Eu 3+ -Nd 2 O 3 blue pigmented solid solutions

Usually, Nd₂O₃ shows a polymorphism based on the hexagonal Ln₂O₃ A type and cubic Ln₂O₃ C type structures, which have coordination numbers of 7 and 6 respectively. The Nd³⁺ (4f²) ion in an octahedral environment produces a reddish shade. In the present study, Eu_xNd_2-xO₃ compositions were prepared by ceramic and coprecipitation (from chloride solution) methods using several flux agents. Using the ceramic route, Nd₂O₃ C type structure was detected and the samples were colourless, but using coprecipitation, NdOCl crystallised from an amorphous coprecipitate at low temperature, developing the unusual monoclinic EuNd₂O₃ B type doped polymorph which is blue in colour. When enamelled using a conventional industrial tile glaze, these blue coprecipitated samples gave L*a*b* = 75/1/-11 in the CIE colour convention. Samples were characterised by X RD, U V-V-NIR spectroscopy, and SEM-EDX techniques.