Particle Size Of Powder Research Articles

Preparation of ultrafine Mo powder by the H2 reduction of MoO2: Parameter optimization, reaction kinetic, and its reduction mechanism

The influences of different parameters, such as reaction temperature, yttrium (Y) content, and H2 concentration, on the particle size and morphological structure of Mo powder prepared via the H2 reduction of MoO2, were investigated in the work. TG, XRD, FE-SEM, laser particle size analysis, model fitting, and orthogonal design experiment methods were adopted to analyze the reaction kinetic and reduction mechanism. The results showed that the optimum conditions for preparing ultrafine Mo powder were recognized as 1073 K, 1 mass% Y content, and a H2 concentration of 0.000576 mol·cm−2·min−1, which enabled the as-prepared Mo powder with a particle size as small as 107 nm. A new interfacial chemical reaction model with the consideration of reaction temperature, H2 concentration, and sample thickness, was proposed to analyze the reaction kinetic. It was found that the curves predicted by the model agreed well with the experimental data, with the apparent activation energy extracted to be 94.686 kJ/mol. The effect of different individual parameter on the reaction rate and the possible reduction mechanism were also elucidated.

Material Properties of Nickel Based Cold Spray by Means of Small Specimens

The article is aimed on material properties evaluation of Ni and NiCr Cold Spray layers by means of proportional small specimens. For the purpose of testing, various cold spray layers were prepared. Spraying with nozzle for inner tube application from two NiCr powders of different particle sizes and from Ni powder of one particle size was applied. In addition, spraying with nozzle type for outer tube applications from same Ni powder was applied too. The evaluation is aimed on mechanical properties and metallographic analysis of cold spray layers as received and after defined heat treatment, comparing small and standard testing specimens. It provide overview of the tensile properties at room temperature and the microstructure of used powders and final cold sprays. Ultimate tensile strength, yield strength, hardness and plastic elongation are evaluated from the mechanical point of view. Metallographic analysis is focused on particle size in powders and splat size in manufactured layers. Porosity of sprayed layers is evaluated on tested specimens and the influence of specimen dimensions is discussed.

The Influence of Powder Particle Size Distributions on Mechanical Properties of Alloy 718 by Laser Powder Bed Fusion

Currently, metallic powders for laser powder bed fusion (LPBF) primarily come in two commercially available powder size distributions (PSDs): 15+/45− for non-reactive powders and 15+/63− for reactive powders. These powders are generally produced via gas atomization processes that create highly spherical particles with a Gaussian PSD. Because of the standard deviation within a Gaussian distribution, only small portions of the total product are used for LPBF applications. This screening process makes the other particle sizes a waste product and, thus, increases processing costs. The non-reactive 718 powder was printed with both the typical PSD of 15+/45− and a wider bimodal experimental PSD. Compared to conventional 718, the 718 alloys with bimodal PSD shows less than a 0.2% difference in density, and insignificant change in mechanical behavior. Electron backscattered diffraction studies revealed that grain sizes and morphology were similar between the two sample sets, but bimodal 718 alloy has a slightly greater degree of large grains. The study suggests that particles with wide or bimodal size distributions show promise in producing equivalent high-quality products without sacrificing mechanical properties.

Powder Preparation by Vacuum Atomization and 3D Printing Forming Performance of 316 Stainless Steel

This work describes the process of preparing 316 L stainless steel powder by vacuum atomization, then a 3D print sample of 316 L stainless steel is prepared by selective laser melting (SLM) experiments. Over 77% of the powder particle size distribution ranges from 15 to 45 μm. The prepared sample shows a smooth surface with few satellite globules and high sphericity with the 4.5 Mpa atomization pressure. Under these atomization pressure conditions, the tensile strength can reach 798 Mpa and the elongation up to 32.3%. This work demonstrated that 3D printing metal materials with high tensile strength and good plasticity could be obtained under appropriate atomization pressure conditions.

INVESTIGATION OF THE EFFECT OF MESH SIZE AND FRACTION VOLUME ON BENDING STRENGTH CHARACTERISTICS OF GEOPOLYMER COMPOSITE

Composite material is a material consisting of two or more type materials that have different properties, by combining macroscopically, and good interfacial bonds from one material to another. Currently, polymer composite materials are widely applied in the land, sea, and air transportation industries, moreover polymer composites with fire resistance properties have been developed with the addition of geopolymer that has the advantage of producing high performance. This study aims to determine the effect of mesh size and volume fraction of lightweight brick powder on flexural strength. The benefits of this research directly increase the economic value of lightweight brick waste and produce a tough advanced material at a low cost. The composite filling material used lightweight brick waste and sieved using a sieve with a level of 50, 100, 150, and 200 at a volume fraction of 45%, and a volume fraction of 0%, 15%, 30%, 45%, and 60% at a mesh 200. While the composite matrix used the thermoset polymer Ripoxy R-804. Based the result, addition of lightweight brick powder with variations in particle size of the lightweight brick powder and volume fraction showed a decrease in flexural strength resistance compared to those without lightweight brick powder.

