Mechanochemical treatment of α-Fe2O3 powder in air atmosphere

Zdujić, Miodrag; Jovalekić, Čedomir; Karanović, Ljiljana; Mitrić, Miodrag; Poleti, Dejan; Skala, Dejan

doi:10.1016/s0921-5093(97)00715-6

Cited by 69 publications

(33 citation statements)

References 20 publications

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“…[5][6][7][8][9][10] Exploring and understanding the magnetic and electric modifications associated with the structural evolution in the ballmilled hematite, has been the driving force of many efforts conducted in recent years. [7][8][9][10] The crystal structure of hematite is isomorphous to alumina (␣-Al 2 O 3 ϭcorundum), with a close-packed oxygen lattice and Fe 3ϩ cations in octahedral sites.…”

Section: Introductionmentioning

confidence: 99%

Phase evolution and magnetic properties of a high-energy ball-milled hematite–alumina system

Cótica

Zanatta

Rocha

et al. 2004

Journal of Applied Physics

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The system (␣-Fe 2 O 3 ) x (␣-Al 2 O 3 ) 1Ϫx was subjected to 24 h of high-energy ball-milling varying its nominal concentration, x. The milled samples were structurally and magnetically characterized at room temperature by x-ray diffraction, Mössbauer spectroscopy, and magnetic measurements. Mössbauer studies were also performed in the temperature range 250-6 K. As a result of the earlier analyses, it was observed that the milling products were extremely dependent on the hematite starting concentration. In samples with low ␣-Fe 2 O 3 initial concentration ͑i.e., xр0.12), the paramagnetic solid solution ␣-(Fe ⌬Y Al 1Ϫ⌬Y ) 2 O 3 , the ␣-Fe and the FeAl 2 O 4 phases were identified, along with alumina, which was always residual. The presence of spinel and metallic iron was attributed to the stainless-steel vial and balls abrasion. For xϾ0.12, the iron component was no longer present but another magnetic component, corresponding to an aluminum-substituted hematite phase, ␣-(Fe 1Ϫ⌬W Al ⌬W ) 2 O 3 , could be seen to increase with increasing x. This solid solution was shown to be transitional, at room temperature, between two ordering states, weak ferromagnetic and superparamagnetic, the latter resulting from the milling induced particle size reduction. Low temperature Mössbauer spectra revealed the magnetic ordering of both solid solutions, ␣-(Fe ⌬Y Al 1Ϫ⌬Y ) 2 O 3 and ␣-(Fe 1Ϫ⌬W Al ⌬W ) 2 O 3 , and indicated the suppression of the Morin transition for the iron-rich solid solution. The magnetization versus magnetic field curves obtained for samples with xу0.12 revealed, besides a general superparamagnetic character, some hysteretic behavior due to the magnetic phases eventually existing.

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Section: Introductionmentioning

confidence: 99%

Phase evolution and magnetic properties of a high-energy ball-milled hematite–alumina system

Cótica

Zanatta

Rocha

et al. 2004

Journal of Applied Physics

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“…By performing the mechanical milling, a fraction of milling energy transfers to the powder mixture through balls to powder impacts [1,3,[11][12][13]. The transferred mechanical energy leads to an increase in crystalline defects such as dislocations, structural distortion, atom displacement as well as the formation of amorphous phase [1][2][3][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…The transferred mechanical energy leads to an increase in crystalline defects such as dislocations, structural distortion, atom displacement as well as the formation of amorphous phase [1][2][3][11][12][13]. In addition, an increase in grain boundaries takes place and highly excited surfaces form, due to the transferred energy to the mixture [1][2][3][11][12][13]. Moreover, system climbs to a higher energy level as a consequence of an increase in structural defects and disorder.…”

Section: Introductionmentioning

confidence: 99%

Effect of iron on mechanical activation and structural evolution of hematite–graphite mixture

Tahmasebi

Shamanian

Abbasi

et al. 2009

Journal of Alloys and Compounds

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“…(␣-Al 2 O 3 : corundum) and possess a hexagonal close packing lattice with the Fe 3+ cations located in the octahedral sites, presents interesting magnetic properties, and it has been extensively studied under different grinding conditions [4][5][6][7][8][9]. These studies were conducted concerning to understand and explore the electric and magnetic modifications associated with the structural evolution of the hematite submitted to milling.…”

Section: Introductionmentioning

confidence: 99%

Influence of the annealing atmosphere on the structural and microstructural properties of the mechanosynthesized (Fe2O3)0.25–(Al2O3)0.75 system

Cótica

Moreto

Szmoski

et al. 2009

Journal of Alloys and Compounds

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Mechanochemical treatment of α-Fe2O3 powder in air atmosphere

Cited by 69 publications

References 20 publications

Phase evolution and magnetic properties of a high-energy ball-milled hematite–alumina system

Phase evolution and magnetic properties of a high-energy ball-milled hematite–alumina system

Effect of iron on mechanical activation and structural evolution of hematite–graphite mixture

Influence of the annealing atmosphere on the structural and microstructural properties of the mechanosynthesized (Fe2O3)0.25–(Al2O3)0.75 system

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