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An intermetallic compound c –NiZr and a mixture of elemental powders of nickel and zirconium [Ni 50 Zr 50 (at. %)] have been mechanically ground (MG) and mechanically alloyed (MA), respectively, using a high-energy ball mill in various atmospheres. The products were characterized by x-ray diffraction, transmission electron microscopy, differential scanning …
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The kinetics of amorphization during ball milling is generally analyzed using two different approaches: the classical Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory and Delogu and Cocco's model for which a region deterministically transforms after it reaches a certain number of collisions. The application of JMAK analysis to the latter model predicts Avrami exponents to …
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The ball to powder ratio loaded into the vial was 10:1 in mass. A planetary ball mill with rotational speed of 200 rpm was used. The weight of the powder mixture was 15 g in all cases, and in order to prevent samples from oxidation, the milling process was carried out in an argon atmosphere.
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Amorphization by mechanical milling (MM), where a single composition (e.g. intermetallic compound) is milled requires the accumulation of defects to induce the transformation. It is concluded that anti-site chemical disorder and nanocrystalline grain boundaries are the important defects in this regard.
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The I 2-sorption and -retention properties of several existing zeolitic imidazolate frameworks (ZIF-4, -8, -69) and a novel framework, ZIF-mnIm ([Zn(mnIm) 2]; mnIm=4-methyl-5-nitroimidazolate), have been characterised using microanalysis, thermogravimetric analysis and X-ray diffraction.The topologically identical ZIF-8 ([Zn(mIm) 2]; mIm=2-methylimidazolate) and …
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The amorphous solid was prepared by milling the crystalline solid using a planetary ball mill (P-6; Fritsch, Idar-Oberstein, Germany) in agate ball mill pot (250 ml in volume) with 22 agate balls (the diameter and number of balls were: 8 mm Φ × 5, 10 mm Φ × 7, 18 mm Φ × 10).
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The purposes of this study were to clarify the amorphization by ball milling of atorvastatin calcium sesquihydrate (AT) and to analyse the change in dissolution kinetics. Methods The amorphous AT was prepared from crystal AT by ball milling and analysed in terms of the changes of its physicochemical properties by powder X-ray diffraction ...
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Abstract We present a new approach, namely ball milling, to synthesize amorphous boron nitride ( a -BN). The amorphization kinetics are revealed by X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS).
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X-ray diffraction has been used to investigate the kinetics of amorphization through ball-milling at 20 Hz, for five zeolitic imidazolate frameworks (ZIFs) – ZIF-8, ZIF-4, ZIF-zni, BIF-1-Li and CdIF-1. We find that the rates of amorphization for the zinc-containing ZIFs increase with increasing solvent acces In celebration of Tony Cheetham's 70th birthday Flexibility and Disorder in Metal ...
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This suggests that amorphization in metal-metalloid systems, i.e. ductile-brittle systems, like Fe40Ni40P14B6 is fully achieved by ball milling alone using high milling energy and metalloid ...
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Ball-milling-induced amorphization in Ni x Zr y compounds: A parametric study Y. Chen, M. Bibole, R. Le Hazif, and G. Martin Phys. Rev. B 48, 14 – Published 1 July 1993
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A proposed microstructural mechanism is shown in fig. S6. Similar phenomenon has been observed in extreme deformation of brittle materials (23–27) and takes place during processes such as ball milling . The versatility and synergy of deformation mechanisms in HEAs render them as viable candidates for extreme load-bearing applications such as ...
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ball milling as a non-equilibrium processing method which can be analogous to rapid solidification. This review will first describe the equipment and some of the process va-riables used for high energy ball milling. Next, the physics of the milling processes has been described to the extent
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Weeber and Bakker [8] have recently reviewed amorphization by ball milling. Two major categories of amorphization by ball milling can be identified: 1. Mechanical alloying (MA) of elemental (or dissimilar alloy) powders involving material transfer between the components, and 2.
