Dependence of the Mean Grain Size and Coercivity of Sintered Nd–Fe–B Magnets on the Initial Powder Particle Size

2006 ◽  
Vol 42 (10) ◽  
pp. 2897-2899 ◽  
Author(s):  
K. Uestuener ◽  
M. Katter ◽  
W. Rodewald
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Powder Particle ◽  
Powder Particle Size ◽  
Initial Powder ◽  
Mean Grain Size ◽  
The Mean

scholarly journals Paleolimnology of Lake Yamanaka as reflected on particle-size distribution

1970 ◽  
Vol 14 ◽  
pp. 35-42 ◽  
Author(s):  
Danda Pani Adhikari
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Size Distribution ◽  
Central Japan ◽  
Size Frequency Distribution ◽  
Factors Affecting ◽  
Mean Grain Size ◽  
The Mean ◽  
Main Factors ◽  
Lake Size

A 17.63 m long bore-hole core extracted from the deepest part of Lake Yamanaka, one of the Fuji-five Lakes at the northeasternfoot of Mount Fuji, central Japan, composed of sediment with intercalations of scoria fallout deposits. The sediment of the upper11.4 m was investigated for grain-size distribution by using a laser diffraction particle size analyser. The mean grain-size profileshowed various degrees of fluctuations, both short-and long-terms, and the size-frequency distribution revealed unimodal-trimodalmixing of sediments. Changes in lake size and water depth appear to be the main factors affecting the variability in the grain-sizedistribution and properties. The lake level appears low during 7000–5000 cal BP and 2800–1150 cal BP and relatively high during5000–2800 cal BP and 1150 cal BP– present.DOI: http://dx.doi.org/10.3126/bdg.v14i0.5437Bulletin of the Department of Geology Vol.14 2011, pp.35-42 

Preparing Superfine Quartz Sand Powder by Ball Milling Method

2014 ◽  
Vol 1058 ◽  
pp. 44-47
Author(s):  
Bo Feng Ma ◽  
Bin Tan ◽  
Wen Bo Zhao ◽  
Xin Liang ◽  
Fa Mei Hu ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Ball Milling ◽  
Quartz Sand ◽  
Milling Time ◽  
Mean Particle Size ◽  
Mean Grain Size ◽  
Planetary Ball Milling ◽  
The Mean ◽  
Ball Milling Time

To save land resources by the use of low-grade natural resources to realize a high cost performance product, the technology of prepared superfine quartz sand powder via the ball milling methods were investigated. The results are shown the mean particle size of quartz sand powder is gradually become small varied with prolonging the ball milling time. Before 60 minutes, the mean particle size is slashed, however, the range of varying mean particle size is less after 60 minutes under the ball milling rotate speed for 200r/min and the charge amount for 200g/L, so the ball milling time for 60 minutes is decided.The mean grain size of quartz powders are decreased vary with an increasing the ball milling rotate speed, and the rotate speed is lower, the distribution is wider, however, the rotate speed is higher, the distribution is narrower.The mean grain size of quartz powders are 11.25μm via a roller ball milling, the mean grain size of quartz powders are 7.37μm via a planetary ball milling, and the particle size distribution of quartz powders milled via a roller ball milling is wider than that of quartz powders milled via a planetary ball milling, which shows the of quartz powders milled via a roller ball milling is not more uniform than that of quartz powders milled via a planetary ball milling, the asymmetry powder is advantage for forming the high performance building materials body.

Influence of initial powder particle size on yttrium stabilized zirconium thin films formed by e-beam technique

2011 ◽  
Vol 188 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Giedrius Laukaitis ◽  
Darius Virbukas ◽  
Julius Dudonis ◽  
Oresta Katkauskė ◽  
Darius Milčius
Keyword(s):  
Thin Films ◽  
Particle Size ◽  
Powder Particle ◽  
Powder Particle Size ◽  
Initial Powder ◽  
Beam Technique

Influence of Nickel Powder Particle Size on the Microstructure and Densification of Spark Plasma Sintered Nickel-Based Superalloy

2021 ◽  
Vol 53 ◽  
pp. 1-19
Author(s):  
Olugbenga Ogunbiyi ◽  
Tamba Jamiru ◽  
Rotimi Sadiku ◽  
Oluwagbenga Adesina ◽  
Olanrewaju Seun Adesina ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Powder Particle ◽  
Nickel Particle ◽  
Sintered Alloy ◽  
Powder Particle Size ◽  
Localized Deformation ◽  
The Matrix ◽  
Spark Plasma ◽  
Sintered Alloys

