ИСТИНА

The solid-state equalibria in the ternary system Ce-Ru-Al at 550 ˚C were established by means powder X-ray diffraction and energy-dispersive X-ray (EDX) spectroscopy on about 120 alloys which were synthesized by arc-melting under argon atmosphere. At 550 ˚C eleven ternary intermetallics were observed (Fig.). Their crystallographic parameters will be presented in further publication. Two novel intermetallics – Ce2Ru2Al and Ce2RuAl – belong to the new own structure types. Its atomic orders were determined by single crystal X-ray technique and confirmed by powder X-ray diffraction. The crystal structure of Ce44Ru33Al23 (at. %) is still unknown. The ternary compounds CeRu3Al10 and Ce11Ru2Al6 reported before were not detected at 550 ˚C in our work.