phase diversity on the optical properties of SiAlON ceramics was also discussed. Results indicate that the translucent α- SiAlON, α/β-SiAlON ceramics and their in-situ composites with AlNpolytypoids could be successfully obtained. The presence of a high amount of secondary phases such as AlN-polytype and the oxynitride glassy phase has been found to reduce the optical transmission of SiAlON ceramics. The doping of Y⁺³ and Dy⁺³ cations contributed better to the formation of single-phase α-SiAlON than that of La⁺³. Doping SiAlON ceramics with Dy⁺³ cation leads to the formation of relatively homogenised final microstructure. Therefore, higher IR transmission values were observed on Dy-α-SiAlON (42.2%) and Dy-α/β-SiAlON (45.07%) samples.

Keywords: SiAlON; transparent polycrystalline ceramics; dopant; phase composition; SPS; spark plasma sintering; microstructure; optical properties; AlN-polytypoids.

DOI: 10.1504/IJMMP.2020.104609

International Journal of Microstructure and Materials Properties, 2020 Vol.15 No.1, pp.14 - 25

Received: 26 Mar 2019
Accepted: 18 Sep 2019
Published online: 23 Jan 2020 *

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