Phosphor powder, composite, and light-emitting device

A phosphor powder composed of α-sialon phosphor particles containing Eu,

• wherein the α-sialon phosphor particles are composed of an α-sialon phosphor containing an Eu element, represented by General Formula:
• (M1x, M2y, Euz)(Si12−(m+n)Alm+n)(OnN16−n) (provided that M1 is a monovalent Li element and M2 is a divalent Ca element), and in the general formula, x=0, 0<y<2.0, 0<z≤0.5, 0<x+y, 0.3≤x+y+z≤2.0, 0<m≤4.0, and 0<n≤3.0 are satisfied,
• wherein a light emission peak wavelength is equal to or more than 590 nm,
• wherein a volume-based median diameter (D50) determined by a laser diffraction scattering method is equal to or more than 10 μm and equal to or less than 20 μm, and
• a diffuse reflectance with respect to light at a wavelength of 600 nm is equal to or more than 94% and equal to or less than 99%.

A phosphor powder composed of α-sialon phosphor particles containing Eu,

• wherein the α-sialon phosphor particles are composed of an α-sialon phosphor containing an Eu element, represented by General Formula:
• (M1x, M2y, Euz)(Si12−(m+n)Alm+n)(OnN16−n) (provided that M1 is a monovalent Li element and M2 is a divalent Ca element), and in the general formula, x=0, 0<y<2.0, 0<z≤0.5, 0<x+y, 1.5≤x+y+z≤2.0, 0 <m≤4.0, and 0<n≤3.0 are satisfied,
• wherein a volume-based median diameter (D50) determined by a laser diffraction scattering method is equal to or more than 10 μm and equal to or less than 20 μm, and
• a diffuse reflectance with respect to light at a wavelength of 600 nm is equal to or more than 94% and equal to or less than 99%.