CO sensitive nanocrystalline LaCoO3 perovskite sensor ...
High energy ball milling (HEBM) is another promising synthesis route capable of synthesizing nanostructured mixed oxides at quasi room temperature. Mechanical impact during the process reduces the precursors' crystallite size to nano scale, provides a homogeneous mixture, and enhances the solid state diffusion.
Atomic-scale structure of nanocrystalline ${mat{ZrO ...
The atomic-scale structure of nanocrystalline ZrO 2 obtained by ball milling has been studied using high-energy x-ray diffraction and the atomic pair distribution function technique. The studies show that, upon relatively short milling times, the parent crystalline material, monoclinic ZrO 2, evolves into a nanocrystalline phase that is locally similar to …
Nanocrystalline metals prepared by low energy ball milling ...
The influence of low energy ball milling on the crystallite size, lattice strain, and storage of deformation energies of elemental metal powders is studied. The formation of nanosized grains (5–25 nm) and enhancement of lattice strain up to 0.4% is found. Excess enthalpies of up to 25% of the heat of fusion are reached.
Porous Nanocrystalline Alloys Prepared by High Energy Ball ...
Hydrogen Storage Properties of Nanocrystalline Mg 2 Ni x Cu 1-x Synthesized by Mechanical Alloying p.1049 Porous Nanocrystalline Alloys Prepared by High Energy Ball Milling
Contamination Effects on Improving the Hydrogenation ...
Abstract: Ultrafine MgH2 nanocrystalline powders were prepared by reactive ball milling of elemental Mg powders after 200 h of high-energy ball milling under a hydrogen gas pressure of 50 bar. The as-prepared metal hydride powders were contaminated with …
PREPARING NANO-CRYSTALLINE La DOPED WC/Co POWDER BY HIGH ...
preparing nano-crystalline la doped wc/co powder by high energy ball milling >The La doped WC/Co powder was prepared by high energy ball milling. The changes of crystal structure, micrograph and defect of the powder were investigated by means of XRD (X-ray diffraction), SEM (scanning electron microscope) and DTA (differential thermal analysis).
Sintering Behavior of Nanocrystalline Al6063 Powders ...
Nanocrystalline Al6063 powders were synthesized by high-energy mechanical milling of gas-atomized powders for 22.5 h. The powders were uniaxially compacted at various compaction pressures ranging 200–1325 MPa and then were sintered at temperatures between 550 and 650 °C for 1 h. The densification and microstructural evolutions during both solid …
Microstructural characterization of nanocrystalline SiC ...
The nanocrystalline cubic SiC phase is prepared by mechano-synthesis of stoichiometric mixture of Si and graphite powders under argon in a high-energy ball mill. Formation of the thin graphite layer and amorphous Si are noticed within 3 h of milling.
Solid state consolidation nanocrystalline copper-tungsten ...
Nanocrystalline metal powders synthesized by mechanical alloying in a ball mill resulted in micron-sized powder particles with a nanosized (5 to 25 nm) substructure. ... {sub 2}-(Al,Cr){sub 3}Ti intermetallic compounds, which were prepared by high energy ball milling, was analyzed. Particular attention was paid to the development of the ...
Nanocrystalline Oxide Ceramics Prepared by High-Energy ...
Nanocrystalline (n) LiNbO3 was prepared by high-energy ball milling from the polycrystalline (p) material. Grain sizes were determined by XRD measurements and TEM images; thermal stability ranges ...
Effect of nano TiN/Ti refiner addition content on the ...
Abstract A novel grain refiner consisting of nanoparticulate TiN suspended in a Ti metal powder (abbr. TiN/Ti refiner) was prepared by high energy ball milling. The effect of the TiN/Ti refiner addition contents on microstructures and properties of Al-Zn-Mg-Cu alloy was investigated in detail. The results show that the TiN/Ti refiner addition changes the α(Al) matrix morphology of …
Transformation of Goethite to Hematite Nanocrystallines by ...
Conclusion. α -Fe 2 O 3 nanocrystalline was successfully prepared by high-energy ball milling of goethite ( α -FeOOH) powder after 40 hours of milling. The mechanochemical effect induced by high energy ball milling induced dehydration and transformation of goethite to hematite. This work shows that this method is environmentally …
(PDF) CO sensitive nanocrystalline LaCoO3 perovskite ...
