Properties Of Powders Research Articles

Synthesis and Characterization of (Ni,Co)xMn0.25-xMg0.75Fe2O4 Nanoparticles

Ni-Co-Mn-Mg ferrite nanoparticles with the formula (Ni,Co)xMn0.25-xMg0.75Fe2O4 were synthesized in this work by employing the sol-gel auto-combustion process, with nitrates used as the cations source and citric acid (C6H8O7) as the combustion agent. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), and a vibrating sample magnetometer (VSM) were used to characterize the structural, morphological, and magnetic properties of ferrite powders. The XRD measurements showed crystallite sizes ranging between 24 - 28 nm. The FE-SEM images show the presence of agglomeration as well as a non-homogeneous distribution of the samples. On the other hand, the stoichiometry of the reactant solutions that were used is in close agreement with the elemental analysis that was obtained from EDX showing that the composition was as expected. Manganese ferrite showed a decrease in magnetic parameters on magnesium doping, which was further enhanced in (Ni,Co)xMn0.25-xMg0.75Fe2O4 nanoparticles upon replacement of nonmagnetic manganese ions for nickel and cobalt ions. Results indicated that Ni-Co-Mn-Mg ferrite nanoparticles’ crystal morphology, structural, and magnetic properties were significantly influenced by the amounts of nickel and cobalt content.

Microstructure development of plasma sprayed dual-phase high entropy ceramic coating derived from spray dried and induction plasma spheroidized powder

Dual phase high entropy ceramics (DPHECs) exhibit excellent high temperature mechanical properties and oxidation resistance. Nevertheless, they cannot be applied in the structural components on large scale due to their intrinsic brittleness. Hence, DPHEC coating is a necessary development direction for industrial applications. In this study, we first fabricated micron-order DPHEC powder with high quality by precursor synthesis, spray drying (SD), and induction plasma spheroidization (IPS). The DPHEC coating was prepared by supersonic atmospheric plasma spraying (SAPS). The microstructure, phase compositions, and mechanical properties of the DPHEC powder and coating are investigated in detail. Results show that the SD&IPS powder and SAPS coating are all composed of HEB and HEC phases, showing slight composition segregation and typical global eutectic microstructure. The nanohardness and Young's modulus are 22.17 ± 2.76 GPa and 309.79 ± 35.71 GPa, respectively. The fracture toughness was calculated to be 2.23 ± 0.17 MPa m1/2 from the energy analysis method. The mechanical properties are enhanced by the solid solution and fine grain strengthening effects and are weakened by the intrinsic defects of plasma sprayed coating. This work provides a new method and a potential material for thermal spraying ultra-high temperature ceramic coatings.

The Effect of Drying Time on the Antioxidant Properties of Single Black Garlic Powder

Black garlic is a processed product derived from fresh garlic that generally has a taste and aroma that is less preferred. A drying process is employed to increase the attractiveness of consuming black garlic. This study aims to assess the impact of the drying time on the antioxidant activity and content of antioxidant compounds such as phenolics, flavonoids, and tannins in single black garlic. The drying time is expected to yield a single black garlic powder that is more convenient for consumption, whether in capsule form or as an addition to food products. With low moisture content, single black garlic powder has a longer shelf life and high antioxidant activity, potentially commanding a higher market value. In this research, the drying time was carried out on a single black garlic using an oven for 6, 12, 18, and 24 hours. The analysis of the total phenolic content (TPC), entire tannin content (TTC), and total flavonoid content (TFC) was determined using a Uv-Vis spectrophotometer, and each component was measured concerning gallic acid equivalent for TPC, quercetin for TFC, and tannic acid for TTC. Antioxidant activity was determined using the DPPH method, and the outcomes were expressed as IC50 values. The research shows that the extended drying time leads to an augmentation of the antioxidant compound in black garlic. Drying for 24 hours produces significant outcomes, showing potent antioxidant activity with an IC50 value of 37,019 ppm (powerful antioxidant category), total phenolic content value is 44,785 ± 0,033 mgGAE/g, total flavonoid content value is 32,033 ± 0,008 mgQE/g, and total tannins content value is 74,884 ± 0,057 mgTAE/g. Statistical analysis using a one-way ANOVA showed a significant influence of drying time on TPC, TFC, and TTC (p < 0,05). The longer the drying time, the higher the antioxidant activity and the content of compounds acting as antioxidants in black garlic powder.