The effect of chicken eggshell (Gallus gallus domesticus) particle size as filler to polyester composite as motorcycle’s exhaust pipe cover material

This research was done to know the effect of chicken eggshell (Gallus gallus domesticus) powder particle size on unsaturated polyester resin mechanical properties. The eggshell was mashed and sifted to get the 50 mesh, 70 mesh, 90 mesh, 110 mesh, 130 mesh, 150 mesh, and 170 mesh particle size by using a ball mill. Then, the eggshell was mixed with an unsaturated polyester resin matrix with the ratio of 70:30 and methyl ethyl ketone peroxide (MEKP) catalyst as much as 1 % of the matrix mass. After that, it was pressed by using compression molding. The composite formed was characterized by Scanning Electron Microscopy Energy Dispersive X-ray (SEM EDX), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD). The physical properties of the composite were analyzed and the mechanical properties were tested. The SEM EDX result showed that the eggshell and composite were made up of Ca, C, and O, and the polyester was made up of C, O, and Si. The composite highest tensile strength and impact strength were at 150 mesh particle size of chicken eggshell powder which is 45.153 MPa and 9. 04 J/m2.

Investigating the Microscopic Mechanism of Ultrasonic-Vibration-Assisted-Pressing of WC-Co Powder by Simulation.

The ultrasonic-vibration-assisted pressing process can improve the fluidity and the uneven distribution of density and particle size of WC-Co powder. However, the microscopic mechanism of ultrasonic vibration on the powder remains unclear. In this paper, WC particles with diameter 5 μm and Co particles with diameter 1.2 μm were simulated by three-dimensional spherical models with the aid of the Python secondary development. At the same time, the forming process of the powder at the mesoscale is simulated by virtue of the finite element analysis software ABAQUS. In the simulation process, the vibration amplitude was set to 1, 2, and 3 μm. Their influence on the fluidity, the filling density, and the stress distribution of WC-Co powder when the ultrasonic vibration was applied to the conventional pressing process was investigated. The simulation results show that the ultrasonic vibration amplitude has a great influence on the density of the compact. With an increase in the ultrasonic amplitude, the compact density also increases gradually, and the residual stress in the billet decreases after the compaction. From the experimental results, the size distribution of the billet is more uniform, the elastic after-effect is reduced, the dimensional instability is improved, and the density curves obtained by experimentation and simulation are within a reasonable error range.

Formation mechanism of Fe-based amorphous powders produced by spark erosion

Spark erosion is a convenient, flexible, and low-cost method to quickly produce fine powders of metals, alloys, and semiconductors in size ranging from nearly a hundred micrometers to submicrometer by repetitive spark discharges. Due to the complexity of the powder-forming journey, normally accompanied by high temperature, high pressure, decomposition, diffusion and rapid quenching caused by discharge plasma, the mechanisms of powder formation and possible contaminant infiltration are still controversial, posing a significant challenge to control particle size and chemical composition of the powder produced by this method. In this study, Fe-based amorphous powders in different particle-size distributions with high sphericity were fabricated by spark erosion under different discharge-energy conditions. The maximum particle size of the resultant powders can be correlated with discharge parameters, crater depth, and crater radius, respectively. A multi-ring-breakup model is proposed to reveal the particle-size distribution of the powder formed from the electrode melt under a single-pulse discharge. Furthermore, a dielectric-element infiltration model is provided to quantitatively evaluate the infiltration mass ratio of the contaminant elements, stemming from the decomposed products of dielectric liquid, in the resultant powder with different particle sizes. The models verified through the experimental data are significant for the development of high-performance fine Fe-based amorphous powder with controlled particle size and chemical composition.

