Preparation Of Powders Research Articles

Effect of Powder Preparation of FeNiCoCrMo0.5Al1.3 High-Entropy Alloy on the Phase Composition and Properties of High-Velocity Oxy-Fuel-Sprayed Coatings

In this work, the effect of high-entropy alloy powder preparation on the coatings deposited via high-velocity oxygen fuel sprayings was studied. The powders of FeNiCoCrMo0.5Al1.3 composition were prepared by milling and gas atomization. The structures, porosity, phase composition, and microhardness of the coatings produced from mechanically alloyed and gas-atomized powders were compared. The influence of milling parameters on the powder phase composition and morphology was studied. Milling at 600 rpm for 1.5 h allowed the production of mechanically alloyed powder with a homogeneous distribution of Fe, Ni, and Al and thin lamellas enriched with Co, Cr, and Mo. Despite the difference in the feedstock powders’ phase compositions, the phase compositions of the coatings deposited from mechanically alloyed and gas-atomized powders are the same consisting of BCC, FCC solutions, and oxide. The amount of FCC solutions and oxide in the coating depends on the size distribution of the sprayed powder. It was found that the phase composition and the properties of the coatings deposited from the mechanically alloyed and gas-atomized powders of similar sizes are similar.

In-situ preparation of WC-Co composite powders

WC-6Co and WC-10Co composite powders with uniform distribution of Co phase were successfully prepared using WO3, Co2O3 and carbon black as raw materials by the process of “carbothermal pre-reduction + solid phase carbonization”. The phase evolution as well as the influences of carburizing time and temperature on the morphology and particle size of products were investigated. The results showed that there were two reduction paths for WO3. In one case, the reduction of WO3 was completed in the order of WO3 → W18O49 → WO2 → W and W2C. The other was that WO3 first reacted with Co3O4 to form CoWO4, and then CoWO4 was directly reduced to W and W2C. Combined with the thermodynamic calculation and XRD results, W and W2C preferentially transformed into low-carbon η phase (Co3W9C4 and Co2W4C) rather than WC phase. Subsequently, Co3W9C4 and Co2W4C were transformed into Co3W3C. Finally, the Co3W3C phase was further carbonized to form WC and Co phases. Moreover, the increase of Co content promoted the reduction and carbonization reactions. The morphology and particle size had little change with the extension of carburizing time. However, as the carburizing temperature rose, the particle size of WC increased obviously, and there was a serious agglomeration.

Preparation of whole-wheat instant powder from dehulled wheat by ethanolic extrusion

This study investigated the efficacy of ethanolic extrusion in producing whole-wheat instant powder that dissolves and pastes well in both cold and hot water, using dehulled wheat kernel as the raw material. Varying ethanol concentrations, extrusion temperatures, and screw speeds were explored through single-factor experiments and an orthogonal test for process optimization. Optimal parameters of an extrusion temperature of 125 °C, a screw speed of 90 rpm, and an ethanol content of 9.35% were identified. Under these conditions, the whole-wheat instant powder exhibited superior dispersibility, forming a creamy consistency in cold water with a viscosity of 1472 cP. It also demonstrated a short dispersion time (15 s) and minimal agglomeration (0.5%) in hot water (80 °C). These findings highlight potential applications of ethanolic extrusion for developing various convenient whole grain instant powders with a high viscosity while maintaining the dietary fiber content.

Comminution technologies in the pharmaceutical industry: a comprehensive review with recent advances

Abstract Comminution processes play a pivotal role in diverse applications, ranging from food processing, to mining and materials engineering. The pharmaceutical industry is no exception, with an increased focus on particle engineering to overcome the growing challenges related to the complexity of new drug molecules such as poor water solubility or stability issues. Additionally, the preparation of powders for pulmonary, transdermal, topical, ophthalmic, oral or parenteral administration often requires specific particle size requirements. Thus, milling technologies offer an excellent option for controlling particle size, improving the stability, dissolution, absorption rate, and bioavailability of poorly water-soluble drugs. They also contribute to enhancing pharmaceutical forms and overall product performance. This review highlights the different types of technologies used for comminution, the respective advantages and drawbacks, as well as connected topics including feed material properties, analytical techniques, process analytical technology, process safety, new top-down technologies and key information to consider when selecting a technology. Thus, an in-depth approach of comminution in the pharmaceutical industry is presented. This compilation serves as a source of comprehensive information for those who decide to initiate research projects in this field, or to update their existing literature knowledge and understanding.