Effects of nano-metal oxide additives on ignition and combustion properties of MICs-boron rich fuels

Boron has been considered a promising powdered metal fuel for enhancing composite propellants' energy output due to its high energy density. However, the high ignition temperature and low combustion efficiency limit the application of boron powder due to the high boiling point of the boron oxide layer. Much research is ongoing to overcome these shortcomings, and one potential approach is to introduce a small quantity of metal oxide additives to promote the reaction of boron. This study prepared boron-rich fuels with 10 wt% of eight nano-metal oxide additives by mechanical ball milling. The effect of metal oxides on the thermo-oxidation, ignition, and combustion properties of boron powder was comprehensively studied by the thermogravimetric analysis (TG), the electrically heated filament setup (T-jump), and the laser-induced combustion experiments. TG experiments at 5 K/min found that Bi2O3, MoO3, TiO2, Fe2O3, and CuO can promote thermo-oxidation of boron. Compared to pure boron, Tonset can be reduced from 569 °C to a minimum of 449 °C (B/Bi2O3). Infrared temperature measurement in T-jump tests showed that when heated by an electric heating wire at rates from 1000 K/s to 25000 K/s, the ignition temperatures of B/Bi2O3 are the lowest, even lower than the melting point of boron oxide. Ignition images and SEM for the products further showed that the high heating rate is beneficial to the rapid reaction of boron powder in the single-particle combustion state. Fuels (B/Bi2O3, B/MoO3, and B/CuO) were mixed with the oxidant AP and ignited by laser to study the combustion performance. The results showed that B/CuO/AP has the largest flame area, the highest BO2 characteristic spectral intensity, and the largest burn rate for powder lines. To combine the advantages of CuO and Bi2O3, binary metal oxide (CBO, mass ratio of 3:1) was prepared and the test results showed that CBO can very well improve both ignition and combustion properties of boron. Especially B/CBO/AP has the highest burn rate compared with all fuels containing other additives. It was found that multi-component metal-oxide additive can more synergistically improve the reaction characteristics of boron powder than unary additive. These findings contribute to the development of boron-rich fuels and their application in propellants.

Microstructures and properties of Al2O3 dispersion-strengthened Cu10Sn oil bearings prepared by solid-liquid doping and reactive synthesis method

To modify the shortcomings of Cu10Sn oil bearing in mechanical performance, this work proposes to prepare the Al2O3 oxide dispersion strengthened (ODS) Cu10Sn oil bearings by reactive synthesis using elemental Sn and Al2O3 ODS-Cu powder, among which the uniformly doped Al2O3 ODS-Cu powder was synthesized through a solid-liquid doping of Al(NO3)3 in CuO powders followed with hydrogen reduction. The effects of Al2O3 content on the microstructure and properties of ODS-Cu powder and ODS-Cu10Sn oil bearings were investigated in details. The results showed that an increase in Al2O3 amount from 0 to 1.5 wt% leads to a decrease in the average particle size of the reduced ODS-Cu powders, and contributes to the significant improvement of radial compressive strength, and Vickers microhardness. The appropriate sintering temperature is approximately 800 °C, which can result in the evenly distributed Al2O3 and well-developed porosity in oil bearing sample after sintering. The corresponding compressive strength and microhardness of ODS1.5-Cu10Sn oil bearing can reach 305 MPa and 208 HV respectively.

