Please use this identifier to cite or link to this item: http://cimav.repositorioinstitucional.mx/jspui/handle/1004/2365
Magnetism and decarburization-like diffusion process on V2O5-doped ZnO Ceramics
SION FEDERICO OLIVE MENDEZ
CARLOS ROBERTO SANTILLAN RODRIGUEZ
KARLA CAMPOS VENEGAS
José Andrés Matutes Aquino
FRANCISCO ESPINOSA MAGAÑA
Acceso Abierto
Sin Derechos Reservados
Magnetism, Decarburization, Diffusion, V2O5, ZnO, Ceramics
We report on vanadium-doped ZnO ceramics to be used as sputtering targets. Prior to a sintering process, ZnO and V2O5 powders were milled in stoichiometric proportion to obtain Zn0.95V0.05O1 þδ composition. Sintering process of compressed powders was carried out at 900, 1000 and 1100 °C in air for 1, 2, 4, 6, 10 and 14 h. During the sintering process, decarburization-like diffusion of V2O5 (i.e. reduction of the V concentration in the pellet) leads to a non-homogeneous distribution of V. The solution of second Fick's law for a decarburization process C(z,t)=(C0 - CS)erf (z/2√(δDgbt ))+Cs was used to find δDgb, where Dgb is the grain boundary diffusion coefficient and δ the grain boundary width. δDgb strongly depends on sintering time, given that ZnO grain growth is accomplished with a simultaneous reduction of high diffusivity paths. X-ray diffraction analysis shows that residual V2O5 react with ZnO to produce γ-Zn3(VO4)2 and ZnV2O4 secondary phases that nucleate during cooling in interstitial sites between ZnO grains. Energy Dispersive X-Ray Spectroscopy (EDS) analysis was used to obtain vanadium concentration profiles. No vanadium was observed in the lattice of ZnO grains, the only diffusion mechanism corresponds to Harrison's C-type kinetics. Ceramics exhibit a very low magnetization, reaching a maximum saturation magnetization Ms=14.6*10-3 emu/cm3 on the sample annealed at 1100 °C for 1 h. Magnetic signals are originated at the interface between the V-based secondary phases and ZnO grains, where a composition near to Zn0.95V0.05O is obtained.
Centro de Investigación en Materiales Avanzados.
02-02-2015
Artículo
Inglés
PROCESOS QUÍMICOS
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