Low-temperature preparation of nano-sized Al2TiO5 powder via non-hydrolytic sol-gel route with Al metal as the aluminum source

Al2TiO5 powder was prepared using the non-hydrolytic sol-gel route, with Al powder and titanium tetrachloride as precursor materials. The synthesized powder was characterized via XRD, DSC-TG, TEM, FTIR, FE-SEM, and laser particle size analyzer. The results indicated that Al2TiO5 powder can be synthesized at 750 ℃ via gelation when the aluminum-to-alcohol molar ratio was 1:14 and titanium tetrachloride concentration was 0.9 mol/L. The average particle size of Al2TiO5 powder was 80 nm using reflux gelation and 35 nm with direct drying gelation. The Al metal utilized the hydrogen chloride produced in situ to activate itself and formed Al-O-Ti hetero-bonds through non-hydrolytic polycondensation. The Al-O-Ti hetero-bonds underwent an exothermic reaction at around 695 ℃ to form Al2TiO5. This research has broadened the range of precursor materials available for preparing Al2TiO5 using the non-hydrolytic sol-gel route.

Effect of Powder Preparation Techniques on Microstructure, Mechanical Properties, and Wear Behaviors of Graphene-Reinforced Copper Matrix Composites

In this study, the effect of powder preparation techniques on microstructure, mechanical properties, and wear behaviors of graphene-reinforced copper matrix (Gr/Cu) composites was investigated. The composite powders were prepared by two different techniques including high-energy ball (HEB) milling and nanoscale dispersion (ND). The obtained results showed that the ND technique allows the preparation of the composite powder with a smaller and more uniform grain size compared to the HEB technique. By adding Gr, the mechanical properties and wear resistance of the composite were much improved compared to pure Cu. In addition, the composite using the powder prepared by the ND technique exhibits the best performance with the improvement in hardness (40%), tensile strength (66%) and wear resistance (38%) compared to pure Cu. This results from the uniform grain size of the Cu matrix and the good bonding between Cu matrix and Gr. The strengthening mechanisms were also analyzed to clarify the contribution of the powder preparation techniques on the load transfer strengthening mechanisms of the prepared composite.

Preparation of functional supplement powder using nanoliposome-containing marine bioactive compounds.

The demand for marine bioactive compounds as therapeutic agents in supplements or functional foods has increased. However, their instability, bitter taste, and potential degradation during digestion have hindered their widespread use. To overcome these problems, a functional supplement powder was produced using the encapsulation technique of nanoliposomes containing shrimp lipid extract, fish oil (FO), and fish protein hydrolysate. Chitosan and whey protein concentrate (WPC) were used to coat the nanoliposomes in mono/bilayer and composite forms, followed by freeze-drying for 72h. The physicochemical characteristics, nutritional, in vitro release, and sensory evaluation were investigated. The WPC-monolayer treatment exhibited the highest solubility (28.83mg/100g), encapsulation efficiency (97.67%), and polyunsaturated fatty acids (PUFAs). Although the mono/bilayer treatments of whey protein showed lower docosahexaenoic acid and eicosapentaenoic acid than FO, they presented a favorable amino acid profile. Compared to acidic stomach conditions, the release in the intestine was higher. Incorporating 1.5g of the supplement powder per 100g of milk can meet an individual's daily nutritional needs for essential amino acids and PUFAs. Therefore, encapsulating marine bioactive compounds in liposomal carriers could be a beneficial approach to their direct use as a nutritious powder.

