Sol-gel synthesis of Mn1.5Co1.5O4 spinel nano powders for coating applications

Journal Article · Fri Jun 15 00:00:00 EDT 2018 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2018.02.040· OSTI ID:22805134

Dayaghi, Amir Masoud ^[1]; Askari, M. ^[2]; Gannon, Paul E. ^[3]

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1. Fuel Cell Research Center/Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673 (Korea, Republic of)
2. Department of Material Science & Engineering, Sharif University of Technology, Tehran, 11155-9466 (Iran, Islamic Republic of)
3. Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717 (United States)

Highlights: • Nano powder of Mn/Co spinel, applicable to solid oxide fuel cell, is synthesized. • The sol-gel synthesis of nanocrystalline Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel is investigated. • Sol-gel annealing temperature, time, and metal-to-citrate ratio are evaluated. • The optimum conditions for producing dual phase of Mn{sub 1.5}Co{sub 1.5}O{sub 4} are achieved. - Abstract: Mn{sub 1.5}Co{sub 1.5}O{sub 4} oxide spinels are widely used as protective coatings for stainless steel interconnects within planar solid oxide fuel cell stacks. Containing both cubic and tetragonal crystalline phases, these Mn/Co oxide spinels exhibit favorable thermal stability and electronic conductivity for the SOFC interconnect application. Slurry-based coating applications of Mn/Co oxides require precursor powders, which can benefit from being nano-structured. In this study, the sol-gel synthesis of nanocrystalline Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel is investigated. The decomposition of sol-gel precursors, as well as the crystalline phase structures and microstructures of the product Mn{sub 1.5}Co{sub 1.5}O{sub 4} are characterized by differential thermal and thermogravimetric (DTA/TG) analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The effects of various sol-gel annealing temperatures (T), treatment times (t), and citrate-to-metal ratios (Rc) are evaluated. Results suggest that nanocrystalline Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel can be synthesized around 1050 °C, and that T = 1050 °C, t = 6 h and Rc = 2 are optimum conditions for producing the smallest grain size. Image analysis of TEM results shows that the size of Mn{sub 1.5}Co{sub 1.5}O{sub 4} crystallites increases with increasing temperature, with average particle sizes ranging from ∼70 nm to ∼1 μm. Selected area diffraction pattern (SADP) of Mn{sub 1.5}Co{sub 1.5}O{sub 4} spinel synthesized at 800 °C confirms the dual (cubic/tetragonal) structure of Mn{sub 1.5}Co{sub 1.5}O{sub 4}.

• OSTI ID: 22805134
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Vol. 102; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ANNEALING
CITRATES
COBALT OXIDES
CRYSTALS
DIFFERENTIAL THERMAL ANALYSIS
GRAIN SIZE
IMAGE PROCESSING
MANGANESE OXIDES
NANOSTRUCTURES
PARTICLE SIZE
POWDERS
PROTECTIVE COATINGS
SOL-GEL PROCESS
SOLID OXIDE FUEL CELLS
SPINELS
STAINLESS STEELS
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION