Phase equilibria of the La-Cu-Sn temary system at 473K

摘要

The isothermal section of the La-Cu-Sn ternary system at 473K have been investigated by means of X-ray powder diffraction(XRD)，optical microscopy(OM)，scanning electron microscopy(SEM)and differential thermal analysis(DTA)．It consists of 20 single-phase regions,43 two-phase regions and 24 three-phase regions．At 473 K，the existences of 11 binary compounds CuLa,Cu2La,Cu5La,Cu6La，Cu3Sn，Cu6Sn5，La5Sn3，La5Sn4，LaSh，La3Sn5，LaSh3 and 5 other ternary compounds CuLaSn，Cu2LaSn2，CuLa2Sn4，Cu5LaSn,Cu9LaSn4 have been confirmed．The maximum solid solubility of Cu in Cu2LaSh2 is about 7 at．％ Cu．A new ternary compound with atomic ratio close to Cu/La/Sn=1：3：4 has been found．The crystal structure of CuLa3Slh was determined and refined by means of Rietveld’s method，resulting Orthorhombic，Pd5Pu3 type，space group Cmcm．