Characterization and Optimization of Cu-Al2O3 Nanocomposites Synthesized via High Energy Planetary Milling: A Morphological and Structural Study

This study examines the synthesis and characterization of a copper–alumina nanocomposite powder. Mechanical milling is employed to synthesize the powder, and a holistic analysis is conducted to evaluate its morphological and structural properties. TEM analysis reveals the presence of alumina particles within the copper matrix, indicating the formation of both coarse and fine particles at different stages of synthesis. XRD analysis demonstrates a reduction in copper’s crystallite size with increasing milling time, attributed to defects generated within the crystal lattice during milling. Additionally, statistical analysis is utilized to determine the significance of different factors influencing the synthesis process. ANOVA analysis reveals that milling time has a significant impact on the particle size of the nanocomposite powder, while temperature and their interaction do not exhibit significant effects. Optimization techniques are utilized to identify solutions that meet the specified constraints for milling time, temperature, particle size, and differential thermal response, resulting in favorable solutions within the desired ranges. The study highlights the efficacy of mechanical milling for producing nanocomposite powders with enhanced mechanical properties, offering promising prospects for advanced materials in various industries. Additionally, the characterization results provide valuable insights into the microstructure and phase distribution of the nanocomposite powder. The application of the Williamson–Hall method proves to be effective in determining the crystallite size of the synthesized powder.

Effects of binder droplet size and powder particle size on binder jetting part properties

PurposeIn binder jetting, the interaction between the liquid binder droplets and the powder particles defines the shape of the printed primitives. The purpose of this study is to explore the interaction of the relative size of powder particles and binder droplets and the subsequent effects on macro-scale part properties.Design/methodology/approachThe effects of different particle size distribution (5–25 µm and 15–45 µm) of stainless steel 316 L powders and droplet sizes (10 and 30 pL) on part density, shrinkage, mechanical strength, pore morphology and distribution are investigated. Experimental samples were fabricated in two different layer thicknesses (50 and 100 µm).FindingsWhile 15–45 µm samples demonstrated higher green density (53.10 ± 0.25%) than 5–25 µm samples (50.31 ± 1.06%), higher sintered densities were achieved in 5–25 µm samples (70.60 ± 6.18%) compared to 15–45 µm samples (65.23 ± 3.24%). Samples of 5–25 µm also demonstrated superior ultimate tensile strength (94.66 ± 25.92 MPa) compared to 15–45 µm samples (39.34 ± 7.33 MPa). Droplet size effects were found to be negligible on both green and sintered densities; however, specimens printed with 10-pL droplets had higher ultimate tensile strength (79.70 ± 42.31 MPa) compared to those made from 30-pL droplets (54.29 ± 23.35 MPa).Originality/valueTo the best of the authors’ knowledge, this paper details the first report of the combined effects of different particle size distribution with different binder droplet sizes on the part macro-scale properties. The results can inform appropriate process parameters to achieve desired final part properties.

State of the Art on Waste Glass Powder as Supplementary Cementitious Material

As a new type of high-performance concrete material, glass powder (GP) concrete is beneficial to the environment and concrete performance. However, the specific application method still needs to be studied. This paper introduces the structure theory of glass and the mechanism by which glass powder affects concrete. Through experiments, the effects of glass powder particle size, content, alkali content, and other factors on alkali-silica reaction (ASR) expansion, mechanical properties, and durability of concrete are compared. It is proven that glass powder can be used as a gel material in concrete. The existing problems in the research are summarized, and the latest research perspectives and methods are suggested.

Microstructure and reduction behavior of Mo powders doped with La2O3 and ZrO2 oxides using the spray drying method

In the present contribution, we used the spray drying method for the preparation of molybdenum-based composite powders, which belong to an important class of high-temperature structural materials – oxide dispersion strengthened molybdenum alloys (ODS-Mo). Three types of materials were prepared via spray drying and subsequent steps of calcination and reduction, including undoped reference Mo, ODS-Mo doped with 1 wt% of La2O3, and ODS-Mo doped with 1 wt% of La2O3 and 1 wt% of ZrO2. The particular focus was given to precursor solution; specifically, the effects of type (aqueous or water-ethanol mixture) and chemical composition (the addition of La and Zr precursors) were studied in detail, which was rarely given attention in previous research. The morphological and microstructural changes of the particles during oxidation and reduction of sprayed-dried powders were extensively analysed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The morphology and crystallinity of spray dried powders were controlled by the state of spraying precursor solution, i.e. homogeneous solution or particle suspension. Calcination at the temperatures of 500 °C and 650 °C produced spherical polycrystalline and slab-shaped monocrystalline MoO3 oxide particles. Subsequent reductive treatment of transformed calcined powders into metal-based powders took place with efficiency that depended mainly on the type of spraying solution (aqueous solution or water-ethanol suspension) and its chemical composition, in which case, the addition of La and Zr precursors resulted in lower efficiency than the addition of La alone. In terms of powder particle size, homogeneity of alloying elements, and reduction efficiency, the powders produced from water-ethanol suspensions were clearly superior to those produced from aqueous solutions.

