| abstract |
Provided are an α-SiAlON activated by Eu, which can realize a higher luminance in a light-emitting device such as a white LED, and also a light-emitting device. The α-SiAlON is represented by the general formula: (M) x (Eu) y (Si) 12-(m+n) (Al) m+n (O) n (N) 16-n (wherein M denotes one or more elements including at least Ca, selected from the group consisting of Li, Mg, Ca, Y and lanthanide elements (except for La and Ce)), and is constituted by an α-SiAlON having Eu in the form of a solid solution. The 50% mean area diameter of primary particles of the α-SiAlON is 5 μm or more, and the ratio of the 50% mean area diameter of primary particles to the 50% mean area diameter of secondary particles of the α-SiAlON is preferably 0.56 or more. A light-emitting device 10 includes a light-emitting light source 12 and a wavelength conversion member 15 , wherein the wavelength conversion member 15 includes a α-SiAlON 18 for absorbing near-ultraviolet to blue light generated by the light-emitting light source 12 to generate yellow to orange light. |