The high energy milling was performed at 1000 rpm for 2 h. The as-milled powders were highly agglomerated with a low SSA (<4 m 2 /g). A second milling step with lower energy and different milling times was performed in order to increase the specific surface area. A laboratory attritor containing 4.5 mm hardened steel balls was used in this step.
Microstructural and mechanical study of nanocrystalline ...
the objectives of the present work are (i) to produce nanocrystalline (ti 0.8 w 0.2 )c by high-energy ball milling the elemental ti, w and c (graphite) powders at room temperature, (ii) to characterize the microstructure evolution of the prepared materials in terms of crystallite size and strain and (iii) finally to explain the relationship …
Impact behavior and constitutive model of nanocrystalline ...
To investigate mechanical properties and deformation mechanisms of nanocrystalline materials under high strain rate, dynamic impact tests for nanocrystalline Ni bulk prepared by high-energy ball milling combined with compaction and hot-pressure sintering were carried out under different high strain rates on Split Hopkinson bar.
Nanocrystalline Materials: Synthesis, Characterization ...
Thermal stability of nanocrystalline Al-5at.%Ni and Al-5at.%V alloys produced by high-energy ball milling journal, May 2018 Esquivel, J.; Wachowiak, M. G.; O'Brien, S. P. Journal of Alloys and Compounds, Vol. 744
Structure and magnetic properties of nanocrystalline ...
In this current study, nanocrystalline Dy powders were prepared by melt-spinning and subsequent high-energy ball-milling. The effect of ball-milling time on the structure and magnetic properties of the powders was studied. The crystal structure and microstructure of the melt-spun ribbons and ball-milled powders were observed by X-ray …
Nanocrystalline metals prepared by high-energy ball ...
12%Pure metals with body-centered cubic (bcc) and hexagonal close-packed (hcp) structures are subjected to ball milling, resulting in a decrease of the average grain size to ≈9 nm for metals with bcc and to ≈13 nm for metals with hcp crystal structures.
Grain-growth kinetics of nanocrystalline iron studied in ...
Grain growth in nanocrystalline iron prepared by mechanical attrition. Journal Article Malow, T; Koch, C - Acta Materialia. The grain growth in nanocrystalline Fe produced by high energy ball milling is investigated. Grain growth data were analyzed using two different models of grain growth, one of which takes pinning forces on the grain ...
Combustion and Ball Milled Synthesis of Rare Earth Nano ...
This paper reports a study on nanocrystalline ceria powder prepared by high energy ball-milling and combustion syn-thesis methods. The combustion synthesis was carried out using ceric ammonium nitrate as oxidizer and citric acid, glycine or citric acid plus glycine as fuel. The minimum crystallite size of ceria powder is obtained by combustion syn-
Anion diffusivity in highly conductive nanocrystalline ...
We report on the fluorine diffusivity in nanocrystalline BaF 2 and CaF 2 as well as in BaF 2:CaF 2 composites prepared by high-energy ball milling.Mechanical treatment of polycrystalline BaF 2 together with CaF 2 results in a nanocrystalline composite with an unexpectedly high dc conductivity of about 0.1 mS cm −1 at 450 K. X-ray diffraction and 19 F magic angle spinning …
Microstructure characterization of nanocrystalline Ni3C ...
Nanocrystalline non-stoichiometric cadmium ferrite (CdFe2O4) has been synthesized by high-energy ball milling the mixture (1:1 mol%) of CdO and α-Fe2O3 at room temperature.
DUGi: Ítem | Recercat - Synthesis and Characterization of ...
This work deals with the microstructural properties of the Al-20 at. % Cu alloy prepared by high-energy ball milling of elemental aluminum and copper powders. The ball milling of powders was carried out in a planetary mill in order to obtain a nanostructured Al-20 at. % Cu alloy.
CO sensitive nanocrystalline LaCoO3 perovskite sensor ...