Protocol Refinement for the Development of Coconut Inflorescence Powder

Aims: Coconut inflorescence holds significant potential as a nutraceutical due to its rich composition of bioactive compounds, including vitamins, minerals, and antioxidants. Its use in promoting health and preventing diseases has made it a valuable ingredient in both traditional medicine and modern functional foods. The aim of the study is the protocol refinement for the development of coconut inflorescence powder with acceptable moisture content and superior sensory quality. Study Design: Completely randomized design (CRD). Place and Duration of Study: Department of Plantation, Spices, Medicinal and Aromatic Crops, College of Agriculture, Vellayani, Kerala Agricultural University, between May 2024 and October 2024. Methodology: In the present study, coconut inflorescence was harvested at 5-6 months before inflorescence opening, size reduced (1 cm3 pieces), and precooked by adopting different methods, viz., steaming, boiling, dry roasting, and microwave cooking (non-precooked inflorescence was used as the control). The precooked inflorescence pieces were dried by different drying methods viz., hot-air oven drying at 600C (Control), cabinet drier at 600C, 700C, 800C and solar drying for developing coconut inflorescence powder (CIP). CIP was analyzed for moisture content and sensory quality. Results: CIP prepared by steaming the coconut inflorescence pieces for 30 minutes and drying in cabinet dryer at 600C (C1D1) recorded the least moisture content, 1.83±0.07 per cent. However, CIP prepared by boiling (95-1000C) the inflorescence pieces by submerging for 30 minutes and drying in cabinet dryer at 600C (C2D1) showed the highest mean rank value for all the sensory attributes viz., colour (735.50), consistency (730.63), flavour (730.68), mouthfeel (734.75) and taste (735.23) on a nine-point hedonic scale with a moisture content, 4.20±0.04 per cent. The lowest mean rank value for colour was recorded by C1D1 and C2D0 (211.06). The lowest values for consistency, mouthfeel, flavour and taste were observed for the treatments C4D1 (289.81), C4D1 (290.61), C4D0 (226.05) and C0D0 (216.50), respectively. Hence, C2D1 was identified as the best precooking and drying method for the preparation of coconut inflorescence powder.

Phytochemical properties and antioxidative activities of ginseng superfine powders prepared by wet grinding method with high-pressure homogenization

Ginseng is widely used in agricultural products, dietary health supplements, and pharmaceutical preparations, which has significant market potential. It is of great significance to develop a more efficient and environmentally friendly production process of ginseng powder. However, ginseng is difficult to be milled to an ideal state by dry grinding method because of its higher fiber content. In the meantime, ginseng has high viscosity when suspended in a liquid, which can pose challenges during wet grinding processes. In order to develop a production process for ginseng powder with excellent physicochemical properties, three kinds of powders were obtained by both dry grinding method (ball mill) and wet grinding method (colloid mill&high-pressure homogenizer) in this study. The powder properties, structural properties, saponin contents,and antioxidant activity of different ginseng powders were also investigated. The results showed that wet grinding technology using a high-pressure homogenization process could significantly improve the powder properties，including the particle size, specific surface area, span value, water holding capacity, and appearance. Moreover, both the saponin contents and the antioxidant activity of the powder had been significantly enhanced. The findings indicated that high-pressure homogenization process was a promising technique for producing plant powders rich in bioactive compounds, which could enhance their bioactivity. The method was argued to be a significant alternative technology for production of ginseng ultrafine powders. Furthermore, it offered theoretical and technical support for the application of the high-pressure homogenization process in the preparation of ultrafine powders with reduced particle sizes from high-fiber plants.

One-step synthesis of spherical Al3Ta alloy powder by electrolyzing solid Ta2O5 in molten fluorides

Aluminum-tantalum powders are emerging as new raw materials for additive manufacturing (AM) technologies, but their preparation in bulk quantities and in powder form via conventional metallurgical methods is challenging. In this study, we report a one-step synthesis of spherical Al3Ta powder by direct electrolyzing solid Ta2O5 cathode (vs. a graphite anode) in molten Na3AlF6-K3AlF6-AlF3-LiF-Al2O3. Cyclic voltammetry and constant potential electrolysis techniques were employed to characterize the electrochemical reaction process, along with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for the structural and morphological analyses. The process involves an initial Ta2O5 electro-deoxygenation process, the subsequent electrodeposition of Al3+ on the formed Ta particles and an in-situ alloying process. The innovative use of Ta2O5 cathodes with a novel hierarchical porous structure allows for a controlled transformation of cathode particle morphology and facilitates the rapid generation of nanoscale tantalum particles. Al3+ from the electrolyte is then electrodeposited onto these particles, initiating an in-situ alloying reaction. This is an exothermic process that facilitates the diffusion of aluminum atoms into tantalum, and reduces the interfacial energy promoting the formation of spherical Al3Ta particles. Such powders are in demand for AM techniques. The findings may now guide the way to establishing the electrochemical route for the short-process preparation of other high-temperature alloy powders.

