Powder Method Research Articles

Effects of Tungsten Addition on the Microstructure and Properties of FeCoCrNiAl High-Entropy Alloy Coatings Fabricated via Laser Cladding.

This study examines the effects of different addition levels of tungsten (W) content on the microstructure, corrosion resistance, wear resistance, microhardness, and phase composition of coatings made from FeCoCrNiAl high-entropy alloy (HEA) using the laser cladding technique. Using a preset powder method, FeCoCrNiAlWx (where x represents the molar fraction of W, x = 0.0, 0.2, 0.4, 0.6, 0.8) HEA coatings were cladded onto the surface of 45 steel. The different cladding materials were tested for dry friction by using a reciprocating friction and wear testing machine. Subsequently, the detailed analysis of the microstructure, phase composition, corrosion resistance, wear traces, and hardness characteristics were carried out using a scanning electron microscope (SEM), X-ray diffractometer (XRD), electrochemical workstation, and microhardness tester. The results reveal that as the W content increases, the macro-morphology of the FeCoCrNiAlWx HEA cladding coating deteriorates; the microstructure of the FeCoCrNiAlWx HEA cladding coating, composed of μ phase and face-centered cubic solid solution, undergoes an evolution process from dendritic crystals to cellular crystals. Notably, with the increase in W content, the average microhardness of the cladding coating shows a significant upward trend, with FeCoCrNiAlW0.8 reaching an average hardness of 756.83 HV0.2, which is 2.97 times higher than the 45 steel substrate. At the same time, the friction coefficient of the cladding coating gradually decreases, indicating enhanced wear resistance. Specifically, the friction coefficients of FeCoCrNiAlW0.6 and FeCoCrNiAlW0.8 are similar, approximately 0.527. The friction and wear mechanisms are mainly adhesive and abrasive wear. In a 3.5 wt.% NaCl solution, the increase in W content results in a positive shift in the corrosion potential of the cladding coating. The FeCoCrNiAlW0.8 exhibits a corrosion potential approximately 403 mV higher than that of FeCoCrNiAl. The corrosion current density significantly decreases from 5.43 × 10-6 A/cm2 to 5.26 × 10-9 A/cm2, which suggests a significant enhancement in the corrosion resistance of the cladding coating.

Positive and Negative Impacts of Low-Pressure Cold Plasma as a Decontamination Method for Red Chili Powder (Capsicum Annuum L.)

Positive and Negative Impacts of Low-Pressure Cold Plasma as a Decontamination Method for Red Chili Powder (<i>Capsicum Annuum L</i>.)

Effects of foaming agent types and ratio with red flesh pitaya puree on physicochemical properties of foam-mat dried powder

Red flesh pitaya (Hylocereus sp.) is a highly perishable fruit with a high content of bioactive compound. It has short shelf life due to high moisture content and water activity. In this study, red flesh pitaya (RFP) powder was produced via foam mat drying method (FMD) with egg albumen (EA) and whey protein isolate (WPI) as the foaming agents. This study aimed to investigate the effect of foaming agent types and its ratio with RFP puree on physicochemical properties of foam-mat dried RFP powder. RFP fruit was incorporated and foamed with EA and WPI at 0 %, 5 %, 15 % and 30 % w/w concentrations. The foam was dried at 65 ?C for 5 hours. The powders were analysed for its moisture content, water activity, solubility, density, colour, fiber and total soluble solid (TSS). Decreasing the puree concentration from 85% to 55% while increasing the concentration of foaming agents (0% to 30%) has decreased the value of moisture content, water activity, crude fiber and colour properties. Meanwhile, the solubility, density and TSS of the foam-mat dried RFP powder was increased with increasing the concentration of both foaming agents (decreasing the ratio of RFP puree) used. The quality of powder foamed with WPI has produced the lowest in moisture content (2.86 %) and water activity (0.18), high in solubility (71.03 %), densities (0.56 g/cm3 and 0.84 g/cm3) and high in TSS (9.61). Meanwhile, the quality of samples foamed with 5% EA and 80% of RDF puree observed high in fiber content (3.38 %) and mostly retains the colour properties. FMD technique may be applied as the preservation technique of fruit powder as it has produced the powder with low moisture content and good colour properties within a short time and is more economical.

