000119742 001__ 119742
000119742 005__ 20240319081025.0
000119742 0247_ $$2doi$$a10.1016/j.jallcom.2022.166449
000119742 0248_ $$2sideral$$a130522
000119742 037__ $$aART-2022-130522
000119742 041__ $$aeng
000119742 100__ $$aGrima, L.
000119742 245__ $$aPyrochlore-like ZrO2-PrOx compounds: The role of the processing atmosphere in the stoichiometry, microstructure and oxidation state
000119742 260__ $$c2022
000119742 5060_ $$aAccess copy available to the general public$$fUnrestricted
000119742 5203_ $$aThe object of this work is to study the relation between composition, microstructure and oxidation state of Pr2±xZr2∓xO7±y materials produced by the laser–floating zone (LFZ) technique. Three compositions are studied, nominally Pr1.7Zr2.3O7+y, Pr2Zr2O7+y and Pr2.24Zr1.76O7±y, all within the pyrochlore field in the ZrO2–PrOx phase diagram. Samples have been processed under four different atmospheres (O2, air, N2 and 5%H2(Ar)), so as to vary the environmental conditions from oxidising to reducing. Sample colouration ranged from dark brown to bright green, owing to varying Pr4+ content. A close correlation is found between the phase homogeneity, the microstructure and the Pr content. Pr–deficient samples present a homogeneous microstructural aspect and composition, whereas Pr–rich compositions always break into 5–25 µm–sized grains with pyrochlore phases at the grain centre and ill–crystallised, Pr–rich oxidised phases at the grain–boundaries. Raman spectroscopy shows that different types of oxygen disorder occur depending on composition and processing atmosphere: in Pr–poor samples oxygen interstitials are created to compensate for Zr4+ excess charge, whereas in Pr–rich samples oxygen disorder occurs around the Pr3+ or Pr4+ ions substituting for Zr4+, because of size–mismatch. Magnetic measurements showed a high Pr4+ content, which has been attributed to several factors: the highly oxidised state of the feedstock material, the segregation of Pr and O–rich grain boundaries in compositions with praseodymium molar rate> 0.5, and the lower oxide–ion conductivity for PZO compositions, compared to either Pr–poor or Pr–rich compositions. Post–processing thermal annealing in a vacuum at 1000 °C enabled total Pr reduction, with the exception of the Pr–rich P2.24 samples, where some Pr4+ ions remained in the oxidised state.
000119742 536__ $$9info:eu-repo/grantAgreement/ES/AEI/PID2019-107106RB-C32$$9info:eu-repo/grantAgreement/ES/MINECO/BES-2017-079683$$9info:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2016-77769R
000119742 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc-nd$$uhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/
000119742 590__ $$a6.2$$b2022
000119742 592__ $$a1.079$$b2022
000119742 591__ $$aMETALLURGY & METALLURGICAL ENGINEERING$$b8 / 79 = 0.101$$c2022$$dQ1$$eT1
000119742 593__ $$aMaterials Chemistry$$c2022$$dQ1
000119742 591__ $$aCHEMISTRY, PHYSICAL$$b45 / 161 = 0.28$$c2022$$dQ2$$eT1
000119742 593__ $$aMetals and Alloys$$c2022$$dQ1
000119742 591__ $$aMATERIALS SCIENCE, MULTIDISCIPLINARY$$b91 / 343 = 0.265$$c2022$$dQ2$$eT1
000119742 593__ $$aMechanics of Materials$$c2022$$dQ1
000119742 593__ $$aMechanical Engineering$$c2022$$dQ1
000119742 594__ $$a10.9$$b2022
000119742 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000119742 700__ $$0(orcid)0000-0003-2242-6822$$aPeña, J.I.$$uUniversidad de Zaragoza
000119742 700__ $$0(orcid)0000-0002-5793-2058$$aSanjuán, M.L.
000119742 7102_ $$15001$$2065$$aUniversidad de Zaragoza$$bDpto. Ciencia Tecnol.Mater.Fl.$$cÁrea Cienc.Mater. Ingen.Metal.
000119742 773__ $$g923 (2022), 166449 [11 pp.]$$pJ. alloys compd.$$tJOURNAL OF ALLOYS AND COMPOUNDS$$x0925-8388
000119742 8564_ $$s3782977$$uhttps://zaguan.unizar.es/record/119742/files/texto_completo.pdf$$yVersión publicada
000119742 8564_ $$s2889503$$uhttps://zaguan.unizar.es/record/119742/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000119742 909CO $$ooai:zaguan.unizar.es:119742$$particulos$$pdriver
000119742 951__ $$a2024-03-18-16:36:51
000119742 980__ $$aARTICLE