Gas-phase flame synthesis and properties of magnetic iron oxide nanoparticles with reduced oxidation state

Abstract

Iron oxide nanoparticles of reduced oxidation state, mainly in the form of magnetite, have been synthesized utilizing a new continuous, gas-phase, nonpremixed flame method using hydrocarbon fuels. This method takes advantage of the characteristics of the inverse flame, which is produced by injection of oxidizer into a surrounding flow of fuel. Unlike traditional flame methods, this configuration allows for the iron particle formation to be maintained in a more reducing environment. The effects of flame temperature, oxygen-enrichment and fuel dilution (i.e. the stoichiometric mixture fraction), and fuel composition on particle size, Fe oxidation state, and magnetic properties are evaluated and discussed. The crystallite size, Fe(II) fraction, and saturation magnetization were all found to increase with flame temperature. Flames of methane and ethylene were used, and the use of ethylene resulted in particles containing metallic Fe(0), in addition to magnetite, while no Fe (0) was present in samples synthesized using methane.

Physicochemical Properties of the Solid Component of Welding Aerosol. I. Phase Composition

“…[12]. Оксиды железа присут-�-16 указывается в работе [12]. Оксиды железа присут--16 указывается в работе [12].…”

“…Оксиды железа присут-�-16 указывается в работе [12]. Оксиды железа присут--16 указывается в работе [12]. Оксиды железа присут-ствуют в виде гетита Таким образом, совершенно очевидно существенное отличие фазового состава ТССА, полученных при сварке металлов электродами АНО-4 и ЦЛ-11.…”

“…Вопрос применения твердой составляющей сварочного аэрозоля в качестве катализатора низкотемпературного разложения озона впервые освещен в работе [7]. Из анализа литературных данных [8][9][10][11][12][13] следует, что химический и фазовый состав ТССА зависит от режима сварки, природы свариваемого металла и электродов. Последние, как правило, отличаются химическим составом проволоки и покрытия.…”

Orta frekans indüksiyon yöntemi ile nano-metal ve nano-metal oksit partikül sentezinin incelenmesi

“…Moreover, these nanoparticles offer many potential applications namely, catalytic materials, waste water treatment adsorbents, pigments, gas sensors, ion exchangers, coatings, magnetic data storage devices [28][29][30][31]. Table 3 summarizes the former papers on the control size of iron oxide particles by adjusting the precursor types and precursor concentration in different spray pyrolysis process, respectively [32][33][34][35][36]. As seen different types of iron compounds such as Fe(CO)5, Fe(NO3)3, FeSO4, FeCl3 are suitable for the production of iron oxide particles in the spray pyrolysis method.…”

Microwave Plasma Synthesis of Materials—From Physics and Chemistry to Nanoparticles: A Materials Scientist’s Viewpoint

“…Since the end of the late 1980s, several gas phase synthesis methods are used for the synthesis of materials, especially matter in form of powders and nanoparticles [1][2][3][4][5][6][7][8][9][10][11][12]. The common feature of all gas phase methods is that they use vaporized chemical compounds or precursors, which undergo a chemical reaction in a gaseous environment.…”