Invitro Activity of Mineral Trioxide Aggregate Modification from Rice Hull Ash Silica and Calcium Oxide from Clamshells

The impact of SrO particles and hydroxyapatite (HA) on the characteristics of Mineral Trioxide Aggregate (MTA) from silica Rice Husk Ash (RHA) and Precipitated Calcium Carbonate (PCC) from clam shell has been studied in this research. Silica and calcium oxide are used as material to form tricalcium silicate (C3S) and dicalcium silicate (C2S) in MTA. Bi2O3 and SrO were added in MTA with 18% (w/w) total percentage. MTA was made with a sol-gel process and used catalyst NH3. After synthesis, material was calcined at 1000 oC for 3 h. HA was added at percentages of 3, 6, and 9% in 5% SrO modified MTA to see the effect of its addition on the material. The modified MTA (MTA-SrO-HA) were hydrated water using water to powder method with ratio of 3:1. The MTA-SrO5/HA6 showed higher compressive strength and dentine interaction to the commercial MTA (Proroot brand) in days 3 and 7. This material had potential as a root canal filling in dental endodontic treatment.

Preparation and properties of FeS/iron-based self-lubricating materials by chemical nickel plating-mechanical alloying

PurposeThis paper aims to investigate the effect of chemical nickel plating and mechanical alloying on the mechanical and tribological properties of FeS/iron-based self-lubricating materials as well as the wear mechanism of the materials.Design/methodology/approachSurface modification of FeS powder was carried out by chemical nickel plating method and mechanical alloying of mixed powder by ball milling. The mechanical properties of the material were tested by tribological testing by M-200 ring block type friction and wear tester. Optical microscope was used to observe the surface morphology of the material and the transfer film on the surface of the mate parts, and scanning electron microscope and EDS were used to characterize the wear surface.FindingsMechanical alloying ball milling was carried out so that the lubricating particles in the matrix are uniformly dispersed; nickel-plated layer enhances the interfacial bonding of FeS and the matrix, and the combination of the two improves the mechanical properties of the material, and at the same time the friction side of the surface of the lubrication of FeS lubricant transfer film formed is denser and more intact, and the friction coefficient of friction side and the wear rate of the material have been greatly reduced.Originality/valueThis work aims to improve the mechanical and tribological properties of FeS/iron-based self-lubricating materials and to provide a reference for the preparation of materials with excellent overall properties.

Mechanochemical Recycling of Flexible Polyurethane Foam Scraps for Quantitative Replacement of Polyol Using Wedge-Block-Reinforced Extruder.

Recycling flexible polyurethane foam (F-PUF) scraps is difficult due to the material's high cross-linking structure. In this work, a wedge-block-reinforced extruder with a considerable enhanced shear extrusion and stretching area between the rotating screw and the stationary wedge blocks was utilized to recycle F-PUF scraps into powder containing surface-active hydroxyl groups. The powder was then utilized for the quantitative replacement of polyol in the foaming process. Characterizations showed that the continuous shear extrusion and stretching during the extrusion process reduced the volume mean diameter (VMD) of the F-PUF powder obtained by extruding it three times at room temperature to reach 54 μm. The -OH number (OHN) of the powder prepared by extruding it three times reached 19.51 mgKOH/g due to the mechanochemical effect of the powdering method. The F-PUF containing recycled powder used to quantitively replace 10 wt.% polyol was similar in microstructure and chemical structure to the original F-PUF, with a compression set of 2%, indentation load deflection of 21.3 lbf, resilience of 43.4%, air permeability of 815.7 L/m2·s, tensile strength of 73.0 Kpa, and tear strength of 2.3 N/cm, indicating that the recycling method has potential for industrial applications.

