Nucleation and growth processes of α-Fe nanocrystals in amorphous NdFeBCoDy: <i>In situ</i> x-ray diffraction studies

Li, W.; Li, X.H.; Sun, Hongyu; Zhang, J.W.; Zhang, X.Y.

doi:10.1063/1.1871338

Cited by 11 publications

(7 citation statements)

References 16 publications

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“…8c,d , we can further confirm that the dark areas are due to the existence of the crystal structure. According to the basal plane distance of the crystal structure and EDS of the worn particles, these crystals are identified as Fe nanocrystals 44 45 . Results suggest that the sandwich sheets were formed through the Fe nanocrystals absorbed on the graphene basal plane and interlayer during friction process which can further enhance the load–carrying ability and improve the friction reducing and antiwear abilities.…”

Section: Resultsmentioning

confidence: 99%

Graphene with outstanding anti-irradiation capacity as multialkylated cyclopentanes additive toward space application

Fan

Wang

2015

Sci Rep

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Multialkylated cyclopentanes (MACs), a class of synthetic hydrocarbon fluid have attracted intensive interest as possible space lubricants due to a series of unique physical and chemical properties. Here, we used graphene with high mechanical strength and chemical inertness as lubricant additive to explore its potential for space application. The effects of space irradiation on graphene and the tribological properties of graphene as lubricant additive were firstly investigated in detail under simulated space environment composed of high vacuum, high/low temperature and irradiation. Results demonstrate that graphene not only possesses outstanding anti–irradiation capacity but also significantly improves the space performance and tribological properties of MACs, which depends on the excellent physicochemical properties and high load-carrying ability of graphene as well as more effective separation of the sliding surfaces.

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Section: Resultsmentioning

confidence: 99%

Graphene with outstanding anti-irradiation capacity as multialkylated cyclopentanes additive toward space application

Fan

Wang

2015

Sci Rep

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“…When studying devitrification of metallic glasses authors of many works tend to use a simple approach and refine only the narrow part of the XRD profile, mostly in the vicinity of the first sharp diffraction peak. 28,29 Then the intensity profile is fitted with two peak functions, one representing an amorphous component and a second one corresponding to a Bragg peak. Lorentz, Gaussian or Pseudo-Voigt functions are usually used to describe intensity profiles.…”

Section: Resultsmentioning

confidence: 99%

“…It is seen that the relative fraction of the crystalline component calculated from the XRD profile strongly depends on the 2θ interval used. When studying devitrification of metallic glasses authors of many works tend to use a simple approach and refine only narrow part of the XRD profile, mostly in the vicinity of the first sharp diffraction peak 28,29 . Then the intensity profile is fitted with two peak functions, one representing an amorphous component and a second one corresponding to a Bragg peak.…”

Section: Crystallization Kineticsmentioning

confidence: 99%

In situ XRD studies of nanocrystallization of Fe-based metallic glass: a comparative study by reciprocal and direct space methods

Bednarčı́k

Michalik

Kolesár

et al. 2013

Phys. Chem. Chem. Phys.

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Structural changes occurring in an Fe(72.5)Cu1Nb2Mo2Si(15.5)B7 alloy during a combination of constant rate heating (20 K min(-1)) and isothermal holding at 500 and 520 °C were investigated using in situ high-energy X-ray diffraction. We found that the ferromagnetic-to-paramagnetic transition of the amorphous phase is revealed as a change in the slope of the thermal expansion curve when heating a sample at a constant rate up to 520 °C. Real space analysis by means of the atomic pair distribution function (PDF) demonstrated that the rate and extent of the thermal expansion strongly depend on the interatomic separation. The PDF proved to be a reliable method for the description of crystallization kinetics. Further it allows determination of sizes of ultrafine nanocrystals with grain sizes well below 8 nm and thus makes observation of early stages of nanocrystallization possible. Following grain growth kinetics during isothermal annealing at 500 and 520 °C we found that the activation energy of the process is 357 ± 12 kJ mol(-1).

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“…27,30 The ␣-Fe nanocrystals induced by HPTD in the amorphous Nd 9 Fe 85 B 6 matrix possess a large lattice strain of = 0.7% -0.9% ͓see Fig. The values b = 3 and c = 0.5 and 1 are used to calculate the E n for the ␣-Fe and Nd 2 Fe 14 B phases, respectively, by assuming a diffusion-controlled growth for ␣-Fe nanocrystals and an interface-controlled growth for Nd 2 Fe 14 B nanocrystals in which a fixed ratio of 2:14:1 between Nd, Fe, and B atoms is necessary.…”

Section: Growth Of Nanocrystals In Amorphous Nd 9 Fe 85 B 6 Subjecmentioning

confidence: 99%

Nanocrystallization and magnetic properties of amorphous Nd9Fe85B6 subjected to high-pressure torsion deformation upon annealing

Nan

et al. 2008

Journal of Applied Physics

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A high number density ͑ϳ10 23 m −3 ͒ of ␣-Fe nanocrystals with a size below 10 nm has been induced in amorphous Nd 9 Fe 85 B 6 by high-pressure torsion deformation ͑HPTD͒ at room temperature. The amorphous Nd 9 Fe 85 B 6 subjected to HPTD presents a quite different crystallization behavior as compared with the nondeformed alloy. The growth activation energies E g = 0.9 eV for ␣-Fe nanocrystals and 0.5 eV for Nd 2 Fe 14 B nanocrystals are determined from the annealing time dependence of their size. The ␣-Fe/ Nd 2 Fe 14 B nanocomposite magnets prepared by the combination of HPTD and subsequent thermal annealing show enhanced magnetic properties due to a small grain size as compared with the magnets prepared by directly annealing amorphous Nd 9 Fe 85 B 6 .

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Nucleation and growth processes of α-Fe nanocrystals in amorphous NdFeBCoDy: In situ x-ray diffraction studies

Cited by 11 publications

References 16 publications

Graphene with outstanding anti-irradiation capacity as multialkylated cyclopentanes additive toward space application

Graphene with outstanding anti-irradiation capacity as multialkylated cyclopentanes additive toward space application

In situ XRD studies of nanocrystallization of Fe-based metallic glass: a comparative study by reciprocal and direct space methods

Nanocrystallization and magnetic properties of amorphous Nd9Fe85B6 subjected to high-pressure torsion deformation upon annealing

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