Effect Of Milling Time Research Articles

Effects of Milling Time on the Hydrogen Storage Properties of Mg-based Transition Metals-added Alloys

In this work, Mg was employed as a starting material. Ni, Fe and Ti were selected as additives to improve hydriding and dehydriding rates of Mg. A 90 wt.% Mg + 5 wt.% Ni + 2.5 wt.% Fe + 2.5 wt.% Ti sample [named 90Mg-Ni-Fe-Ti (8 h)] was prepared by mechanical grinding under H2 atmosphere (reactive mechanical grinding) for 8 h, using a planetary ball mill. The hydrogen-storage properties of the prepared sample were then investigated and were compared with those of a 90 wt % Mg + 5 wt.% Ni + 2.5 wt.% Fe + 2.5 wt.% Ti sample previously studied by preparing via reactive mechanical grinding for 4 h [named 90Mg-Ni-Fe-Ti (4 h)]. Reactive mechanical grinding for a longer time (for 8 h), compared with that for 4 h, intensified its effects of reactive mechanical grinding. After activation, 90Mg-Ni-Fe-Ti (4 h) had higher initial hydriding and dehydriding rates and larger quantities of hydrogen absorbed and released for 60 min than 90Mg-Ni-Fe-Ti (8 h). Prolonged milling (for example, for 8 h) is considered to bring about coalescence of particles which is caused by severe plastic deformation of ductile Mg particles. The stronger effect of hydriding-dehydriding cycling and the less compact agglomeration are believed to lead to the higher initial hydriding and dehydriding rates and the larger quantities of hydrogen absorbed and released for 60 min of 90Mg-Ni-Fe-Ti (4 h) than those of 90Mg-Ni-Fe-Ti (8 h) after n = 2. DOI: http://dx.doi.org/10.5755/j01.ms.24.2.18395

Effect of Milling Time and Addition of PCA on Austenite Stability of Fe-7%Mn Alloy

Effect of Milling Time and Addition of PCA on Austenite Stability of Fe-7%Mn Alloy

Effect Of Milling Time on Particle Size of Forsterite (Mg2SiO4) from South Solok District

West Sumatra has considerable serpentine mineral resources, including the Jorong Sungai Padi Nagari Lubuak Gadang Sangir Subdistrict, South Solok District. Exploitation of minerals of serpentine is still processed in raw or semi-finished material so that it has a low selling value. Serpentine minerals contain forsterite minerals that have higher economic value if in the form of nanoparticles. The manufacture of forsterite nanoparticles has been done using synthetic materials, while synthetic materials are expensive and require a long process to make them. The treatment of temperature variations of calcination to serpentine minerals, obtained results found forsterite phase that dominates at a temperature of 800 °C. Serpentine minerals can be used as alternative ingredients for the nanoparticle makers of forsterite that are easy to find in the deep, and do not require expensive to make them. The purpose of this study was to investigate the effect of milling time on the microstructure and grain size of the serpentine forsterite mineral nanoparticles in the form of crystal structure, crystal size, and particle size. The results of the study showed grain size of 5, 10, 20, and 40 hours milling time are 579, 478, 451, and 385 nm respectively. Based on the research that has been done can be drawn conclusion Time milling effect on the grain size of forsterite mineral serpentine from South Solok District, the longer milling time the size of forsterite grains smaller. Optimum milling time to produce nano forsterite is 40 hours with a grain size of 385 nm.

The Effect of Milling Time on Properties of Magnesium-Based Composite Fabricated via Powder Metallurgy

The Effect of Milling Time on Properties of Magnesium-Based Composite Fabricated via Powder Metallurgy

The Effect of Milling Time on the Size of Silica Particles from Silica Sand

We report a method to adjust the size of silica nanoparticles from silica sand. In this study, synthesized silica nanoparticles by sol gel process from silica sand were conducted, with previously was controlled the size of silica sand by mechanical milling. Silica sand was milled by High Energy Milling in order to reduce the size into powder form. Effect of milling time shown the content of sodium and silicon is increased in sodium silicate solution obtained from various times of silica sand milling (30, 60 and 90 minutes, respectively) which is reacted with sodium hydroxide 8 M. The result of silica nanoparticles from sol gel process of sodium silicate solution were characterized using atomic absorption spectroscopy, scanning electron microscopy and X-ray diffraction techniques. It was found that the size of silica nanoparticles could be tailored with the change of milling time.

