Effect of Yb2O3 doping on the grain boundary of NiFe2O4-10NiO-based cermets after sintering

• Published in: International journal of minerals, metallurgy and materials Vol. 22; no. 12; pp. 1334 - 1341
• Main Author: He, Han-bing
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01.12.2015; Springer Nature B.V; School of Metal urgy and Environment, Central South University, Changsha 410083, China
• Subjects: Aluminum; Ceramics; Cermets; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion and Coatings; Corrosion resistance; Decomposition reactions; Doping; Electrical resistivity; Electrolysis; Electron probe microanalysis; Fe2O3; Glass; Grain boundaries; Materials Science; Metallic Materials; Microstructural analysis; Natural Materials; Nickel ferrites; Phase composition; Sintering; Specific gravity; Surfaces and Interfaces; Thin Films; Tribology; X-ray diffraction; X-ray spectroscopy; X射线光谱仪; Yb2O3; 扫描电子显微镜; 掺杂; 晶界; 金属陶瓷; 陶瓷烧结; doping; aluminum electrolysis; grain boundaries; cermets; ytterbium oxide
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-015-1202-z

xYb2O3-15（20Ni-Cu）/（85 -x）（NiFe2O4-10NiO） （x = 0, 0.25, 0.5, 0.75, 1.0, 2.0, and 10.0） cermets for aluminum electrolysis were prepared to investigate the effect ofYb2O3 doping on the grain boundary of the cermets after sintering. The results showed that each interface was very clear and that with increasing Yb2O3 content, most of the Yb was evenly distributed at the grain boundary. Moreover, according to the phase composition and microstructural analysis by X-ray diffraction （XRD）, scanning electron microscopy with energy dispersive X-ray spectroscopy （SEM/EDX）, and electron probe microanalysis （EPMA）, YbFeO3 was produced along the grain boundary. The YbFeO3 was concluded to not only have formed from the interaction between the NiFe2O4 or Fe2O3 component and Yb2O3 at the grain boundary of the cermets, but also from the decomposition of NiFe2O4 into NiO and Fe2O3 and the subsequent reaction of Fe2O3 with Yb2O3. Thus, the production of YbFeO3 resulted in a cermet with high relative density, good electrical conductivity, and good corrosion resistance.