Preparation of Powder from Butterfly Pea Plant (Clitoria Ternatea) for Pharmaceutical Applications

The butterfly pea plant, scientifically known as Clitoria ternatea, is valuable medicinal herb with long history of traditional use in various cultures. This research focuses on the preparation of powder from the butterfly pea plant, exploring the optimal methods for drying, grinding, and storing the plant material. The study also evaluates the phytochemical content, physical properties, and potential pharmaceutical applications of the resulting powder. The findings suggest that standardized preparation techniques can enhance the medicinal value of the butterfly pea plant, making it a viable option for use in various pharmaceutical formulations

FUNCTIONAL OPTICAL MATERIALS BASED ON AEROGELS

Sol-chemistry is an efficient physico-chemical method for the preparation of porous glassy or nanocrystalline materials with tailored electrical, thermal or optical properties. This paper focuses on the dependence preparation–structure-properties of hydrophobic silica aerogel granules, powders and composites with a potential application as optical materials. Using the technique of subcritical preparation of silica aerogel powders, multicolour emitting composites containing Eu(phen)2(NO3 )3 or Tb(phen)2(NO3 )3 nanocrystals are obtained and characterized with luminescence spectroscopy, quantum yield determination and texture measurements. A dependence of the luminescence quantum yield on the degree of hydrophobicity α of the silica aerogel powders is described.

Corrosion resistance and wear behavior of CoCrFeNiMn@Gr high entropy alloy-based composite coatings prepared by laser cladding

In this study, we utilize laser cladding to apply a CoCrFeNiMn HEA with 2 wt.% few-layer graphene (Gr) coating onto the surface of Q235B mild steel. Alcohol stirring method was used for HEA and Gr preparation of composite powder. Raman spectroscopy and energy dispersion spectroscope (EDS) indicate the successful mixing of HEA and Gr powders, with Gr adhering to the surface of the HEA powder in a lamellar structure. The X-ray diffraction (XRD), scanning electron microscope (SEM), EDS, and Electron backscatter diffraction (EBSD) analyses revealed that grain refinement and the formation of fine carbide-hard phases in the HEA/Gr coating improve microhardness and wear resistance. The average Schmidt factors of the coating decreased from 0.47 to 0.45 with the addition of Gr, indicating enhanced resistance to plastic deformation and anisotropy. Nanoindentation experiments demonstrated that the HEA/Gr coatings exhibit superior resistance to plastic deformation, effectively enhancing the coating’s durability against spalling under stress and wear conditions. The microhardness of the HEA/Gr coating increased by 99.25%, and the wear rate decreased by 86.31% compared to the HEA coating alone. The open circuit potential (OCP), linear polarization curve, Tafel curves, electrochemical impedance spectroscopy (EIS), and Mott-Schottky tests all indicated that the HEA/Gr coating possesses superior corrosion resistance. X-ray Photoelectron Spectroscopy (XPS) results suggest that the passivation film of the HEA/Gr coating, which contains more oxides and less hydroxide, is more protective and denser, thereby slowing the corrosion rate.