About the assessment of sampling error and representative sample in X-ray fluorescence analysis of mineral powders

The assessment of laboratory sampling errors in X-ray fluorescence analysis (XRF) of mineral powders ground to a particle size less than 75 μm is important when analyzing specimen portions less than 100–300 mg. The sampling error can be found from Poisson statistics, which allows one to estimate the variations in the number of mineral grains containing an analyte in a powder sample of a fixed mass. However, the absorption of X-ray radiation in the sample imposes a limitation on the analyzed mass due to the low penetration depth of X-rays, especially in the energy region below 4 keV.In this paper, we propose the sampling error estimation based on Poisson statistics taking into account the size of powder particles in comparison with the penetration depth of X-rays. Two limiting cases are considered, when the penetration depth is greater or less than the size of the grains containing the analyte. Zircon, ilmenite, and quartz were considered as grains containing the analyte, and boric acid and clay were taken as matrices. Measurements were carried out with wavelength dispersive XRF spectrometer. It was shown that the sampling errors obtained experimentally for different model mixtures are close to the sampling errors calculated using Poisson statistics. The described model of quartz inclusions in clay matrix was used to explain the relatively low sampling error in determining the main components Al2O3, SiO2, K2O in course-grain Neolithic ceramics.

Study on Preparation of Homogenized Highly Dispersible AlON Powder

The quality of Aluminum oxynitride (AlON) powder is the main factor affecting the properties of ceramics. To accurately control the nitrogen AlON content and improve the dispersion degree of powder, AlON powder was prepared from γ-Al2O3 and activated carbon powder by carbothermic reduction and nitridation. The uniformity of distribution of raw materials and the dimension and microstructure of AlON powder was controlled by changing the time and rotation rate of the ball milling process. The influences of ball milling process parameters on the microstructure and distribution uniformity of Al2O3/C mixed powder, microstructure, and particle size of AlON powder were studied. The results show that powder agglomeration was effectively reduced, and the uniformity of raw material distribution was increased by controlling the time and rotation rate of the ball milling process. The Al2O3/C mixed powder has good particle size and uniform distribution with roller ball milling for 24 h. After holding the powder at 1700 °C for 60 min, the homogenized AlON powder was obtained, and the residual carbon content was about 0.04 wt%. When the time of planetary ball milling at 250 rpm was 16 h, highly dispersible AlON powder was obtained.

Effect of MoO3 and TiO2 Powder Particle Sizes on the Phase Composition and Density of Dysprosium Titanate Pellets

Effect of MoO3 and TiO2 Powder Particle Sizes on the Phase Composition and Density of Dysprosium Titanate Pellets

The characteristic and sensory evaluation of arabica Semendo coffee in high-speed stirring cold brew and common brew

Differences in brewing methods both from extraction time and brewing water temperature can affect the number of chemical compounds dissolved. This study applied the cold brew brewing method with high-speed stirring to Arabica Semendo coffee with extraction times of 15, 30, and 45 minutes at different particle sizes of coffee powder (coarse, medium, and fine) to obtain coffee with better characteristics than the commonly used brewing methods (hot brew and cold brew) and acceptable in sensory evaluation. The pH, viscosity, total soluble solids, total microbes, and sensory evaluation by hedonic tests on taste, color, and aroma were investigated. Coffee with high-speed stirred cold brewing for more than 30 minutes with finer coffee grounds had higher pH, viscosity, and total soluble solids than common brewing as a control. The size of the coffee grounds and the difference in brewing method did not affect microbial contamination. The results of the hedonic test on color, taste, and aroma in the cold brewing method of high-speed stirring produced coffee that was accepted by consumers and was not significantly different from the common brew.

Producing Metal Powder from Machining Chips Using Ball Milling Process: A Review.

In the pursuit of achieving zero emissions, exploring the concept of recycling metal waste from industries and workshops (i.e., waste-free) is essential. This is because metal recycling not only helps conserve natural resources but also requires less energy as compared to the production of new products from virgin raw materials. The use of metal scrap in rapid tooling (RT) for injection molding is an interesting and viable approach. Recycling methods enable the recovery of valuable metal powders from various sources, such as electronic, industrial, and automobile scrap. Mechanical alloying is a potential opportunity for sustainable powder production as it has the capability to convert various starting materials with different initial sizes into powder particles through the ball milling process. Nevertheless, parameter factors, such as the type of ball milling, ball-to-powder ratio (BPR), rotation speed, grinding period, size and shape of the milling media, and process control agent (PCA), can influence the quality and characteristics of the metal powders produced. Despite potential drawbacks and environmental impacts, this process can still be a valuable method for recycling metals into powders. Further research is required to optimize the process. Furthermore, ball milling has been widely used in various industries, including recycling and metal mold production, to improve product properties in an environmentally friendly way. This review found that ball milling is the best tool for reducing the particle size of recycled metal chips and creating new metal powders to enhance mechanical properties and novelty for mold additive manufacturing (MAM) applications. Therefore, it is necessary to conduct further research on various parameters associated with ball milling to optimize the process of converting recycled copper chips into powder. This research will assist in attaining the highest level of efficiency and effectiveness in particle size reduction and powder quality. Lastly, this review also presents potential avenues for future research by exploring the application of RT in the ball milling technique.

