Journal ArticleDOI
Crystallization of gel-derived alumina and alumina-zirconia ceramics
It Meng Low,R. McPherson +1 more
TLDR
In this article, the crystallization behavior and phase relations in gel-derived alumina and alumina-zirconia ceramics have been investigated, and the implications of microporous gel structures on the modification of microstructures in these gel-based aluminina-ceramics are discussed.Abstract:
The crystallization behaviour and phase relations in gel-derived alumina and alumina-zirconia ceramics has been investigated. Zirconia was found to form a limited metastable solid solution with the alumina matrix. When present in solid solution, zirconia phase appeared to enhance rapid growth of corundum grains. There was no apparent grain refinement in the alumina-zirconia composites. The implications of microporous gel structures on the modification of microstructures in these gel-derived ceramics are discussed.read more
Citations
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Journal ArticleDOI
Synthesis and characterization of sol–gel derived ZrO2 doped Al2O3 nanopowder
TL;DR: Al2O3-ZrO2 composite gel precursor powder containing 5-15 mol% ZrO 2 was prepared by wet chemical route in this paper, where the washed gel containing pseudoboehmite and amorphous zirconia was characterized with respect to DTA/TG, XRD and IR spectroscopy.
Journal ArticleDOI
Palladium nanoparticles supported on alumina-based oxides as heterogeneous catalysts of the Suzuki–Miyaura reaction
Andrzej Gniewek,Józef J. Ziółkowski,Anna M. Trzeciak,Mirosław Zawadzki,Hanna Grabowska,Józef Wrzyszcz +5 more
TL;DR: In this paper, the Suzuki coupling of 2-bromotoluene with phenylboronic acid, used as the test reaction, revealed that the obtained catalysts were quite efficient even at 40°C and that their catalytic activity increased at 60 and 80°C.
Journal ArticleDOI
Synthesis of Glass‐like Cordierite from Metal Alkoxides and Characterization by 27Al and 29Si MASNMR
TL;DR: A solgel process for the preparation of glass-like cordierite and ceramic oxide powder is described in this paper, where metal precursors were dissolved in 2-methoxy ethanol and the metal cations were complexed using 2,4-pentanedione to overcome different hydrolysis rates of metal alkoxides which lead to microscopic inhomogeneities during gelation.
Journal ArticleDOI
Biodiesel production using a novel heterogeneous catalyst, magnesium zirconate (Mg2Zr5O12): Process optimization through response surface methodology (RSM)
TL;DR: In this paper, a heterogeneous catalyst, magnesium zirconate (Mg2Zr5O12), was synthesized by co-precipitation and used for biodiesel production via transesterification.
Journal ArticleDOI
Thermodynamic Assessment of the ZrO2─YO1.5 System
TL;DR: In this paper, the ZrO2-AlO1.5 quasibinary system has been assessed by means of the CALPHAD (CALculation of PHAse Diagram) technique.
References
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Journal ArticleDOI
Fracture Toughness of Al2O3 with an Unstabilized ZrO2Dispersed Phase
TL;DR: The fracture toughness of Al2O3 is considerably increased by the incorporation of fine monoclinic ZrO2 particles in hot-pressed composites as mentioned in this paper, and the increase results from a high density of small matrix micro cracks absorbing energy by slow propagation.
Journal ArticleDOI
Study of phase transformations during calcination of aluminum hydroxides by selected area electron diffraction
B.C. Lippens,J.H. de Boer +1 more
TL;DR: In this paper, the formation of the well ordered super spinel structure is suppressed by obstructing the diffusion of the A1 ions either by the surface of numerous pores or by incorporating large ions such as Na ions (y-alumina from crystalline boehmite) and in these cases the disordered spinel type aluminas are transformed at a high temperature to 0and a-Al~O 3 by complete recrystallization to small particles which still have some preferred orientation.
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