Deformation behavior of harmonic structure designed CoCrFeMnNi HE alloys

This paper presents the deformation behavior of CoCrFeMnNi high-entropy alloy (HEA) produced from plastically undeformed and deformed powders. The investigation commenced with the preparation of ball-milled HEA powder at 90ks and 180ks, with a ball-to-powder ratio of 2:1, to induce severe plastic deformation on the outer layer of the HEA powder. Subsequently, the plastically undeformed and deformed HEA powders were successfully consolidated in a spark plasma sintering (SPS) furnace. The SEM observations revealed that the sintered plastically undeformed HEA powder exhibited conventional homogeneous microstructures (Homo), while sintered deformed HEA powders exhibited a regulated bimodal grain distribution known as harmonic structure (HS). The mechanical properties of the materials were characterized by performing tensile tests at room temperature (RT) and a low temperature of 193 K. The HS HEA exhibited an increase in proof strength of 16%–40%, while the ultimate tensile strength (UTS) increased by 8%–20% compared to the Homo HEA. Moreover, the strain hardening rate (SHR) curve indicates that both Homo and HS HEA exhibited oscillatory behavior at low temperature. However, Homo HEA exhibited more pronounced oscillation than HS HEA. The current results indicate that oscillatory behavior in the SHR curve is indicative of twin deformation. At low temperatures, the high rate of twinning deformation in Homo HEA was attributed to its higher ductility, while a good combination of high strength and high ductility produced by HS material was found to be influenced by HS design in addition to twinning deformation.

Additive manufacturing of polyamide 12 bulk structures using directed energy deposition with a thulium laser: Effect of process conditions on morphology and mechanical performance

Laser-based directed energy deposition of polymers (DED-LB/P) is a highly flexible additive manufacturing process capable of fabricating three-dimensional structures with a high degree of customization on free-form surfaces. In this article, the manufacturability of polyamide 12 bulk structures using DED-LB/P in combination with a thulium laser operating at a wavelength of 1.94 μm is investigated for the first time. The typical absorption bands at this wavelength eliminate the need for additives such as carbon-based nanoparticles, which would limit the range of applications. The generated structures were analyzed regarding porosity, thermal behavior, and mechanical properties to evaluate the potential of DED-LB/P with a thulium laser. As a consequence of the evaporation of absorbed moisture or ethanol residues resulting from powder preparation, a thermal pretreatment of the polymer powder reduced the porosity of the DED-LB/P structures to 0.9%. Depending on the processing parameters, the crystallinity of the produced structures ranged from 25.6% to 29.9%. For the tensile tests, the required geometries were milled from the DED-LB/P bulk structures. The results show that an ultimate tensile strength of up to 52 MPa, an elongation at break of up to 58%, and Young's modulus of up to 1590 MPa can be achieved. These remarkable mechanical properties are primarily attributed to the complete melting of the powder particles in DED-LB/P and the improved surface quality resulting from the milling process.

Optimization of the Homogenization Process of Ginseng Superfine Powder to Improve Its Powder Characteristics and Bioavailability.

As consumer demands evolve for health supplements, traditional ginseng products are facing challenges in enhancing their powder characteristics and bioavailability. The objective of this study was to prepare a novel ginseng superfine powder using a high-pressure homogenization (HPH) process. Response surface methodology was employed to determine the effects of HPH parameters (pressure, number of passes, and concentration) on particle size and the dissolution of the saponin components of the superfine powders. The Box-Behnken design of experiments was applied to ascertain the optimal HPH parameters for the smallest particle size and the highest dissolution of the saponin components. For the powders obtained at different parameters, the characterization of tap density, bulk density, flowability, water-holding capacity, appearance, and taste were observed. The optimized experimental conditions for the HPH process were as follows: 15,000 psi (pressure), 3 (number of passes), and 1 kg/L (concentration). The optimized values were 55 μm (particle size) and 83 mg/g (dissolution of the saponin components), respectively. The method offered technical support for the application of the HPH process in the preparation of ginseng powders. The objects of this research could be broadened to include a diverse array of botanical materials, addressing contemporary demands for cost-effectiveness and sustainability within the industry.

Three-Dimensional Numerical Simulation of High-Speed Shear Crushing of High-Density Fluid

Plasma atomization is a technology that can produce high sphericity, small particle diameters, and high-purity copper powder, which is of great significance for the development of metal additive manufacturing. At present, although plasma atomization can realize the industrial preparation of spherical copper powder, there are still some problems, such as unclear understanding of the atomization process and a lack of theoretical support for powder quality control. This leads to the inability to predict the average particle diameter of powder in advance based on the actual atomization conditions and to optimize the process parameters, which seriously affects the further development of the plasma atomization process. We mainly studied the non-stationary simulation of a DC argon plasma torch. The purpose of this paper was to study the specific influence law of the average particle diameter of the powder in the process of plasma atomization by means of numerical simulation and experimental observation. The aim was to establish the mapping relationship between the atomization condition and the average particle diameter of the powder and realize the controllable preparation of the plasma atomized powder. At the same time, we used industrial-grade plasma atomization equipment to carry out pulverizing experiments to verify the plasma atomization theory and the powder average particle diameter control scheme proposed in this paper, thus proving the reliability of this study.

