ZrO2-NdO1.5 system: Investigations of phase relation and thermophysical properties. (5th May 2017)

• Record Type: Journal Article
• Authors: Nandi, Chiranjit; Jain, Dheeraj; Grover, V.; Krishnan, K.; Banerjee, Joydipta; Prakash, Amrit; Khan, K.B.; Tyagi, A.K.
• Is Part Of: Materials & design. Volume 121(2017)
• Page Start: 101
• Page End: 108
• Publication Date: 2017-05-05
• Subjects: ZrO2-NdO1.5 binary system -- Pyrochlore -- XRD -- Raman spectroscopy -- Thermal expansion -- Thermal conductivity; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2017.02.030
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Exploring the structural and thermophysical behaviour of Nd-Substituted ZrO2 is vital in context of matrices for minor actinide transmutation. Hence, phase relations have been studied in this system using high temperature sintered samples prepared by gel combustion route. Phase characterization of Zr1 − x Ndx O2 − x / 2 (0.0 ≤ x ≤ 1.0) series was carried out using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). With increasing NdO1.5 content, the system evolved in the sequence of (a) monoclinic zirconia (b) mixture of monoclinic + cubic stabilized zirconia, (c) cubic stabilized zirconia (d) mixture of stabilized zirconia + pyrochlore (e) pyrochlore (f) mixture of pyrochlore + hexagonal Nd2 O3 and (g) pure hexagonal Nd2 O3 . Lattice and bulk thermal expansion of few selected compositions were characterized by high temperature XRD (298–1273 K) and dilatometry (323–1673 K). Average coefficient of thermal expansion decreased with increasing NdO1.5 fraction in Zr1 − x Ndx O2 − x / 2 series (x = 0.2, 0.3, 0.4, 0.5) solid solutions, which has been attributed to increasing order in cation sub-lattice resulting in overall increase in lattice stability. Thermal conductivity has been reported for a representative composition Zr0.8 Nd0.2 O1.90. Graphical abstract: Highlights: Existence of multi-phasic phase field across the composition range as shown by XRD Evolution of defect fluorite to pyrochlore structure upon increasing Nd 3 + -content Ordered pyrochlore micro-domains in bulk defect fluorite lattice revealed by Raman spectroscopy. Lattice and bulk thermal expansion coefficient decreased with Nd 3 + -content as manifestation of increased ordering