1.Visible mechanical impurity is not allowed inside the powder; 2. No remains through Screen 200 mesh/cm; 3. Density: d≤3.7g/cm3; 4. Median particle diameter: D50≤6.0μ; 5. Relative brightness: ≥100%; 6. Main peak wavelength of the emitting spectrum: 450nm, semi-width of the spectrum band 50nm; 7. Color coordinate: x=0.145, y=0.062.