PERSISTENT PHOSPHORESCENT COMPOSITE MATERIAL

PROBLEM TO BE SOLVED: To provide a persistent phosphorescent ceramic composite material containing two or more phases and being a dense material.SOLUTION: A persistent phosphorescent ceramic composite material is obtained by a step of preparing a mixture of metal oxides and a phosphorescent substance, a step of producing a base material from the mixture and a step of heat-treating the base material in a reductive atmosphere. A first phase of the persistent phosphorescent ceramic composite material consists of one or more metal oxides selected from, for example, aluminum oxide, zirconium oxide, magnesium oxide, silicon oxide, titanium oxide, barium oxide, beryllium oxide, calcium oxide and chromium oxide, and the second phase consists of a metal oxide(s) containing at least one activated element of a low oxidation number and selected from, for example, aluminates of Ca, Ba, Sr and/or Mg, silicates of Ca, Ba, Sr, and/or Mg and aluminosilicates of Ca and/or Sr. Alternatively, the metal oxide in the first phase is zirconia stabilized with yttria.