The effect of prolonged milling time on comminution of quartz

The effect of prolonged milling on quartz has been investigated by conventional ball milling. The milling efficiency was enhanced by a proper selection of grinding media (alumina), ball containing fraction, initial particle size and amount of quartz being ground. The milling was carried out in 72 h cycles (total milling time 360 h) under constant operational mill speed of 130 rpm. The effect of milling time on particle size, morphology, purity, and microstructure of quartz was examined. Results indicate that particle size reduced by >96%. It is also found that lattice strain and dislocation density increased while crystallite size decreased substantially as a function of milling time. The change in particle shape from elongated flake to spherical along with relative size determine the shape of particle size distribution curve, uniformity of lattice strain and extent of alumina contamination. The alumina contamination reported for longest milling duration is <3.3% and insignificant during the early stage of milling. The prolonged milling effects on particle size, morphology, purity, and microstructure of quartz enormously under applied milling conditions.

Effect of Milling Time on Surface Morphology of AISI O1

AISI O1 was processed by surface milling and the influence of milling time on the surface morphology was studied by 3D profilometer and scanning electron microscopy (SEM). Results show that when AISI O1 specimens are processed with various milling time, the morphology of AISI O1 changes correspondingly. Moreover, it demonstrates that the initial increase in milling time accompanies with the increase in surface roughness until the milling time reaches 60 min at which the surface roughness is the minimum

The effect of Milling time, Milling Speed and Ball to Powder Weight Ratio on the Physical Properties of Submicron Al2O3 Ceramic Particles Fabricated by Mechanical milling Method

The effect of Milling time, Milling Speed and Ball to Powder Weight Ratio on the Physical Properties of Submicron Al2O3 Ceramic Particles Fabricated by Mechanical milling Method

Dense zircon (ZrSiO4) ceramics by a simple milling-sintering route

In this work, a simple milling sintering route (pressure less) to process dense zircon ceramics from fine (D50 0.8 ?m) zircon powders is explored. Particularly, the milling time effect (0-120 min) and the maximum sintering temperature (1400-1600?C) were studied. The sintering grade developed microstructure and Vickers hardness (Hv) were evaluated and correlated. The dissociation of silicate into (monoclinic and tetragonal) zirconia and silica was evaluated by X-ray diffraction followed by the Rietveld method; it was found to be below 10 wt% in all the studied ranges. The sintering was enhanced by the milling pretreatment. No sintering additives were incorporated. Dense zircon (porosity below 1%) ceramics were obtained by a simple milling-sintering route of this high refractory powder at 100-200?C below the sintering temperature used with conventional processing routes to obtain equivalent final properties. The Vickers hardness reached: 9.0 GPa.

Effect of Milling Time on the Microstructure, Physical and Mechanical Properties of Al-Al₂O₃ Nanocomposite Synthesized by Ball Milling and Powder Metallurgy.

The effect of milling time on the morphology, microstructure, physical and mechanical properties of pure Al-5 wt % Al2O3 (Al-5Al2O3) has been investigated. Al-5Al2O3 nanocomposites were fabricated using ball milling in a powder metallurgy route. The increase in the milling time resulted in the homogenous dispersion of 5 wt % Al2O3 nanoparticles, the reduction of particle clustering, and the reduction of distances between the composite particles. The significant grain refining during milling was revealed which showed as a reduction of particle size resulting from longer milling time. X-Ray diffraction (XRD) analysis of the nanocomposite powders also showed that designated ball milling contributes to the crystalline refining and accumulation of internal stress due to induced severe plastic deformation of the particles. It can be argued that these morphological and microstructural variations of nanocomposite powders induced by designated ball milling time was found to contribute to an improvement in the density, densification, micro-hardness (HV), nano-hardness (HN), and Young’s modulus (E) of Al-5Al2O3 nanocomposites. HV, HN, and E values of nanocomposites were increased by ~48%, 46%, and 40%, after 12 h of milling, respectively.

Effect of the milling time on the magnetic properties of powder compositions of the Sm2Fe17N x intermetallic compound and an Nd–Fe–B alloy

The effect of the wet milling time on the magnetic properties of powder compositions consisting of the hard magnetic Sm2Fe17N x (x = 2.9–3.0) nitride and a rapidly quenched Nd9.6Fe76.3Co4.3Zr3.4B6.4 (at %) alloy, which are taken in different mass proportions, is studied. The compositions containing no more than 20 wt % alloy are found to exhibit a substantial increase in the magnetic characteristics as compared to those of the nitride. It is shown that the determining effect on the coercivity is related to the degree of structural imperfection of Nd–Fe–B powders, whereas the specific remanent magnetization and the specific magnetization in a field of 2 T are determined by the corresponding characteristics of the alloy. The optimum composition and efficient treatment conditions for powder mixtures are determined.

