Iranian Journal of Materials Science and Engineering

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Abstract:

composition of MgO and nano boehmite. The reactant and potassium chloride, as the reaction media, were fired at

800-1000 °C at different dwell times (0.5-5 h) in the ambient atmosphere. After washing and filtration, the spinel nano

powder was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Brunauer-Emmett-

Teller (BET) techniques. It was demonstrated that the formation temperature decreased to 850

particles revealed an average size of 30 nm with a narrow size distribution. The mechanism of MgAl

was found to be a template type where the morphology and size of product were similar to those of alumina formed

from boehmite decomposition. Prolonging the reaction time from 0.5 to 3 h, the reaction was further completed and

crystallinity was improved. However, the increase of temperature was more effective in this regard.

MgAl2O4 (MA) nano powder was synthesized via molten salt technique, by heating stochiometric°C. The nano spinel2O4 formation

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Ultraviolet–Visible (UV–Vis) spectroscopy was used, in the current investigation, to explore the dispersion and stability of titania nanoparticles in an aqueous media with different types of dispersants. Hydrochloric and nitric acids as well as ammonia were used to determine the stability of the suspension in the acidic region (pH=2.5) and basic area (pH=9.5), respectively. In addition, for measuring sustainability of suspension and creating steric, and electrosteric repulsive forces, ethylene glycol and ethylene glycol plus ammonia were employed, respectively. UV–V is
spectrometry was applied to realize the effect of nano titania concentrations and different types of dispersants of samples containing different amounts of nano titania and different types of dispersants on stability of TiO2-containing suspensions. In addition, the stability of dispersion could be evaluated in colloidal mixtures containing ethylene glycol plus ammonia. It was demonstrated that the mixtures containing ethylene glycol plus ammonia were stable over a period of 4 days. To support the UV–Vis results, other techniques such as atomic force microscopy (AFM) and scanning electron microscopy (SEM) were employed to study the degree of agglomeration of titania nanoparticles in terms ofmorphology and size.