Synthesis of zirconium tungstate-zirconia core-shell composite particles

Journal Article · Tue Nov 15 04:00:00 EST 2011 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2011.07.006· OSTI ID:22210125

Khazeni, Nasser ^[1]; Mavis, Bora ^[2]; Guenduez, Guengoer ^[1]; Colak, Uner ^[3]

---

1. Chemical Engineering Department, Middle East Technical University, Ankara 06531 (Turkey)
2. Mechanical Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)
3. Nuclear Engineering Department, Hacettepe University, Beytepe Ankara 06800 (Turkey)

Highlights: {yields} ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell particles to offer solutions for sintering problems. {yields} Core synthesis by a precursor based on tungstic acid and zirconium acetate. {yields} Shell phase by urea hydrolysis in the presence of zirconium ions. {yields} [Urea]/[ZrOCl{sub 2}] ratio controls the rate of shell precursor precipitation. -- Abstract: In this work, ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell composite particles were synthesized. ZrW{sub 2}O{sub 8} that was used in the core is a material with negative coefficient of thermal expansion, and it was synthesized from a high-pH precursor based on use of tungstic acid and zirconium acetate. Shell layer was composed of ZrO{sub 2} nanocrystallites and precipitated from an aqueous solution by urea hydrolysis. While volume of the shell was effectively controlled by the initial zirconium ion concentration in the solutions, the rate of precipitation was a function of the ratio of initial concentrations of urea to zirconium ions. It is hypothesized that isolation of the ZrW{sub 2}O{sub 8} within a layer of ZrO{sub 2}, will be a key element in solving problems associated with reactivity of ZrW{sub 2}O{sub 8} towards other components in sintering of ceramic-ceramic composites with tuned or zero thermal expansion coefficient.

• OSTI ID: 22210125
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 11 Vol. 46; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AQUEOUS SOLUTIONS
CERAMICS
CONTROL
HYDROLYSIS
LAYERS
PRECIPITATION
SYNTHESIS
THERMAL EXPANSION
X-RAY DIFFRACTION
ZIRCONIUM
ZIRCONIUM IONS
ZIRCONIUM OXIDES
ZIRCONIUM TUNGSTATES