Effect of Milling times and Carbon content on Structural and Magnetic properties of Fe-Mn Alloys

The structural and the magnetic properties of nanocrystalline Fe47.5Mn47.5C5 alloys were prepared by using a mechanical alloying technique, used the commercial Fe, Mn, and C powders as precursors. It was studied in detail as function of the milling times of 1- to 48 hrs. The structural analysis based on X-ray diffraction and extended X-ray absorption fine structure spectroscopy revealed that the alloying process took place after 36 hrs milling. Concerning the magnetic behavior, the data obtained from a vibrating sample magnetometer showed that both the magnetic saturation and the coercivity depended strongly on the milling time and the crystallite size. With these results, by adjusting the milling time shows that an appropriate structural transformation and appropriate magnetization value.

An investigation of the effect of high-energy milling time of Ti6Al4V biomaterial on the wear performance in the simulated body fluid environment

ABSTRACTIn this study, the effect of milling time on wear behaviour of the Ti6Al4V alloy produced with the high-energy milling method was investigated. The Ti6Al4V alloy was milled at five different milling times in a mechanical alloying device. The milled powders were cold-pressed under 620 MPa pressure, sintered at 1300°C for 2 h and cooled to room temperature in the furnace. The sintered alloys were characterised with SEM, XRD and hardness and density measurements. Wear tests were performed using a pin-on-disc type wear testing device, under three different loads, at four different sliding distances in simulated body fluid environment. Results showed a decreasing powder size with increasing milling time. The highest decline in size occurred for the powders milled for 120 min. The result of hardness measurements and wear tests showed that samples milled for 120 min had both the highest hardness value and the lowest weight loss.

The Effect of Milling Time on the Microstructural Characteristics and Strengthening Mechanisms of NiMo-SiC Alloys Prepared via Powder Metallurgy.

A new generation of alloys, which rely on a combination of various strengthening mechanisms, has been developed for application in molten salt nuclear reactors. In the current study, a battery of dispersion and precipitation-strengthened (DPS) NiMo-based alloys containing varying amounts of SiC (0.5–2.5 wt %) were prepared from Ni-Mo-SiC powder mixture via a mechanical alloying (MA) route followed by spark plasma sintering (SPS) and rapid cooling. Neutron Powder Diffraction (NPD), Electron Back Scattering Diffraction (EBSD), and Transmission Electron Microscopy (TEM) were employed in the characterization of the microstructural properties of these in-house prepared NiMo-SiC DPS alloys. The study showed that uniformly-dispersed SiC particles provide dispersion strengthening, the precipitation of nano-scale Ni3Si particles provides precipitation strengthening, and the solid-solution of Mo in the Ni matrix provides solid-solution strengthening. It was further shown that the milling time has significant effects on the microstructural characteristics of these alloys. Increased milling time seems to limit the grain growth of the NiMo matrix by producing well-dispersed Mo2C particles during sintering. The amount of grain boundaries greatly increases the Hall–Petch strengthening, resulting in significantly higher strength in the case of 48-h-milled NiMo-SiC DPS alloys compared with the 8-h-milled alloys. However, it was also shown that the total elongation is considerably reduced in the 48-h-milled NiMo-SiC DPS alloy due to high porosity. The porosity is a result of cold welding of the powder mixture during the extended milling process.

Milling time effect of Reactive Hydride Composites of NaF[sbnd]NaH[sbnd]MgB2 investigated by in situ powder diffraction

Light metal complex borohydrides have high hydrogen storage capacities but suffer from drawbacks of slow hydrogen sorption kinetics, poor reversibility and high thermodynamic stability. The NaF+9NaH+5MgB2 composite has a theoretical hydrogen capacity of 7.7 wt% H assuming the formation of 10NaBH3.9F0.1+5MgH2. Hydrogenation and dehydrogenation properties as well as the effect of different ball milling times have been investigated. The in situ hydrogenation is faster in the composite ball milled for 87 h than the 5 h milled composite. A boron-rich phase with space group Pa-3, a = 7.4124(5) Å was formed during hydrogenation at 325 °C and 50 bar hydrogen for both short and long milling times. In the long milled composite the boron-rich phase disappeared after 3 h of hydrogenation, whereas it became a major phase in the short milled composite after 1.5 h of hydrogenation. NaBH4 was formed at 206 °C. NaMgH1-xFx was formed at 290 °C instead of the assumed MgH2. The same phases formed at 268 °C and 325 °C, respectively, and only in minor amounts in the short milled composite. Ex situ hydrogenation in a Sieverts' type apparatus at the same temperature and hydrogen pressure conditions followed a different reaction pathway with formation of MgH2 in addition to NaBH4 and NaMgH3-xFx (0 ≤ x ≤ 1). The measured hydrogen uptake was 6.0 and 6.3 wt% for the long and short milled composites, respectively.

