Rusi2: evidence of a new binary phase in the ruthenium-silicon system

Ru2Si3 single crystals have been grown by the zone melting technique with radiation heating. These crystals contain inclusions, about 500nm in size, which consist of monocrystalline ruthenium disilicide. Endothermic peaks detected at T = 962 °C in the DTA traces of RuSix are interpreted as decomposition of RuSi2 to Ru2Si3 and Si. This enabled us to update the Si-rich part of the Ru-Si phase diagram.