Cultivation and Characterization of Oyster Mushroom and Its Application as Confectionaries

This study represents the cultivation of oyster mushrooms at room temperature, preparation of mushroom powder and ready-to-eat cookies from the combination of cocoa powder and mushroom powder with long shelf life. Nowadays, people are facing difficulties in meeting their daily nutritional needs through ready-to-eat foods, prompting the exploration of white oyster mushrooms as an ingredient for making cookies, potentially serving as an emergency food product. Mushroom farming is gaining popularity day by day. The mushrooms have lots of potential to be used in the diet for taking advantage of the nutraceutical properties of bioactive compounds due to lower fat and higher protein substance. The drift is absent from the canned item toward new and dried mushroom sales. Oyster mushrooms are popular due to their nutritional, medicinal, and potential commercial value. They can be cultivated using agro-waste raw materials such as rice straw and wheat straw. We prepare mushroom cookies that provide protein, carbohydrates, fat, and crude fiber. A wide selection of shapes and sizes, high digestibility, high energy value, relatively low production costs, convenience, and long shelf life contribute to their popularity.

Preparation of spherical Gd2Zr2O7 powders by RF induction thermal plasma process

Spherical Gd2Zr2O7 (GZO) powders with a uniform particle size distribution are successfully prepared using a novel industrial approach, which combines spray-drying process and thermal plasma sintering technology together. In this, GZO powders with pyrochlore structure as the main phase are first synthesized via a solid-state reactive route using a mixture of the milled Gd2O3 powders and ZrO2 powders as starting materials. The influence of sintering temperature on the microstructure of prepared powders is researched. Then, GZO granules are prepared after wet-grinding and spray-drying process, which exhibit a spherical shape with the average particle size of 46.5 μm. RF induction thermal plasma is finally used to sinter the granulated particles, and the influence of feeding rate on the properties of spherical powders is investigated. The apparent density of plasma sintered GZO spherical powders is increased from 1.53 g/cm3 to 2.29 g/cm3 when the feeding rate of granulated powders is 80 g/min, and further increased up to 3.90 g/cm3 when the feeding rate is 15 g/min. Such powders are in potential demand for plasma sprayed coatings and additive manufacturing techniques, and the successful synthesis of spherical GZO powders may guide the way toward the preparation of many other spherical rare earth zirconates powders.

Experimental and simulation studies to optimize the mechanical alloying process of ODS-FeCrAl alloy powder

Oxide dispersion strengthened (ODS) FeCrAl alloy exhibits superior mechanical qualities at high temperatures and resistance to neutron irradiation, making it a highly promising material for accident-tolerant fuel cladding. The preparation of ODS-FeCrAl alloy powder by mechanical alloying can mix Y2O3 and FeCrAl alloy powder uniformly and promote the uniform dispersion of nanoscale oxide particles in the alloy matrix. The preparation of ODS-FeCrAl alloy powder by the mechanical alloying method is greatly influenced by the rotational speed. Therefore, this study uses a combination of experiments and numerical simulation to investigate the effects of different rotational speeds on the microscopic morphology, particle size and force of alloy powder during the ball milling process. The mechanically alloyed powder was subjected to XRD inspection to determine the optimum ball milling time at each rotational speed by means of the maximum lattice distortion, and then the powder micromorphology and particle size were analyzed. Then the forces on the powder and grinding ball during the ball milling process were analyzed by numerical simulation, and it was found that the collision force and normal force played a dominant role in the ball milling process. The combined experimental and simulation results determined that the ODS-FeCrAl alloy powder obtained by ball milling at 300 rpm for 35 h had the largest lattice distortion, fine grain size and uniform particle size, which achieved the best mechanical alloying effect.