The 500K Isothermal Sections Of The Phase Diagram Of The Ni-Pb-Sb Ternary System And Rietveld Refinement For A New Compound Al₂SbY₅

1. The 500K isothermal section of the phase diagram of the Ni-Pb-Sb ternary system is investigated by powder X-ray diffraction (XRD), differential thermal analysis (DTA), and optical microscopy techniques.The 500K isothermal section consists of 7 single-phase regions, 11 two-phase regions and 5 three-phase regions. The 7 single-phase regions are: (Ni), (Pb), (Sb), (NiSb2), (NiSb), (Ni5Sb2), (Ni3Sb) . The 11 two-phase regions are: . The 5 three-phase regions are: At 500K, the maximum solid solubility of Sb in Ni is about 6.25at.%Sb, The solid solubility of Sb in NiSb is from 49.0at%Sb to 52.3at.%Sb, the maximum solid solubility of Sb in Pb is about 3.9at.%Sb;.It is proved that the compound in Ni-Sb system is Ni5Sb2, not Ni7Sb3 at 500K. The existence of any ternary compounds has not been observed in the 500K isothermal sections.2. The crystal structure of a new compound Al2SbY5 has been determined from X-ray powder diffraction data using Rietveld method. The new compound has a hexagonal structure with the lattice parameters a=8.8312(3) , c=6.4795(2) A, Z=2 and space group of P63/mcm(193).The calculated density is 4.705g/cm3.