Name: Phosphorescent Pigment SrAl₂O₄:Eu Powder SR-505
Brand: Coatingsink
SKU: phosphorescent-pigment-sr505
Availability: InStock

Question 1

Why is strontium aluminate (SrAl₂O₄:Eu) preferred over zinc sulfide for long-afterglow phosphorescent coatings?

Accepted Answer

Zinc sulfide (ZnS:Cu) phosphors have been used historically but offer only 30–60 minutes of afterglow above the threshold visibility of 0.32 mcd/m², fade rapidly and degrade under moisture and UV. Europium-doped strontium aluminate (SrAl₂O₄:Eu,Dy) provides afterglow duration of ≥8 hours, initial luminance 10–30× brighter than ZnS:Cu, and excellent stability under UV exposure and ambient humidity. SR-505 requires no radioactive components and complies with EN ISO 17398 and IMO resolution MSC.163 for maritime safety photoluminescent marking.

Question 2

How should phosphorescent pigment be incorporated into a transparent coating without reducing afterglow performance?

Accepted Answer

Use a clear, UV-transparent binder (water-based polyurethane, aliphatic acrylic or epoxy ester) that does not absorb the 290–400 nm excitation range. Pigment loading is typically 20–50% by weight in the wet formulation. Avoid UV absorbers or opaque pigments in the same layer. Apply over a white reflective base coat to maximize luminance. Cure at room temperature if possible, as elevated temperature may affect Eu/Dy dopant distribution. A protective clear topcoat is recommended to prevent moisture ingress, which can hydrolyze the aluminate lattice and reduce afterglow.

Excitation	290–400 nm UV/visible
Emission Peak	~520 nm (green)
Particle Size	20–60 µm
Afterglow Duration	≥8 h (>0.32 mcd/m²)
Initial Luminance (after 10 min excitation)	≥1000 mcd/m²

Phosphorescent Pigment SrAl₂O₄:Eu Powder SR-505

Specifications

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