Encapsulation of anthocyanin from butterfly pea flowers (Clitoria ternatea L.) extract using foam-mat drying

Butterfly pea flower (BPF) is a rich source of anthocyanin, a natural phytonutrient widely used in food and pharmaceutical applications. However, the stability of anthocyanin limits its utilization. This study encapsulates anthocyanin extracted from dried BPF using monoglycerides (MG) as foaming agents and maltodextrin (MD) as stabilizers in foam-mat drying. MG concentrations of 2.5%, 3.5%, and 5.0% and MD content at 10%, 15%, and 20% were conducted at drying temperatures of 60°C, 70°C, and 80°C. According to the findings, increasing MG content promoted foam porosity, reducing drying times. Meanwhile, higher MD amounts improved foam stability and anthocyanin retention in dried particles. Using 3.5% MG and 20% MD at 70°C, up to 210 mg/100 g of anthocyanin was retained, with 98% encapsulation efficiency. The presence of MG could inhibit the activity of Bacillus subtilis. The overall properties of BPF powder were comparable to those of commercial products. As a result, this research could help guide the use of MG in combination with MD in foam-mat drying as an alternative method in the food drying industry.

Effects of Induction Plasma Spheroidization on Properties of Yttria-Stabilized Zirconia Powders for Thermal Barrier Coating Applications.

In this study, the induction plasma spheroidization (IPS) technique was adopted to improve the microstructure and properties of the traditional agglomerated ZrO2-7wt%Y2O3 (YSZ) powders used in thermal barrier coating (TBC) applications. Compared with agglomerated YSZ powders, IPS-treated powder has a more desirable microstructure, and the overall performance of the spray powders for TBC preparation is significantly improved. Specifically, IPS-treated powder has a dense, solid, defect-free, and chemically uniform microstructure, and its apparent density, flowability, and powder strength are significantly improved, which is believed to substantially enhance the coating performance when prepared with this IPS-treated powder.

Reuse of Smoulder in Laser Powder-Bed Fusion of AlSi10Mg—Powder Characterization and Sample Analysis

Metal additive manufacturing technologies, such as Laser Powder-Bed Fusion, often rate as sustainable due to their high material efficiency. However, there are several drawbacks that reduce the overall sustainability and offer potential for improvement. One such drawback is waste emerging from the process. These smoulder particles form when the laser hits the powder-bed surface, are blown away from the part by the shielding gas stream and accumulate on the edge of the build chamber. Usually, smoulder does not contribute to the circular reuse of powder that was part of the powder-bed but was not integrated into a part. Instead, it marks an end-of-life state of powder. Significant amounts of smoulder accumulate depending on the irradiated area or the build volume in one job, respectively. This results in the waste of powder that was produced with low energy efficiency. This study investigates the question of whether smoulder can transform from waste to resource via common powder characterization methods and first build jobs using processed smoulder. The investigation of process-relevant powder properties like apparent density and flowability showed no significant difference between virgin powder and smoulder. Sample characterization indicated that neither porosity, surface quality nor mechanical properties deteriorate when samples contain about 50% smoulder. This allows for the reuse of smoulder in terms of powder characterization and part quality.

Carboxymethyl cellulose aerogel decorated MOF-808 with defects via mixed-metallic center and etching for enhanced Pb(II) removal

Pb(II) removal from water is essential for human health due to their high toxicity and carcinogenicity. Metal-organic frameworks (MOFs) have potential to remove heavy metal ions because of their adjustable structure and tunable pore size. However, the microporous structure limits their removal performance because Pb(II) mainly exists in water as hydrated ion, which is larger than the pore size of MOFs. Defect engineering is promising to form suitable pore to capture Pb(II). Herein, we developed an etched Cu0.3Zr0.7-MOF-808 MOF by a mixed-metal strategy followed with an etching process. We replaced part of Zr4+ in the MOF-808 skeleton with Cu2+ through competition between Zr4+/Cu2+ for coordinating with –COOH on 1,3,5-Benzenetricarboxylic acid (H3BTC) to increase its specific surface area. Then H3PO4 and EDTANa2·2H2O as etchants were used to break the coordinate bond between Zr4+/Cu2+ and –COOH on H3BTC to achieve macroporous structure to inhabit Pb(II). The powder property of MOFs limits their practical applications due to their poor recyclability. We crosslinked the MOF on CMC by coordinating Zr4+ on the MOF with –COOH on CMC to form aerogel to facilitate its recyclability. The maximum adsorption capacity for Pb(II) was 542.77 mg/g at 45 °C. The adsorption of Pb(II) conformed to the intra-particle diffusion model and the Langmuir model, illustrating that the adsorption process was monolayer adsorption and affected by intra-particle diffusion. The electrostatic attraction and chelation between Pb(II) and –COOH accounted for the effective Pb(II) removal performance. This work provides a novel idea for the removal of heavy metal ions from water.