Fabrication of highly ordered willemite/PCL bone scaffolds by 3D printing: Nanostructure effects on compressive strength and in vitro behavior

In this study, first willemite (Zn2SiO4) micro and nano-powders were synthesized by the sol-gel method. X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS) were applied to characterize the crystalline phases and particle size of powders. Then polycaprolactone (PCL) polymer scaffolds containing 20 wt% willemite were successfully fabricated by the DIW 3D printing (direct ink writing) method. The effects of willemite particle size on compressive strength, elastic modulus, degradation rate, and bioactivity of the composite scaffolds were investigated. The results showed that nanoparticle willemite/PCL (NW/PCL) scaffolds had 33.1% and 58.1% higher compressive strength and the elastic modulus of NW/PCL were 1.14 and 2.45 times better compared to micron size willemite/PCL (MW/PCL) and pure PCL scaffolds, respectively. Scanning electron microscopy (SEM) images and Energy-dispersive X-ray spectroscopy map (EDS map) results indicated that willemite nanoparticles, unlike microparticles, were smoothly embedded in the scaffold struts. In vitro tests also revealed an improvement in bone-like apatite formation ability and an increase in the degradation rate up to 2.17% by decreasing the willemite particle size to 50 nm. In addition, NW/PCL rendered significant enhancement in cell viability and cell attachment during the culture of MG-63 human osteosarcoma cell line. Nanostructure had also a positive effect on ALP activity and biomineralization in vitro.

Suppression method of industrial Al alloy powder explosion in dry and humid environment: A low-cost intrinsic safety technology

During the production and processing of Al alloy, a large number of small particle size powders will be produced. If the concentration of these Al alloy dust is too high under dry conditions, it will lead to dry powder explosion, and if hydrogen is produced in contact with water under wet conditions, it will lead to hydrogen explosion. This work is intended to develop a simple, cost effective technology that inerts waste Al alloy dust and minimizes its explosion hazards in different environments. Dihydrogen phosphates (KH2PO4, NH4H2PO4, Ca(H2PO4)2) are used to test the explosion flame propagation, explosion pressure, and hydrogen evolution, of waste Al alloy dust. The results show that dihydrogen phosphate can significantly reduce the flame propagation distance, speed, explosion pressure and hydrogen evolution performance of Al alloy dust, and inhibit the explosion of Al alloy dust in dry and humid environment to varying degrees. In different experiments, Ca(H2PO4)2 has the best inerting effect, low cost and simple operation, which realizes the intrinsic safety of metal dust processing process. The phosphating film on the surface of Al alloy particles blocks the generation of Al(OH)3 and retains the metal body to the greatest extent, which provides a possibility for the recycling of waste metal dust.

Effects of expanded graphite content on the performance of MgO‐C refractories

AbstractExpanded graphite was introduced into a MgO‐C refractory to suppress its thermal expansion and thus enhance thermal shock resistance. The refractory was prepared by mixing MgO powders (particle size = 75 μm and 1 mm), antioxidant and curing agents, flake and expanded graphite, and a novolak‐type phenolic resin at 50°C. This was followed by aging at 20°C for 24 h, compacting by uniaxial pressing, curing at 210°C for 5 h, and heat treatment at 1500°C. With an increase in expanded graphite content from 0 to 4 wt.%, the bulk density decreased, apparent density remained unchanged, and apparent porosity increased. The gaps created in the vicinity of MgO particles because of this increase in apparent porosity buffered the thermal expansion of MgO. This increased resistance to thermal shock up to 1500°C. However, the increase in expanded graphite content also had a detrimental effect reflected in the decrease in fracture strength and increase in the residual strain after repeated thermal shock. This contradiction indicates that composition optimization is important for the practical performance enhancement of MgO‐C bricks. The optimum content of the expanded graphite was determined as 2 wt.%.