Flame synthesis of gamma-iron-oxide (γ-Fe2O3) nanocrystal films and carbon nanotubes on stainless-steel substrates

Hong, Hua; Memon, Nasir K.; Dong, Zhizhong; Kear, B. H.; Tse, Stephen D.

doi:10.1016/j.proci.2018.06.098

Cited by 25 publications

(26 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This peak was deconvoluted in three contributions at 708.9-709.2 eV assigned to Fe 2+ , 710.6-710.8 eV assigned to Fe 3+ , and 712.6-712.9 eV related to an interaction of Fe 2+ and Fe 3+ [42]. It is interesting to know that the Fe 2+ /(Fe 2+ + Fe 3+ ) ratios on the surface of both samples were calculated from the XPS deconvolution (see Table 6), and as expected, the Fe 2+ /(Fe 2+ + Fe 3+ ) ratio increased after etching, indicating a higher proportion of the spinel phase CoFe 2 O 4 and hematite [35,[43][44][45][46][47][48][49]. This was also supported by the higher cobalt content after etching (Table 7) from 3.24% to 8.14% in at.…”

Section: Oxide Characterizationsupporting

confidence: 60%

“…The formation of hematite is related to the atmospheres used in the heat treatment in this research. Hong et al [44] and Zhang et al [66] described that iron-based materials oxidized at temperatures between 377 • C and 527 • C under steam, and mainly with CO 2 atmospheres, producing negative free energy for the formation of hematite; therefore, under these conditions, part of the magnetite exposed to higher concentrations of oxygen (outermost layers) is oxidized to hematite (Fe 3 O 4 → α-Fe 2 O 3 ) [56,62,66]. Genuzio et al [62] also mentioned that the kinetics of this transformation are very fast and that it depends on the chemical composition and the availability of defects in the crystalline network, which allow for the growth of the new phase through specific crystallographic plans.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization Study of an Oxide Film Layer Produced under CO2/Steam Atmospheres on Two Different Maraging Steel Grades

Florez

Fargas

Rovira

et al. 2021

Metals

View full text Add to dashboard Cite

Currently, surface treatments lead to inducing a superficial layer of several nanometers up to micrometer, which in some cases can be protective. In this experimental work, an oxide layer was generated under different atmospheres (CO2 and steam atmospheres) during the thermal aging treatment of two different maraging grades, 300 and 350. Afterwards, this layer was microstructural and mechanically characterized by advanced characterization techniques at the micro- and submicron length scale to highlight some information related to the generated oxide layer. The results showed that the oxide layer (in both grades) was made up of several compounds like: TiO2, MoO3, hematite (α-Fe2O3), and CoFe2O4, this being the majority compound distributed homogeneously throughout the layer. Furthermore, a nickel-rich austenitic phase at the interphase was mainly made up cobalt ions (Co2+), instead of iron ions (Fe2+), within the spinel lattice.

show abstract

Section: Oxide Characterizationsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Characterization Study of an Oxide Film Layer Produced under CO2/Steam Atmospheres on Two Different Maraging Steel Grades

Florez

Fargas

Rovira

et al. 2021

Metals

View full text Add to dashboard Cite

show abstract

“…So far, the continuous large-scale synthesis of ultra-small UCNPs is still a challenge to be solved. It is worth noting that gas-phase synthesis technology (e.g., flame aerosol synthesis) has become a potential approach due to its rapid manufacture, high-throughput production and continuous synthesis capabilities [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Recently Ju et al successfully synthesized Yb 3+ /Er 3+ co-doped UCNPs through flame spray synthesis method [ 36 ].…”

Section: Introductionmentioning

confidence: 99%

Dual-Wavelength Excited Intense Red Upconversion Luminescence from Er3+-Sensitized Y2O3 Nanocrystals Fabricated by Spray Flame Synthesis

Zhao

Yang

et al. 2020

Nanomaterials

View full text Add to dashboard Cite

Er3+-sensitized upconversion nanoparticles (UCNPs) have attracted great attention due to their tunable upconversion (UC) emissions, low cytotoxicity, high resistance to photobleaching and especially multiple effective excitation wavelengths. However, detailed energy conversion between Er3+ and Tm3+ ions in Y2O3 UCNPs is still a problem, especially under multi-wavelength and variable pulse width excitation. In this work, we successfully fabricated a series of Er3+-sensitized Y2O3 nanocrystals by a spray flame synthesis method with a production rate of 40.5 g h−1. The as-prepared UCNPs are a pure cubic phase with a mean size of 14 nm. Excited by both 980 and 808 nm lasers, the tunable upconversion luminescence (UCL) from Er3+ ions was achieved by increasing the Er3+ doping concentration, co-doping Tm3+ ions and extending excitation pulse-width. The investigations of the lifetimes and the laser power dependence of UC emissions further support the proposed mechanism, which provides guidance for achieving effective color control in anticounterfeiting and multiplexed labeling applications. In addition, the red UC emission at about 5 mm beneath the tissue surface was observed in an ex vivo imaging experiment under the excitation of 808 nm laser, indicating that the Y2O3:Er3+/Tm3+ UCNPs have great prospects in further biological applications.

show abstract

“…Furthermore, hematite phase is formed due to the atmospheres used during aging process. Zhang et al [41] and Hong et al [42] described that during oxidation between 375 and 526 • C in atmospheres containing water vapor, the outermost layers are exposed to a higher concentration of oxygen, and part of the magnetite oxidizes to hematite (Fe 3 O 4 → α-Fe 2 O 3 ) [40][41][42][43].…”

Section: Eds Quantitative Analysis From Pointsmentioning

confidence: 99%

Oxidation Behavior of Maraging 300 Alloy Exposed to Nitrogen/Water Vapor Atmosphere at 500 °C

Florez

Fargas

Cardoso

et al. 2021

Metals

View full text Add to dashboard Cite

Aging heat treatments in maraging steels are fundamental to achieve the excellent mechanical properties required in several industries, i.e., nuclear, automotive, etc. In this research, samples of maraging 300 alloy were aged using a novel procedure that combines different steps with two atmospheres (nitrogen and water vapor) for several hours. The oxidized surface layer was chemical, microstructural and micromechanically characterized. Due to the thermodynamic and kinetic conditions, these gases reacted and change the surface chemistry of this steel producing a thin iron-based oxide layer of a homogeneous thickness of around 500 nm. Within the aforementioned information, porosity and other microstructural defects showed a non-homogeneous oxide, mainly constituted by magnetite, nickel ferrite, cobalt ferrite, and a small amount of hematite in the more external parts of the oxide layer. In this sense, from a chemical point of view, the heat treatment under specific atmosphere allows to induce a thin magnetic layer in a mixture of iron, nickel, and cobalt spinel ferrites. On the other hand, the oxide layer presents an adhesive force 99 mN value that shows the capability for being used for tribological applications under sliding contact tests.

show abstract

Flame synthesis of gamma-iron-oxide (γ-Fe2O3) nanocrystal films and carbon nanotubes on stainless-steel substrates

Cited by 25 publications

References 46 publications

Characterization Study of an Oxide Film Layer Produced under CO2/Steam Atmospheres on Two Different Maraging Steel Grades

Characterization Study of an Oxide Film Layer Produced under CO2/Steam Atmospheres on Two Different Maraging Steel Grades

Dual-Wavelength Excited Intense Red Upconversion Luminescence from Er3+-Sensitized Y2O3 Nanocrystals Fabricated by Spray Flame Synthesis

Oxidation Behavior of Maraging 300 Alloy Exposed to Nitrogen/Water Vapor Atmosphere at 500 °C

Contact Info

Product

Resources

About