Eu3+-Nd2O3 blue pigmented solid solutions

Usually, Nd2O3 shows a polymorphism based on the hexogonal Ln(2)O(3) A type and cubic Ln(2)O(3) C type structures, which have coordination numbers of 7 and 6 respectively. The Nd3+ (4f(2)) ion in an octahedral environment produces a reddish shade. In the present study, EuxNd2-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 XRD, UV-V-NIR spectroscopy, and SEM-EDX techniques.