Influence of nano boehmite on solid state reaction of alumina and magnesia

Zargar, H.R.; Bayati, M.R.; Rezaie, Hamid Reza; Golestani‐Fard, F.; Molaei, R.; Zanganeh, Saeid; Kajbafvala, Amir

doi:10.1016/j.jallcom.2010.07.186

Cited by 26 publications

(8 citation statements)

References 55 publications

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“…1)which indicates that stoichiometric MA spinel composed of 28.20% MgO and 71.80% Al 2 O 3 , it is illustrated that the investigated particles are spinel particles enriched with alumina. The obtained results are in a good convenience with the published data[42][43][44][45].…”

supporting

confidence: 82%

Preparation and characterization of Nano spinel powder via co-precipitation and sol-gel techniques

Khalil

Hassan

Ali

et al. 2013

Main Group Chemistry

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Different compositions of pure magnesium aluminate spinel, alumina-spinel and magnesia-spinel Nano ceramic materials were prepared using co-precipitation and sol-gel techniques. The powders prepared from different molecular compositions of the starting materials; 1 : 1, 1 : 4 and 4 : 1 of either magnesium nitrate and aluminum nitrate (co-precipitation) or magnesium chloride and aluminum hydroxide (sol-gel) were calcined at different firing temperatures; 900, 1100, 1300 and 1500 • C. The solid phase compositions of the calcined samples were investigated using x-ray diffraction analysis (XRD). The crystal size of the fired powders was calculated from XRD patterns using Scherer's equation. The microstructure and solid phase analysis of some selected samples were investigated using scanning electron microscope attached with energy dispersed x-ray unit. Based on the mineralogical, crystal size and microstructure studies, it is concluded that different compositions of pure spinel, magnesia-spinel and alumina-spinel could be attained at different firing temperatures; 900 • C, 1100 • C, 1300 • C and 1500 • C via co-precipitation and sol-gel techniques. For economical reasons firing at 900 • C is considered sufficient for obtaining pure spinel, magnesia-spinel and alumina-spinel Nano powders (<100 nm); particles prepared via sol-gel are relatively smaller compared with those prepared via co-precipitation.

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supporting

confidence: 82%

Preparation and characterization of Nano spinel powder via co-precipitation and sol-gel techniques

Khalil

Hassan

Ali

et al. 2013

Main Group Chemistry

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“…Alumina has numerous applications ranging from catalysis [5,6] to optics [7], electronics [8] and biomedicine [9,10]. Alumina and titania have been used interchangeably for many applications and each has individual drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Structural and nano-composite features of TiO2–Al2O3 powders prepared by sol–gel method

Ahmed

Abdel-Messih

2011

Journal of Alloys and Compounds

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“…It could almost accelerate diffusion and enter into vacancies caused by the absence of Mg 2+ and Al 3+ [16] . An MgAl 2 O 4 crystal nucleus was formed at grain boundaries or neighbouring lattice sites which increased the lattice constant and lattice volume [17] . Indeed, at 30 wt% and 45 wt% Al 2 O 3 /2SiO 2 additions, the lattice constant and lattice volume of MgO were unchanged: this indicated that the solid solution effect of Al 2 O 3 and MgO was limited [18] .…”

Section: Resultsmentioning

confidence: 99%

Effects of doping Al2O3/2SiO2 on the structure and properties of magnesium matrix ceramic

Zhou

Luo

et al. 2016

Materials Chemistry and Physics

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To improve the sintering properties and the thermal shock resistance of magnesium matrix ceramic, this work used micron-sized MgO as the main raw material and nano-Al 2 O 3 and SiO 2 as additives. Magnesium matrix ceramic was doped with different amounts of Al 2 O 3 and SiO 2 (Al 2 O 3 and SiO 2 at a molar ratio of 1:2) and sintered under standard atmospheric conditions. The effect of Al 2 O 3 /2SiO 2 doping amounts on sintering properties, thermal shock resistance, phase composition, and microstructure of composite ceramic materials were investivigated. The results suggested that introducing Al 2 O 3 /2SiO 2 could improve the sintering properties of magnesium matrix ceramic. The grain boundary migration of its periclase phase could be hindered by the magnesium aluminate spinel and forsterite formed by solid reaction including Al 2 O 3 , SiO 2 addition, and the MgO itself. Furthermore, according to the mechanism of thermal expansion mismatching, with increasing Al 2 O 3 /2SiO 2 addition, thermal shock times increased significantly, the number of ceramic internal micro-cracks increased after the thermal shock and the material fracture surface energy was improved. It is found that the way of transgranular combining intergranular fractures can decrease the stress concentration at the crack tips and hinder crack propagation. The secondary phase particles deflected matrix internal micro-cracks and the crack propagation path length thus increased, residual stress field were subjected to interference and energy dissipation mechanisms improved. Meanwhile, thermal shock times for the material were enhanced and the degree of densification increased with increasing sintering temperature.

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Influence of nano boehmite on solid state reaction of alumina and magnesia

Cited by 26 publications

References 55 publications

Preparation and characterization of Nano spinel powder via co-precipitation and sol-gel techniques

Preparation and characterization of Nano spinel powder via co-precipitation and sol-gel techniques

Structural and nano-composite features of TiO2–Al2O3 powders prepared by sol–gel method

Effects of doping Al2O3/2SiO2 on the structure and properties of magnesium matrix ceramic

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