Synthesis and characterization of 50-50 wt. lanthanum aluminate-lanthanum zirconate composite dried by spray-drying
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MRS Advances © 2020 Materials Research Society DOI: 10.1557/adv.2020.270
Synthesis and characterization of 50-50 wt. Lanthanum aluminate-lanthanum zirconate composite dried by spray-drying W. Hernández Muñoz1, J. Zárate Medina2, J. Serrato Rodríguez2, J. Muñoz Saldaña3 1
Universidad ECCI, Carrera. 19 No. 49-20, Bogotá, Colombia, Código Postal 111311
2
Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, México
3
Cinvestav Unidad-Queretaro, Queretaro, Libramiento Norponiente No. 2000, Fracc Real de Juriquilla Querétaro, CP.76230 Querétaro México
ABSTRACT
Lanthanum aluminate-lanthanum zirconate composite was synthesized by using coprecipitation and powders were dried by spray-drying. Pseudoboehmite was used as a precursor of lanthanum aluminate during the precipitation process. Highly crystalline phases were obtained. Lanthanum zirconate exhibits a pyrochlore structure at lower synthesis temperature (>1500°C). Due drying technique lanthanum aluminate particles appear surrounded by lanthanum zirconate. No other remaining phases were observed and the phase distribution in the composite was homogeneous.
INTRODUCTION Lanthanum zirconate (LZO) crystallize in pyrochlore structure has been subject of a lot research due its thermal, electric and electronic properties [1]–[4] and different processing routes including combustion, solid state reaction and sol-gel have been proposed [5]–[7]. However, practical applications of LZO are limited due its low 1
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fracture toughness [6], [10]. In order to overcome this issue a reinforcement phase was added [8] [9][3], the main toughening mechanism consist in ferroelastic switching induced in the reinforcement phase. Lanthanum aluminate (LAO), this rare earth aluminate has electronic, electrical and thermal properties [10] [11] [12] and exhibits ferroelastic switching [13] [14] which makes it a suitable reinforcement phase for LZO. Common processes to obtain LAO included solid state reaction of La2O3 and Al2O3, combustion synthesis of nitrates of lanthanum and aluminate, one of the major drawbacks of these techniques is the use of reactive grade precursors and high synthesis temperatures. In a previous work we proved that LAO can been produced by reverse precipitation using pseudobehmite (PB) as starting precursor and spray-drying as drying technique [15], the results indicate that LAO crystallized in perovskite structure which according to literature presents ferroelastic switching. PB is a poor crystallized aluminium oxyhydroxide; its synthesis requires lowcost materials [15]. In this work we report the results regarding synthesis and characterization of a 50-50 wt. LZO-LAO composite synthetized by precipitation method using PB particles as LAO precursor. The main goal of the present
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