Mechanism of enhancing rehydration capacity and foaming property of spray-dried egg white powder by lactic acid fermentation

Spray-dried egg white powder has limited applicability as a raw material in food production due to its deteriorative rehydration capacity. Lactic acid fermentation is a promising technique for protein denaturation and has been widely used in the food industry. In this work, we investigated the effects of 4, 8, and 12-h lactic acid fermentation on protein structure, powder characteristics, rehydration capacity, and foaming property of spray-dried egg white powder. Results show that the fermentation treatment significantly reduced the surface hydrophobicity of egg white powder samples, while 8 and 12 h of fermentation significantly increased their zeta potential. During the 12 h of fermentation, the particle size of the powder gradually decreased from 2.59 μm to 1.69, 1.23, and 0.76 μm, respectively. Scanning electron microscope result shows the same and also indicates a concave hole structure in fermented egg white powders. These changes in protein molecules result in the significantly improved wettability, dispersibility, and solubility of the powder, thus enhancing its rehydration capacity. The foaming ability and foam stability of egg white powder also significantly improved after fermentation. Furthermore, the fermentation process altered the secondary structure, moisture content, bulk densities, flowability, and color of the powder. This work demonstrates the usefulness of lactic acid fermentation in enhancing the quality of egg white powder. The findings have significant implications for the development of better-quality egg white powder products in the food industry.

Investigating the Effects of Mixing Dynamics on Twin-Screw Granule Quality Attributes via the Development of a Physics-Based Process Map.

Twin-screw granulation (TSG) is an emerging continuous wet granulation technique that has not been widely applied in the industry due to a poor mechanistic understanding of the process. This study focuses on improving this mechanistic understanding by analyzing the effects of the mixing dynamics on the granule quality attributes (PSD, content uniformity, and microstructure). Mixing is an important dynamic process that simultaneously occurs along with the granulation rate mechanisms during the wet granulation process. An improved mechanistic understanding was achieved by identifying and quantifying the physically relevant intermediate parameters that affect the mixing dynamics in TSG, and then their effects on the granule attributes were analyzed by investigating their effects on the granulation rate mechanisms. The fill level, granule liquid saturation, extent of nucleation, and powder wettability were found to be the key physically relevant intermediate parameters that affect the mixing inside the twin-screw granulator. An improved geometrical model for the fill level was developed and validated against existing experimental data. Finally, a process map was developed to depict the effects of mixing on the temporal and spatial evolution of the materials inside the twin-screw granulator. This process map illustrates the mechanism of nucleation and the growth of the granules based on the fundamental material properties of the primary powders (solubility and wettability), liquid binders (viscosity), and mixing dynamics present in the system. Furthermore, it was shown that the process map can be used to predict the granule product quality based on the granule growth mechanism.

Chiral fluorescent liquid crystal polymers containing 4-bromo-1,8-naphthalimide – synthesis and properties

ABSTRACT By introducing two cholesteric liquid crystal monomers with different chain lengths (M1 and M2) and brominated naphthalimide fluorescent monomer (M3) into polymethyl hydrosiloxane, a series of fluorescent cholesteric liquid crystal polymers (FL-LCP) was prepared, which not only have excellent performance of liquid crystal and fluorescence but also own performance of selective reflection. Their chemical structures were confirmed to be in accord with molecular design by FT-IR and 1 H NMR spectroscopy, and found them with excellent thermal stability, mesomorphic behaviour and thermal performance by TGA, POM, DSC and XRD, and confirmed all the polymers belonged to the cholesteric phase. The FL-CLCPs emitted different intensity fluorescence under UV light, and conclusions about the relationship between fluorescence and temperature had been drawn. A comparative study was conducted on the fluorescence properties of powders and films of monomers and polymers.