This study aims to investigate the effects of powder particle size on the densification and microhardness properties of spark plasma sintered superalloy. Three particles size ranges of nickel were used in this study, namely, (3-44, 45-106 and 106-150 μm), and this is the matrix in the IN738LC superalloy composition (powder), used in the study. The effects of the particle size were examined at a specific applied temperature and pressure. The transitioning stages during the sintering process of the green powders to the formation of the sintered alloy were analyzed and given as the particle rearrangement stage, the localized deformation stage and the neck formation/grain growth stage. There was the formation of γ, γ' and a solid solution within the microstructure of the sintered alloys. The effect of particle size was more pronounced on the grain sizes obtained, while the phases formed is the same for the three alloys. The results indicate that the nickel particle size (>60% of the total composition) has a significant influence on the densification, porosity, grain size and hardness properties of the IN738LC sintered alloy. Finer nickel particle size resulted in a sintered product with smaller grain size (9 µm), reduced percentage porosity (3.9%), increased relative density (96.1%) and increased hardness properties (371 Hv).

scholarly journals Preparation of Continuous Alumina Fiber with Nano Grains by the Addition of Iron Sol

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5442
Author(s):  
Luqun Liu ◽  
Juan Wang ◽  
Yunzhu Ma ◽  
Wensheng Liu ◽  
Shuwei Yao
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Colloidal Particle ◽  
Sol Gel ◽  
Nucleating Agent ◽  
Alumina Fiber ◽  
Mean Grain Size ◽  
The Mean ◽  
Α Al2o3 ◽  
Holding Temperature

Continuous alumina fiber exhibits excellent mechanical properties owing to its dense microstructure with fine grains. In this study, alumina fiber was prepared by the sol–gel method using iron sol as a nucleating agent. It was proposed that the α-Al2O3 grain size be adjusted based on the modification of colloidal particle size. The effect of holding temperature and reaction material ratio on the iron colloidal particle size was studied. The microstructure of alumina fiber was characterized by scanning electron microscopy (SEM). The experiment results indicated that iron colloidal particle size increases with the holding temperature and the NH4HCO3/Fe(NO3)3·9H2O ratio. The alumina fiber with uniform nano α-Al2O3 grains was obtained by calcination at 1400 °C for 5 min. The mean grain size tends to rise with the mean colloidal particle size. Using the iron sol as a nucleating agent, the fiber with a mean grain size of 22.5 nm could be formed. The tensile strength of fibers increased with the decrease of grain size.

scholarly journals Powder Particle Size Effects on Microstructure and Mechanical Properties of Mechanically Alloyed ODS Ferritic Steels

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 69
Author(s):  
Moisés Oñoro ◽  
Julio Macías-Delgado ◽  
María A. Auger ◽  
Jan Hoffmann ◽  
Vanessa de Castro ◽  
...  
Keyword(s):  
Particle Size ◽  
Powder Particle ◽  
Fusion Energy ◽  
Industrial Applications ◽  
Processing Route ◽  
Powder Particle Size ◽  
Powder Size ◽  
Strengthening Effect ◽  
Initial Powder ◽  
Secondary Phases

Reduced activation ferritic (RAF) steels are expected to be widely used in challenging nuclear industrial applications under severe thermo-mechanical regimes and intense neutron loads. Therefore, actual research panorama is facing the strengthening strategies necessary to maximize both performance and endurance under these conditions. Oxide dispersion strengthened (ODS) RAF steels are leader candidates as structural materials in fusion energy reactors thanks to the reinforcement obtained with a fine dispersion of nanosized oxides in their matrix. In this study, the influence of the initial powder particle size and the selected processing route on the final material has been investigated. Two RAF ODS steels coming from atomized pre-alloyed powders with nominal particle powder sizes of 70 and 30 µm and composition Fe-14Cr-2W-0.4Ti-0.3Y2O3 (wt. %) were manufactured by mechanical alloying. Alloyed powders were compacted by hot isostatic pressing, hot crossed rolled, and annealed at 1273 K. Initial powder particle size differences minimize after milling. Both steels present an almost completely recrystallized material and similar grain sizes. The same type and distributions of secondary phases, Cr-W-rich, Ti-rich, and Y-Ti oxide nanoparticles, have been also characterized by transmission electron microscopy (TEM) in both alloy samples. The strengthening effect has been confirmed by tensile and Charpy impact tests. The two alloys present similar strength values with slightly better ductile brittle transition temperature (DBTT) and ductility for the steel produced with the smaller powder size.

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