Optical properties of nanocrystalline magnesium aluminate spinel synthesized from industrial wastes

Ewais, Emad M.M.; Besisa, Dina H.A.; El‐Amir, Ahmed A. M.; El‐Sheikh, Said M.; Rayan, D. A.

doi:10.1016/j.jallcom.2015.07.116

Cited by 50 publications

(13 citation statements)

References 58 publications

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“…It was observed that all spectra showed very similar profiles, in which bands with absorption maxima around 3500 cm -1 and 1650 cm -1 were identified, attributed to the stretch vibrations of O-H groups, and of H-O-H molecules deformation of the water physically adsorbed and in interaction with MgAl 2 O 4 , respectively 3,19,28 ; an absorption band at about 2339 cm -1 , referring to the stretch vibration of C=O bond of the carbon dioxide from the air 27 ; in addition to the band with the maximum absorption, around 1370 cm -1 , attributed to the vibrations of the N-O bond of NO 3-groups. The division of the high-frequency band into two can be explained by considering that a number of Al 3+ ions occupy the sites in the spinel type structure, as indicated to Edwais et al 44 . When the FTIR spectrum of the four samples (Fig.…”

Section: Resultsmentioning

confidence: 99%

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

et al. 2017

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In this paper, magnesium aluminate spinels were prepared by microwave-assisted combustion, using urea as fuel. In order to evaluate the effect of the urea excess used in the synthesis, its mass was added in a range of 1.0 to 2.5 times the stoichiometric amount required. The materials produced were characterized by TGA, FTIR, XRF, XRD, BET, SEM and TEM. The results demonstrated that magnesium aluminate spinel was formed in all solids, but the crystallinity degree and the specific surface area increased according to the amount of urea that was used in the synthesis. The use of excess fuel in the preparation was therefore advantageous, since it eliminated the need of the calcination step, at high temperatures, in order to stabilize the spinel phase and improve the crystallinity of the solid. The heat generated in the combustion process was sufficient to develop the formation of a nanocrystalline structure and produce high purity materials, with a save of 99.4% in energy.

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Section: Resultsmentioning

confidence: 99%

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

et al. 2017

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“…Magnesium scrap and aluminum foil municipal wastes have been used for the M 2 A synthesis by co‐precipitation method 28 . The obtained gel from co‐precipitation process was washed with distilled water, dried and calcined at 1100°C in order to obtain the M 2 A powder with a MgO/Al 2 O 3 ratio of 2:1 according to the Equation ():

2 MgO + {Al}_{2} {normalO}_{3} \to MgO . {MgAl}_{2} {normalO}_{3} .

…”

Section: Methodsmentioning

confidence: 99%

Highly‐stable, nondegradable M₂A‐reinforced YSZ ceramic composites prepared by SPS

Abdelgawad

Ewais

et al. 2020

Int J Applied Ceramic Tech

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Magnesia‐rich spinel (M2A)‐reinforced yttria‐stabilized zirconia (YSZ) ceramic composites have been fabricated by SPS using m‐ZrO2, Y2O3, and waste‐derived M2A powders. The results showed that m‐ZrO2 in M2A‐free YSZ0 specimen is partially stabilized upon temperature rising into tetragonal phase whereas YSZ10‐50 composites containing 10‐50 wt% M2A demonstrated variant behavior where their m‐ZrO2 is stabilized into a cubic form. YSZ10‐50 composites SPSed at 1400°C for 30 minutes revealed greater than 99% relative density, 10‐13 GPa Vickers hardness, 3.5‐5 MPa m0.5 fracture toughness and less than 0.5% apparent porosity. Aging hydration test for five hours soaking at 134°C and water vapor pressure of 2 bar, resulted in a conversion of ~2.8% of t‐ZrO2 to m‐ZrO2 for M2A‐free YSZ0 composite but it does not affect the YSZ10‐50 composites. The outcomes indicate that M2A has significantly improved both the densification and stabilization behavior of m‐ZrO2 through facilitating the diffusion of Y3+, Mg2+, and Al3+ ions inside zirconia lattice structure. In this regard, this study opens the door wide for producing fully stabilized c‐ZrO2 ceramics that could be potentially utilized as industrial ceramics for a broad scope of structural applications of high temperature, high‐stress and corrosive environmental conditions.

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“…At first, Mg and Al scraps were utilized for preparation of MA spinel via co-precipitation method. 19,20 In a typical procedure, Al and Mg wastes were respectively dissolved in diluted aqua regia and nitric acid. Thereafter, aluminum nitrate aqueous solution was dropewisely added to a stirring aqueous solution of magnesium nitrate in order to produce MgO/Al 2 O 3 molar ratio of one-to-one.…”

Section: Raw Materials and Powder Processingmentioning

confidence: 99%

Effect of waste‐derived MA spinel on sintering and stabilization behavior of partially stabilized double phase zirconia

El‐Amir

Abdelgawad

et al. 2020

Int J Applied Ceramic Tech

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Cubic-stabilized zirconia ceramic composites have been synthesized by conventional sintering, starting from commercial m-ZrO 2 , Y 2 O 3 , and waste-derived magnesium aluminate spinel (MA) powders. In this work, the effect of sintering temperature and MA content on stabilization and densification properties of YSZ have been duly considered. MA-free YSZ0 composite sintered at 1600°C-1700°C revealed m-and t-ZrO 2 dual-phase structure where its m-ZrO 2 was partially stabilized upon temperature rising into tetragonal phase by Y 3+ diffusion inside zirconia structure. YSZ10-50 composites containing 10-50 wt% MA demonstrated dissimilar behavior where their m-ZrO 2 was transformed and stabilized into a cubic form by diffusion of Y 3+ , Mg +2 , and Al +3 inside zirconia lattice. Furthermore, densification of YSZ10-50 powder mixtures by conventional sintering at 1600°C for 2 hours resulted in fully dense compacts with micrometer-sized grains. The outcomes indicate that MA has a significant effect on m-ZrO 2 stabilization into the cubic phase structure at room temperature. In this respect, this study offers huge potentials for developing fully stabilized c-ZrO 2 ceramics that could be possibly used as industrial ceramics for structural applications of harsh chemical and thermal environmental conditions.

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Optical properties of nanocrystalline magnesium aluminate spinel synthesized from industrial wastes

Cited by 50 publications

References 58 publications

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

Highly‐stable, nondegradable M₂A‐reinforced YSZ ceramic composites prepared by SPS

Effect of waste‐derived MA spinel on sintering and stabilization behavior of partially stabilized double phase zirconia

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Optical properties of nanocrystalline magnesium aluminate spinel synthesized from industrial wastes

Cited by 50 publications

References 58 publications

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion

Highly‐stable, nondegradable M2A‐reinforced YSZ ceramic composites prepared by SPS

Effect of waste‐derived MA spinel on sintering and stabilization behavior of partially stabilized double phase zirconia

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Highly‐stable, nondegradable M₂A‐reinforced YSZ ceramic composites prepared by SPS