Cerium phosphate and / or terbium phosphate, optionally with lanthanum, phosphor resulting from said phosphate, and process for producing said phosphor

摘要

The present invention relates to rare earth element phosphates (Ln). Ln is at least one rare earth element selected from cerium and terbium, or lanthanum in combination with at least one of the above two rare earth elements. The rare earth element phosphate (Ln) has a rhabdophene type with a maximum sodium content of 6000 ppm or a monazite mixed type crystal structure with a maximum sodium content of 4000 ppm. Phosphate is obtained by precipitating rare earth chlorides at a constant pH of less than 2 and then calcining and redispersing in warm water. The invention also relates to a phosphor obtained by calcination of the phosphate at at least 1000 ° C.