Spark plasma sintering of SiAlON nanopowders

• Published in: IOP conference series. Materials Science and Engineering 2011-01, Vol.25 (1), p.12022-6
• Main Authors: Zalite, I, Zilinska, N, Steins, I, Krastins, J
• Format: Article
• Language: English
• Subjects: Crystallization; Dwellings; High temperature; Loose powder sintering; Nanostructure; Plasma sintering; Pressureless sintering; Sialon; Sialons; Sintering; Spark plasma sintering
• ISSN: 1757-899X; 1757-8981; 1757-899X
• DOI: 10.1088/1757-899X/25/1/012022

The spark plasma sintering (SPS) method was used for sintering of different SiAlON nanopowders obtained by the method of plasma synthesis. Almost entirely dense samples were obtained at 1450-1500 °C (the range of α-SiAlONs) and under 1600 °C (the range of α-/β-SiAlONs). Results of research were compared wit that obtained by the method of pressureless sintering. Samples obtained at 1700 °C have similar characteristics, differing only with the time of processing: by the SPS method the sample was obtained during 23 minutes (100 °C/min; 5 min.), but by the pressure-less sintering – during 290 minutes (10 °C/min; 120 min.). Material obtained by the pressure-less sintering contains the phase of α- SiAlON, but samples obtained by the SPS process contain almost only the phase of β- SiAlON and the reason of this effect is a specific crystallization process of nanopowders: firstly at temperatures over 1400 – 1450 °C β- SiAlON is formed and only after this the formation of α- SiAlON occurs over 1500-1550 °C. In the case of SPS process a rapid increase of temperature (100 °C/min) and short dwelling time at high temperatures (5 min.) is the reason, why the transition of β- SiAlON into α- SiAlON does not occur.