A new organic compound (C9H12N2O2): Crystal structure, characterization, Hirshfeld surface analysis, electronic properties, NLO properties, DFT calculation and molecular docking

A crystal of the organic chromophore N-propyl-4-nitroaniline was synthesized via the process of gradual solvent evaporation. The parameter values of the cell were calculated using single-crystal X-ray diffraction. In order to learn more about the band gap energy and optical quality, a UV–Vis–NIR spectral study was carried out. The lower cut-off wavelength is shown to be as low as 233 nm, and the direct optical band gap is determined to be 4.89 eV. This study delves into the intricate interplay between solvent polarity and the electronic properties of the titled compound, employing TD-DFT calculations. Notably, the analysis unveils a nonlinear correlation between solvent polarity and absorption wavelength, with an observed red-shift of up to 22 nm in select polar solvents. Furthermore, a distinct trend emerges in the variation of the energy gap between HOMO and LUMO, revealing a solvent-specific impact ranging from 0.279 eV to 0.378 eV. These findings offer a nuanced understanding of how solvent environments intricately modulate electronic behavior. Using FTIR spectrum analysis, the frequencies of the vibrations were determined. The Kurtz-Perry powder method verified the existence of Second Harmonic Generation (SHG). At the B3LYP/6–311++G (d, p) level of theory, DFT was also used to look at the crystal molecular structure geometry, charge transfer interactions between molecules, thermodynamic properties and hyperpolarizability.

The effects of calcination heating rate on phase formation and structure of zircon sand-derived zirconia

Abstract Phase formation and structure examination has been conducted to study the effects of thermal treatment and heating rates on zircon (ZrSiO4) sand-derived zirconia (ZrO2). A preliminary investigation of the elements present in the sand using XRF revealed that Zr was the major element, corresponding to 92.4% of the sample. The zirconia precursor was synthesized through a three-stage process that involves purifying zircon powder, alkali fusion, and co-precipitation method. The zirconia crystal was obtained by heating the sample to 700, 800 and 900 °C with heating rates of 5 and 10 °C/min, respectively. The formation of tetragonal zirconia (t-ZrO2) with space group P42/nmc is shown in a qualitative study of all sample XRD patterns. Furthermore, Rietveld analysis was used to determine crystal structure parameters including lattice parameters and tetragonality. The calcination temperature and heating rate decide the phase, t-ZrO2 crystallite size, and tetragonality. Furthermore, calcining to 700 and 800 °C created t-ZrO2, however, elevated temperature to 900 °C lead to t→m transformation. The t-ZrO2 size increases with temperature between 700 and 900 °C, range of 9 and 15 nm. Meanwhile, the tetragonality of t-ZrO2 tends to decrease due to m-ZrO2 being present.

Determination of selective laser melting process parameters of tungsten carbide powders coated with nickel via electroless plating for improved interface properties

Tungsten carbide powders are commonly used at various industrial applications due to their high hardness. However, these powders may exhibit low binding and processing challenges without a binder. Therefore, various binding methods such as electroless Ni coating are used to hold WC powders together, increase their processability and improve the mechanical properties of the final product. Electroless Ni plating plays an important role in the use of WC powders, especially in processes such as selective laser melting. The structural, tribological, and mechanical properties of parts manufactured by SLM method are significantly influenced by the parameters employed in the process. Hence, optimizing process variables is essential to unlock the full potential of this advanced manufacturing technique. The main objective of this study was to identify the optimum process parameters for the SLM method of WC-Ni composite powders, which were prepared by coating WC powder materials with electroless Ni. Experimental investigations focused on analyzing the laser power, scanning speed, and hatch spacing parameters. The effects of these parameters on the mechanical and tribological properties of WC-Ni composite material were investigated using microhardness tester, tribometer device, optical microscope, 3D optical profilometer and scanning electron microscope. Eventually, it was determined that the manufacturing parameters employed in the SLM method had a significant impact on relative density, microstructure, surface roughness, hardness, and tribological properties. Samples exhibited a relative density of nearly 99%, and the highest observed hardness value was 1962 HV. This article supports a specialized SLM manufacturing process developed specifically to enhance durability and performance across a broad spectrum of industrial applications through interface improvement and the optimization of manufacturing parameters.

Novel activation method of waste concrete powder for sustainable clinker-free binder

This study investigates the environmental and mechanical implications of incorporating silica fume into lime-activated thermo-mechanically treated waste concrete powder (TMWCP) to develop a sustainable clinker-free binder. The novel activation method involves thermo-mechanical treatment of WCP, followed by lime and calcium formate chemical activation. The results demonstrated that incorporating silica fume enhanced the pozzolanic reactivity, which led to the formation of C–S–H, pore refinement, and a dramatic increase in compressive strength. For instance, the incorporation of 20 % and 25 % silica fume exhibited compressive strength of 46 MPa and 43 MPa after 28 days of curing. The developed clinker-free binder with the addition of 20 % silica fume demonstrated a reduction in mineral resource consumption of 99.3 % and CO2 emissions of 13 % and 69.3 % compared to the sample without silica fume and ordinary Portland cement, respectively. This study offers a promising avenue for the widespread utilization of WCP as an environmentally friendly clinker-free binder.

