open access

https://hdl.handle.net/2115/75374

Relationships between Spark Plasma Sintering Temperature and Mechanical Properties of Combustion-Synthesized α- and β-SiAlON

日本語

self-propagating high-temperature synthesis

2015-04

日本金属学会

Journal of the Japan Institute of Metals

79(4)

191-194

Combustion-synthesized Y-α-SiAlON and Ca-α-SiAlON powders have been consolidated by Spark Plasma Sintering (SPS) at 1300-1450℃ for 10 min, and the mechanical properties of the consolidated bulk samples were investigated. XRD analysis revealed that α-SiAlON partially transforms into β-SiAlON during the SPS and a bulk of α/β-SiAlON mixture was obtained. The fraction of β-SiAlON increases with the increase in sintering temperature and the α to β transformation ratio is high for Y-α-SiAlON compared with Ca-α-SiAlON. The hardness of the consolidated bulk increases with sintering temperature and after reaching the peak at 1350℃ the hardness gradually decreases with temperature in both the cases of Y-α-SiAlON and Ca-α-SiAlON. The increase in hardness with temperature arises from increase in density of the sintered body, while the decrease in hardness results from grain growth due to high temperatures. The fracture toughness monotonically increases with temperature and does not show a peak for both SiAlONs, although Y-α-SiAlON always exhibits higher toughness than Ca-α-SiAlON. The higher toughness of the Y-α-SiAlON is attributable to its higher fraction of transformed β-SiAlON, because the elongated shape of β-SiAlON leads to prevention of crack propagation.

学術雑誌論文

Version of Record

0021-4876

1880-6880

AN00062446