On the phase existence and stability of Zr9Pd11 and Zr13Pd12 intermetallic alloys

Abstract

The intermetallic alloy Zr9Pd11 has been studied by perturbed angular correlation (PAC) spectroscopy using 181Hf probe to confirm its phase existences and to determine temperature stability of the compound. Another compound Zr13Pd12 which was reported to be present by a single group of authors and is yet to be verified by any other measurements has been studied by X-ray diffraction (XRD) to support or disprove its phase existence. Both the compounds have been synthesized by argon arc melting and for Zr9Pd11, results from atomic scale PAC measurements have been reported here for the first time. From present PAC measurement at room temperature, values of quadrupole frequency and asymmetry parameter corresponding to Zr9Pd11 have been found to be ωQ ​= ​45.6(2) Mrad/s, η ​= ​0.84(1), respectively. The variation of η with temperature has been found to be in opposite direction compared to that observed in ZrPd. From powder XRD pattern in Zr9Pd11, a predominant phase of Zr9Pd11 along with two other minor phases of Zr-Pd system (Zr3Pd4 and ZrPd3) have been observed in the sample. From XRD measurements in stoichiometric Zr13Pd12 sample, no phase of Zr13Pd12 has been observed. In this sample, the phase compositions are found to be monoclinic ZrPd (space group Cm), Zr9Pd11 (space group P4/m) and ZrPd austenite (space group Pm3¯m). Present results, therefore, do not support the previously reported phase existence of Zr13Pd12.