Influence of particle size fraction and bioactive compound contents on the biological activities of Solanum torvum L. leaf powder extracts

This study investigates the bioactive compound content and biological activities of raw powder extracts and particle size fractions from Solanum torvum leaves. The leaves, harvested from Douala, were processed into powders and subsequently divided into different fractions. Methanolic extracts of these powders were analyzed for their content of bioactive compounds (total polyphenols, total flavonoids, and condensed tannins), antioxidant (DPPH, ABTS, FRAP assays), and antimicrobial (bacterial and fungal) activities. The particle size fraction of 250-400 µm constitutes the largest proportion (33.41%) of the raw powder. The highest contents of bioactive compounds are found in the 200-250, 400-500, and &lt; 125 µm fractions for total polyphenols (44.62 ± 0.19 mg GEA/100 ml extract), total flavonoids (14.47 ± 0.37 mg QE/100 ml extract), and condensed tannins (22.79 ± 0.12 mg CE/100 ml extract), respectively. The antioxidant activity of extracts from 500-800µm fraction improved their DPPH and ABTS assays by 31.50% and 40.44% compared to the raw powder. The same fraction (500-800 µm) and the raw powder extracts demonstrated bactericidal activities, while the 125-200, 200-250, and ≥ 800 µm fraction extracts exhibited moderate and significant antifungal activities against several bacterial and fungal strains, respectively. These biological activities are primarily attributed to the average flavonoid contents, which become more accessible in extracts after fractionation. This method of processing powder suggests that no plant powder should be disregarded or rejected due to its low content of bioactive compounds.

Neutron diffraction: a primer

Abstract Because of the neutron’s special properties, neutron diffraction may be considered one of the most powerful techniques for structure determination of crystalline and related matter. Neutrons can be released from nuclear fission, from spallation processes, and also from low-energy nuclear reactions, and they can then be used in powder, time-of-flight, texture, single crystal, and other techniques, all of which are perfectly suited to clarify crystal and magnetic structures. With high neutron flux and sufficient brilliance, neutron diffraction also excels for diffuse scattering, for in situ and operando studies as well as for high-pressure experiments of today’s materials. For these, the wave-like neutron’s infinite advantage (isotope specific, magnetic) is crucial to answering important scientific questions, for example, on the structure and dynamics of light atoms in energy conversion and storage materials, magnetic matter, or protein structures. In this primer, we summarize the current state of neutron diffraction (and how it came to be), but also look at recent advances and new ideas, e.g., the design of new instruments, and what follows from that.

Study Of The Structural Properties Of Al-Zn Compounds Manufactured By Powder Technology And Copper-Reinforced

Due to the importance of aluminium compounds in many industrial fields, therefore, in this study, copper-reinforced (Al-Zn) compounds were prepared in different proportions (0%, 0.4%, 1.2%, and 2%), using the powder technique. The structural properties of the compounds under study were investigated using XRD and EDS tests at room temperature. It was found through the XRD results that the samples were polycrystalline (cubic, tetragonal, monoclinic, and hexagonal). The results of the crystallinity analysis showed that sample (Al-Zn-(0%)Cu) was (12.73%) crystallized, sample (Al-Zn-(0.4%)Cu) was (32.125%) crystallized, sample (Al-Zn-(1.2%)Cu) was (42.771%) crystallized, and sample (Al-Zn-(2%)Cu) was (50.179%) crystallized. Theoretical density of the phases was determined for each sample using independent calculations, taking into consideration some factors such as variations in atomic mass, the number of atoms of the constituent elements, and the size of the unit cell.

