Nonagglomerated, submicron α–Fe₂O₃ particles: Preparation and application

Abstract

Spherical particles of α–Fe2O3 80 to 100 nm in size were prepared with the polyol method. Scanning electron microscopy, x-ray powder diffraction, and measurements of the diffuse reflection were used to characterize the powder material. The characteristic red color of hematite was adjusted after brief heating (250 °C, 15 min) which did not lead to further particle growth. The polyol method turned out to be suited for the preparation of quite concentrated (up to 20 wt%) and very stable suspensions of submicron Fe2O3 particles. Based on such suspensions, the red emitting phosphor Y2O2S:Eu was coated as a model substrate. As a result, very homogeneous coatings of α-Fe2O3 on the phosphor material were realized. Individual iron oxide particles on the phosphor surface confirm the presence of nonagglomerated Fe2O3 particles in the polyol medium.

Inorganic Luminescent Materials: 100 Years of Research and Application

“…3). [27] Similar measures can also be taken for the green-and blue-emitting phosphors. As shown with these representative examples, by far the most industrially used phosphors have specifically modified surfaces for the one reason or another.…”

Transformation mechanism of magnetite nanoparticles

“…The increasing of particle size was probably due to irregular diffusion of particles at a higher temperature, which enhanced the growth kinetics of the particles and, consequently, larger sized particles were produced. Transformation of Fe(OH) 2 to magnetite and its conversion to maghemite and hematite under different temperatures and mediums are summarized in Table 1. The XRD results for samples b1 and e1 match well to ICDD card 240081 (maghemite) and for samples c1 and f1 correspond to ICDD card 330664 (hematite).…”

“…Iron oxides (IO), such as magnetite, maghemite and hematite nanoparticles (NP), have attracted great attention in the recent years, because of their technological and industrial applications due to their excellent and unique properties [1][2][3][4][5][6][7]. Iron oxides are metal oxides used in such fields as high density magnetic recording media, gas sensors, catalysts, pigments, nonlinear optics, anticorrosive agents, inorganic dyes, adsorbents, electronics, magnetic storage, biomedicine, ferrofluids and so on [8][9][10].…”

Synthesis of Nanocrystalline Iron Oxide Particles in the Iron(III) Acetate/Alcohol/Acetic Acid System

“…The precipitation of the corresponding salts from solution, [2e] forced hydrolysis, hydrothermal, [3a] hydrothermal in near-supercritical water, [3b] sol-gel, [3c-3f] polyol [4] and nonhydrolytic syntheses [5a-5c] are also "wet" chemistry routes often utilised in the synthesis of metal oxide particles. The sol-gel route is one of the most exploited synthetic routes, because it provides excellent control of physical, chemical and microstructural properties at the molecular level.…”