Review on preparation technology and properties of spherical powders

Review on preparation technology and properties of spherical powders

Effect of bimodal size distribution on the behavioural properties of powders used in the LPBF process

The adoption of the Laser Powder Bed Fusion (LPBF) process faces challenges due to a low productivity and high powder costs. Improvements in productivity can be achieved by increasing the laser power and the layer thickness. The present work explores an alternative approach by investigating the use of coarser particle size distributions in conjunction with thick powder layers. This approach potentially allows the valorisation of currently unexploited powder fractions in the LPBF process. In this work, blends of AISI 420 stainless steel powders are characterised in terms of their compaction dynamics and flow properties. The results obtained show that different levels of cohesion and compaction rate are found depending on the size ratio, the absolute size of the fine powder and its fraction. This work provides guidance for the selection of powder blends and opens up the possibility of their use in the LPBF process.

Characterization of mechanochemical modification in SiC powder

In this study, SiC powder was prepared via a mechanochemical method utilizing high-energy ball milling. The SiC powder, subjected to varying milling durations, was analyzed using X-ray diffraction, Masterizer2000, and scanning electron microscopy. The results indicate that SiC powder achieves a uniform distribution of particle size after 5 min of ball milling, resulting in smaller particle diameters and a larger specific surface area. Concurrently, it exhibits high solid activity and enhanced purity. This suggests that a brief period of ball milling is sufficient to significantly improve the physical properties of SiC powder, which is crucial for applications requiring high material purity and reactive surface area.

Analyzing the Characteristics of Fishbone Powder Derived from Pangasius sp., Thunnus tonggol, and Thunnus albacares as Food Fortificant

Pangasius sp., Thunnus tonggol (T. tonggol), and Thunnus albacares (T. albacares) are high-value commercial species widely used in fillet production, generating by-products, such as fishbone. The fishbone, rich in calcium (CA) and phosphorus (P), offers a valuable alternative for daily Ca intake. Using such by-products as a potential source of Ca presents a viable solution, offering food-fortificant ingredients applicable in various food products. Therefore, this study examined the physical and chemical properties of fishbone powder derived from Pangasius sp., T. tonggol, and T. albacares. The products preparations were subjected to cooking, autoclaving, pulverization, homogenization, drying, and grinding. The physical and chemical analysis of fishbone powder showed that T. tonggol and T. albacares had a darker color compared to Pangasius sp., with higher protein content and likely stimulation of a Maillard reaction during the drying process. All species maintained a neutral pH range, and their particle sizes significantly differed (p< 0.05), ranging from nm to µm. SEM images showed irregularly shaped and agglomerated particles in all fish species. The ash content was 54.35 g/100 g (Pangasius sp.), 53.62 g/100 g (T. tonggol), and 52.28 g/100 g (T. albacares), showing high mineral content, particularly in Ca exceeding 40%. The analysis of a Fourier transform infrared spectroscopy (FT-IR) showed carbonate and phosphate peaks, representing the presence of calcium salts. Based on the evaluation, fishbone powder for each species had the potential to serve as food fortificant.

Effects of different preparation methods on the physical, chemical and functional properties of protein powders from Skipjack tuna (Katsuwonus pelamis) liver

Tuna livers (TL), which are often discarded as waste, are a valuable source of protein for human consumption. However, the preparation method used affects the nutritional and functional characteristics of protein powders. This work aimed to investigate the effects of different preparation methods on the physical, chemical, and functional properties of tuna liver protein powders (TLPPs) following heat (H) treatment, heat and ultrasound-assisted (HU) extraction, alkaline pH shift (APS) process, and supercritical carbon dioxide fluid (SC-CO2 ) extraction. H at 85°C (H85), HU at 80 kHz and 100 W (HU-80-100), APS at pH 11.5 (APS 11.5), and SC-CO2 at 350 bars (SC-CO2 -350) resulted in the remarkably highest total protein content among the different preparation conditions. All TLPPs, except for APS 11.5, showed lighter color characteristics. The most abundant amino acids in all TLPPs were glutamic acid, aspartic acid and alanine. The protein solubility and foaming capacity were efficiently improved by SC-CO2-350. Nevertheless, the emulsion properties and oil holding capacity were greatly enhanced by H85 and HU-80-100, and a significant foaming stability and water holding capacity were found in APS 11.5. Therefore, the TLPPs obtained following different preparation methods are unique and could be potentially utilized as a source of protein ingredients in several food systems.

