new colored marketed on the basis of rare earths, methods of manufacture and use

摘要

New coloured (green) inorganic pigments which are characterised in that they include mixed oxides corresponding to the formula R2MxM'yO5 in which R denotes at least one element taken from the group consisting of yttrium and the rare earths of atomic numbers between 62 and 71 inclusive, M and M' are identical or different and denote at least one element chosen from metallic elements exhibiting at least one valency state +2, and x and y are two numbers, preferably integers, whose sum is equal to 2. Process for obtaining these pigments, which consists (i) in preparing a mixture, preferably aqueous, containing soluble salts of the elements R, M and M' in the required stoichiometric proportions, (ii) in drying the mixture obtained, and then (iii) in calcining the dried product and finally, optionally, (iv) in grinding and/or disintegrating the calcined product. Finally, use of the said pigments for colouring various materials such as plastics, ceramics and others.