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Herein, we present a study of the impact of the jar and ball medium on the performance in the mechanochemical amorphization of chitin. We measured the crystallinity index of chitin after milling it in a vibration mill in an apparatus made of copper, aluminum, brass, tungsten carbide, zirconia, stain …
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Ball-milling Following the protocol of Hempel et al. (2020a), the particle size of bulk IND was reduced by ball milling at 30 Hz for 1 min in a cold room (5 °C) using an oscillatory ball mill (Mixer Mill MW400, Retsch & Co., Haan, Germany) with a pair of jars (25 mL) and two stainless steel balls (12 mm in diameter) for each jar.
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The SHMM provides higher efficient and instant way of amorphization of rice starch compared to conventional methods as pressure treatment, ball milling treatment, and so on. In this study, the milling temperature and initial moisture content of the tapioca starch are varied, respectively, as 80 °C, 100 °C, and 120 °C and 10%, 12%, and 14% ...
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Structural changes occurring in the crystalline element selenium upon high-energy ball milling has been studied. Milling experiments have been performed at the ambient temperature and at a cryogenic temperature of -100 °C, respectively. The final milling products under both conditions were found to be a fully amorphous phase after several hours of mechanical milling.
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In this way the amorphization process by ball-milling can be seen as a continuous increase in the volume fraction of zones with local disorder of the crystallographic structures.
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We report the rapid amorphization of the prototypical substituted zeolitic imidazolate framework, ZIF-8, by ball-milling. The resultant amorphous ZIF-8 (amZIF-8) possesses a continuous random network (CRN) topology with a higher density and a lower porosity than its crystalline counterpart. A decrease in the In celebration of Tony Cheetham's 70th birthday
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In this way the amorphization process by ball-milling can be seen as a continuous increase in the volume fraction of zones with local disorder of the crystallographic structures.
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nism of amorphization by MG of intermetallics is still not well understood. MA and MG are usually carried out using a high-energy ball mill in an inert gas atmo-sphere. Recently, the present authors have demonstrated that an amorphous nitride a-TiZrN0.3 is synthesized by MA and the chemical reaction between N2 and Ti
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The purpose of this study was to investigate the effect of working volume in the high-energy ball-milling process on the breakage characteristics (i.e., particle size, morphology, and chemical composition) and adsorption performance of rice straw ash. This study was conducted to confirm working volume issue since this parameter has correlations with the …
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The main problem of using ball milling for the amorphization of cellulose is the high cost of this process, estimated at $ 10–15 per kg. In addition, the obtained amorphized cellulose has an unstable phase state and recrystallizes in a humid atmosphere or …
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[17] Weeber A W and Bakker H 1988 Amorphization by ball milling—a review Physica B 153 93–135. Go to reference in chapter Crossref [18] Hong L B and Fultz B 1996 Two-phase coexistence in Fe–Ni alloys synthesized by ball milling J. Appl. Phys. 79 3946–55
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When the ball milling process starts, ASR particles are subjected to high energetic collisions that may promote both aggregation and breaking processes as well as an accumulation of crystalline defects and vacancy amorphization (Fig. 7(b)) (Lu et al. 1997; Montinaro et al. 2007). The aggregation phenomenon with the subsequent formation of ...
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Amorphization of metallic titanium by ball milling was presented. With the introduction of continuous pickup of impurities, hexagonally close-packed (hcp) titanium transformed gradually into an amorphous phase without experiencing any intermediate stage of forming a detectable metastable compound phase. The crystallization temperature of the …
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Amorphization of ZIF-8 and another isostructural MOF, ZIF-mnIm (Zn (mnIm) 2 where mnIm = 4-methyl-5-nitroimidazolate), during ball milling 85 also significantly enhances their iodine retention abilities, particularly in the case of ZIF-mnIm.
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Amorphization by ball milling. A review Weeber, A. W.; Bakker, H. Abstract. A new method for the preparation of amorphous alloys is the mechanical alloying process. So far, three amorphization reaction types were observed when this technique is used.
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alongside a 10 mm stainless steel milling ball at room temperature and sealed properly. This combination was then subjected to 30 Hz milling in a Retsch MM400 grinder mill for varying times. After milling, the amorphous milling products were recovered and characterized. SI-2: Ball-milling Amorphization
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