Effect of Milling Time on the Properties of BYF Doped PZT Energy Harvesting Ceramics by High-Energy Ball Milling

Recently, Lead Zirconate Titanate (PZT) has been attracted for energy harvesting (EH) devices because of their excellent piezoelectric properties at the morphotropic phase boundary (MPB). The EH devices require high energy density related to high figure of merit (FOM: g33 x d33). As a result, the improvement of piezoelectric voltage coefficient (g33) and piezoelectric charge coefficient (d33) to better energy density property obtained should be searching for. Therefore, PZT-BYF system was chosen for piezoelectric energy harvester by focusing to study on the composition of 0.99PZT-0.01BYF (0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y0.7Fe0.3)O3). In this study, PZT and BYF systems were calcined separately and then 0.99PZT-0.01BYF powders were prepared by solid state method and mixed via high-energy ball milling in various milling time (2, 4, 10 and 16 hrs). The effect of milling time on the physical and electrical properties, figure of merit and microstructure were investigated.

Synthesis of Biodegradable Mg-Zn Alloy by Mechanical Alloying: Effect of Milling Time

Magnesium (Mg) is one such promising light weight metal, which is currently utilized for bio-engineering applications. Mg possesses a number of attractive characteristics that make Mg-based materials potential candidates to serve as implants for load-bearing applications in the medical industry due to its good biocompatibility and biodegradability. However, Mg and its alloys are susceptible to suffer attack in chloride containing solutions, e.g. the human body fluid or blood plasma. Thus, alloying with other metal elements is the most effective tool to improve mechanical properties and corrosion resistance of Mg. In this current work, binary Mg-Zn alloy was produced using mechanical alloying (MA) followed by compaction and sintering. The aim of this work was to study the effect of milling time on binary magnesium-zinc (Mg-Zn) alloy synthesized by mechanical alloying. A powder mixture of Mg and Zn with the composition of Mg-10wt%Zn was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 250rpm for various milling times i.e. 1, 2, 5, 10 and 15hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400MPa and sintered in a tube furnace at 350°C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Zn solid solution and formation of MgZn2 when Mg-Zn powder was mechanically milled for 2hours and further. A prolonged milling time has increased the density and microhardness of the sintered Mg-Zn alloy.

Effect of Milling Time on the Microstructure and Thermoelectric Properties of P‐type TAGS‐90 Alloys by HEM and SPS

In this study, p‐type TAGS‐90 powders were fabricated using high‐energy milling (HEM), subsequently sintered by spark plasma sintering (SPS). And then, the effects of milling time on the microstructure, mechanical, and thermoelectric properties were investigated. The powders were quickly decreased to fine particles of ~1 μm in size and uniformly agglomerated with the increasing of milling time. XRD results indicated that all milled powders and SPSed samples showed single GeTe phase. Also, EDX results showed almost no contamination and exact composition after milling. The maximum figure of merit, ZT = 1.08, was obtained for 30‐min‐milled sample at 723 K.

The Effect of Milling Time and Sintering Temperature on Crystallization of BaFe12O19Phase and Magnetic Properties of Ba-Hexaferrite Magnet

The Effect of Milling Time and Sintering Temperature on Crystallization of BaFe₁₂O₁₉Phase and Magnetic Properties of Ba-Hexaferrite Magnet

The Effect of Milling Time and Sintering Temperature on Synthesis of PbTiO&lt;sub&gt;3&lt;/sub&gt; by Mechanical Alloying

PbTiO3 is one of electroceramic materials which can be applied for electronics and microelectronics due to their dielectric, pyroelectric, and piezoelectric properties. The members of PbTiO3-based ferroelectrics are widely used in multilayer, actuator and sensor capacitor. At room temperature, PbTiO3 has a tetragonal perovskite structure. In this research, PbTiO3 particles are synthesized by mechanical alloying method with variation of milling time and sintering temperature. The milling time variation is taken for 10, 20 and 30 hours. Sintering temperature variation is performed at 850, 900 and 1000°C. The powders used in the milling process are PbO and TiO2 powders. X-Ray Diffraction (XRD) and Scanning Electron Microscopy–Electron Difraction X-ray (SEM-EDX) are performed to analyze the formation of PbTiO3 phase. It is found that the synthesized powders contain 100% PbTiO3 phase for all sintering temperatures. The PbTiO3 particles have agglomeration shape with a broad particle size. The electrical properties of PbTiO3 are measured using electrical test device. Electricity test analysis shows that the synthesized PbTiO3 behaves as semiconductor-like.