Modification and characterization of tricalcium silicate bio-ceramic powders synthesized by sol-gel process for potential application in dental treatment

Tricalcium silicate powders (Ca3SiO5 or C3S) were fabricated by sol-gel process from the initial materials of Ca(NO3)2·4 H2O and Si(OC2H5)4 (TEOS) in acid medium. Effects of stoichiometry of reagent and catalyst, and temperature on physical-chemical, mechanical, and biological properties of C3S powders were examined systematically. The radiopacity, setting time, compressive strength, and bioactivity were investigated according to ISO recommendations. The radiopacity was compared and evaluated using dopants. The setting time and compressive strength were determined using water solvent. Analysis of bioactivity, antibacterial activity, and biocompatibility of Ca3SiO5 powders was performed and evaluated using simulated body fluid (SBF), and Tetrazolium (WST-1) reagent assay on Escherichia coli bacterium (E. coli), respectively. The milled-C3S powders showed a fine radiopacity with ZrO2 dopant, a shorter setting time, a higher density and a feasible compressive strength. The high purity of the milled-C3S powders with presence of Ca and Si compositions was confirmed by SEM-EDS analysis. Also, hydroxyapatite (HAp) was induced to form on the surface of milled-C3S powders when immersed in SBF. The surface compositional, morphological and chemical structural changes of the milled-C3S powders before and after immersing were analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results showed that a dense HAp layer was formed after 7 days of immersing. It indicated that C3S powders were bioactive and might be used for preparation of dental biomaterials. The milled-C3S powders also showed a potential antibacterial activity on the E.Coli cells and a high biocompatibility for cell viability. The good physical and excellent mechanical properties, bioactivity, and antibacterial activity confirmed the milled-Ca3SiO5 powders as a promising dental filling material.

Unchannelized granular flows: Effect of initial granular column geometry on fluid dynamics

In recent years, significant progress has been made in modelling granular flows using the μI-rheology model, which connects the viscosity of a granular medium to the pressure and strain rate via a dimensionless quantity called the inertial number, I. This model allows treating the granular material as a non-Newtonian liquid with a yield stress, making it possible to model the flow using the continuum approach, which is less computationally expensive than discrete element methods.In this paper, we implement the μI-rheology model in a computational fluid dynamics (CFD) code and couple it with the volume of fluid (VOF) interface tracking approach to model the three-dimensional (3D) flow of monodisperse granular materials. After validating the model using experimental data, we briefly describe a trial-and-error method for evaluating the material properties of powders via a simple collapse experiment. Then, employing the CFD model, we investigate the physics of the unchannelized collapse of granular materials and perform an energy budget analysis to demonstrate the different stages of the granular collapse.To further investigate the effect of the initial shape of the pile on the spreading dynamics, we run a campaign of 3D simulations. Our results show that the μI-rheology model accurately reproduces the dynamics of the granular material during the collapse and can be used for risk assessment purposes in natural disasters. The findings from our simulations can also aid in developing preventative measures to minimize potential harm.

Insights into the assessment of spreadability of stainless steel powders in additive manufacturing

This work investigates the link between the single particle and bulk flow properties of stainless steel (SS316L) powders and their spreading behaviour for additive manufacturing (AM) application. Two different batches of SS316L powders, noted to have significantly different spreading behaviour in AM machines, were investigated. The two batches had almost identical particle size, morphology and bulk flow properties as quantified by angle of repose, Hausner ratio, Carr index and basic flow energy; however one of the batches did not consistently flow during Hall and Carney flow tests and also had very poor spreadability when evaluated using an in-house spreading rig. The flow and spreading behaviours of the poorly spreading batch significantly improved and became almost identical to the good batch when tested following drying, either in a vacuum oven or a freeze dryer. Elemental analysis revealed that batches had some small but significant differences in chemical composition. This study revealed the complexity of defining a correlation between powder properties and spreading behaviour, and the importance of considering the environmental conditions.