Abstract This paper reports high energy ball milling as a promising nanostructured perovskite synthesis route to develop high sensitive and low cost nano-perovskite gas sensors. CO gas sensing properties of thick film LaCoO 3 perovskite prepared by (a) high energy ball milling, (b) sol–gel and (c) solid state reaction have been comparatively studied …
A surfactant-assisted high energy ball milling technique ...
A surfactant-assisted high energy ball milling technique to produce colloidal nanoparticles and nanocrystalline flakes in Mn–Al alloys. P. Saravanan * a, D. Deepika a, Jen-Hwa Hsu * b, V. T. P. Vinod c, Miroslav Černík c and S. V. Kamat a a Defence Metallurgical Research Laboratory, Hyderabad-500058, India. E-mail: psdrdo@gmail; [email protected] b Department of …
Investigation of typical properties of nanocrystalline ...
On the other hand, the milling time is directly related to energy use as well as the purity of the obtained powder products. This paper presents the results of investigation on some typical properties of nanocrystalline iron powders prepared by milling techniques using a Fritsch P-6 planetary ball miller.
Article Metrics | Thermal analysis investigation of ...
The hydrogen loading characteristics of nanocrystalline Mg, Mg–Ni (Ni from 0.1 to 10 at.%), and Mg–Fe (Fe from 1 to 10 at.%) alloys in 3 MPa H2 were examined using high pressure differential scanning calorimetry and thermogravimetric analysis. All samples showed rapid uptake of hydrogen. A decrease in the onset temperature for hydrogen absorption was …
Mechanochemical preparation of nanocrystalline metal ...
12%Another example is given by nanocrystalline BaF 2:CaF 2 composites (10–20 nm crystallite size) prepared by high-energy ball-milling for which DC conductivities as high as 0.1 mS cm −1 at 450 K were reported . This extraordinary conductivity was due to the diffusivity of fluorine in the composites.
Preparation of nanocrystalline materials by high-energy ...
Materials Science and Engineering A 386 (2004) 442–446 Preparation of nanocrystalline materials by high-energy milling P. Bal´azˇ a,∗, E. Godoˇc´ıkov´aa, L. Kril'ov´aa, P. Lobotkab, E. Gockc a Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04353 Koˇsice, Slovakia b Institute of Electrical Engineering, Slovak Academy of Sciences, D´ubravsk´a cesta …
Nanocrystalline Oxide Ceramics Prepared by High-Energy ...
12%We prepared various nanocrystalline ceramics by high-energy ball milling. The investigated systems are the oxide ceramics Li 2 O, LiNbO 3, LiBO 2, B 2 O 3, TiO 2 as monophase materials and the composite material Li 2 O : B 2 O 3. The average grain size was adjusted by variation of the milling time.
Milled goethite nanocrystalline for selective and fast ...
Goethite nanocrystallines powders were prepared by high-energy ball milling with a balls-to-powder mass ratio of 10:1 and for 40 h of milling. X-ray diffraction, Rietveld analysis, and vibrating sample magnetometer are used to characterize the obtained nanopowders followed by tests for toxic metals removal from aqueous solutions.
Structural, Microstructural Characterisation and Magnetic ...
The mechanical alloying experiments were performed using a faro-planetary high-energy ball mill (Retsch PM 400). In order to ensure that the milling will be performed in an inert atmosphere (no oxidation during the milling), the starting powders with five (05) stainless steel balls, having 12 mm in diameter, were sealed in atmosphere of azote ...
Hydrogenation of Nanocrystalline Mg2Ni Alloy Prepared by ...
Nanocrystalline Mg2Ni powders produced by high energy ball milling (HEBM) were subjected to further severe plastic deformation by cold rolling (CR) or equal-channel angular pressing (ECAP). The microstructure of the alloys have been analysed by the Convolutional whole profile fitting method of the X-ray line profiles. The hydrogenation behavior has been studied by …
High energy ball milling process for nanomaterial synthesis
For all nanocrystalline materials prepared by high-energy ball milling synthesis route, surface and interface contamination is a major concern. In particular, mechanical attributed contamination by the milling tools (Fe or WC) as well as ambient gas (trace impurities such as O 2, N 2 in rare gases) can be problems for high-energy ball milling.