NIOBATES AND TANTLATED OF ALKALI AND ALKALI EARTH METALS AS SUBSTANCES OF PROTECTIVE SIGNS Russian patent published in 2015 - IPC G07D7/12 C09K11/55 C09K11/78 

FIELD: chemistry.

SUBSTANCE: inventions can be used for verification of authenticity and protection against counterfeit of valuable papers or documents, as well as high-quality goods. Security element contains luminescent substance of general formula B_0.5XO₃:Z, in which B is alkali earth metal, X is Nb and/or Ta, Z is luminescent activator, for instance, rare earth metal with oxidation degree +3, or Ti³⁺, or V⁴⁺, or Cr²⁺, or Cr³⁺, or Cr⁴⁺, or Cr⁵⁺, or Mn³⁺, or Mn⁴⁺, or Mn⁵⁺, or Mn⁶⁺. Atomic ratio B:X = 0.5:1 Main crystal lattice is additionally doped with one or several elements E, which act as luminescence sensitiser, and/or suppress certain emission wavelengths, and/or compensate charges. Luminiscent substance is obtained by mixing oxide, or hydroxide, or carbonate, or peroxide of element B, element X oxide and element Z oxide or carbonate. Mixture is annealed at 900-1200°C for 1-20 h. After that, product can be milled to desirable size of particles, which can be covered with protective coating, for instance of SiO₂. To verify security element authenticity of paper or valuable document, protected against counterfeit, said luminescent substance is excited, thereof-radiated light is registered, its properties are compared with the ones, known for said luminescent substance, with verifying authenticity in case of sufficient correspondence.

EFFECT: increased verification efficiency.

14 cl, 1 dwg, 8 ex