Co-precipitation process as an effective and viable route for proton-conducting solid oxide fuel cell applications

BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb) is one of the most popular electrolyte materials in proton ceramic fuel cells (PCFCs). The synthesizing method and properties of BCZYYb powders have a significant impact on the sintering activity of electrolyte materials. In this work, the BCZYYb electrolyte was synthesized by ammonium bicarbonate co-precipitation method (CPT), and was compared with the powder produced by solid-state reaction (SSR) and sol-gel (SG) methods. XRD results show the BCZYYb powder synthesized by the CPT method belongs to orthorhombic crystal system with a space group of Pmcn (No. 62) and the refined lattice parameters are a = 8.774 Å, b = 6.173 Å, and c = 6.203 Å. In humid air atmosphere, the total conductivity at 650 °C and the activation energy for the BCZYYb powder prepared via the CPT method was 2.1 × 10−2 S cm−1 and 0.46 eV, respectively, as compared with 1.9 × 10−2 S cm−1 and 0.45 eV for the SSR method, and 1.8 × 10−2 S cm−1 and 0.44 eV for the SG method. Under similar testing conditions, the measured peak power densities were 0.51, 0.35, and 0.40 W cm−2 at 650 °C for the anode supported PCFCs using electrolyte powder prepared via CPT, SSR and SG methods, respectively, which proves the CPT method is an effective and viable route for PCFCs applications.

A Review of Latent Fingerprint Developed Powder from using Natural Materials

The fingerprint development technique is one of the oldest methods used in forensic science and is a common method of identifying perpetrators. [1] Different powder methods have been accounted for the development of latent fingerprints on various surfaces in the literature, such as lead, titanium oxide, Rhodamine B dye etc., all powders mentioned had been used for the development of latent fingerprints. Some of these methods using powders when exposed to humans, may lead to health problems, and also these methods are expensive in nature [2]. Various fingerprint powder preparations used for fingerprints have a color or contrast and a sticky material for good adhesion [3]. The goal of this review is to compile the research works done by various experts to identify commonly available, everyday materials as fingerprint powders such materials from various categories such as food powders, plant materials, minerals, cosmetics, carbon-based materials, and miscellaneous powders [1]. The powder method is a quick and easy approach to the development of latent fingerprints on porous and nonporous surface [4]. proposing a new powder method, which is simple, nontoxic to human health, cheap in nature, and as well can be utilized for the development of latent fingerprints on various contrast surfaces [2].

Development of a dry powder insufflation device with application in in vitro cell-based assays in the context of respiratory delivery

Research on pharmaceutical dry powders has been increasing worldwide, along with increased therapeutic strategies for an application through the pulmonary or the nasal routes. In vitro methodologies and tests that mimic the respiratory environment and the process of inhalation itself are, thus, essential. The literature frequently reports cell-based in vitro assays that involve testing the dry powders in suspension. This experimental setting is not adequate, as both the lung and the nasal cavity are devoid of abundant liquid. However, devices that permit powder insufflation over cells in culture are either scarce or technically complex and expensive, which is not feasible in early stages of research. In this context, this work proposes the development of a device that allows the delivery of dry powders onto cell surfaces, thus simulating inhalation more appropriately. Subsequently, a quartz crystal microbalance (QCM) was used to establish a technique enabling the determination of dry powder deposition profiles. Additionally, the determination of the viability of respiratory cells (A549) after the insufflation of a dry powder using the developed device was performed. In all, a prototype for dry powder insufflation was designed and developed, using 3D printing methods for its production. It allowed the homogenous dispersion of the insufflated powders over a petri dish and a QCM crystal, and a more detailed study on how dry powders disperse over the supports. The device, already protected by a patent, still requires further improvement, especially regarding the method for powder weighing and the efficiency of the insufflation process, which is being addressed. The impact of insufflation of air and of locust bean gum (LBG)-based microparticles revealed absence of cytotoxic effect, as cell viability roughly above 70 % was always determined.

Particle-Based Photoelectrodes for PEC Water Splitting: Concepts and Perspectives.

This comprehensive review delves into the intricacies of the photoelectrochemical (PEC) water splitting process, specifically focusing on the design, fabrication, and optimization of particle-based photoelectrodes for efficient green hydrogen production. These photoelectrodes, composed of semiconductor materials, potentially harness light energy and generate charge carriers, driving water oxidation and reduction reactions. The versatility of particle-based photoelectrodes as a platform for investigating and enhancing various semiconductor candidates is explored, particularly the emerging complex oxides with compelling charge transfer properties. However, the challenges presented by many factors influencing the performance and stability of these photoelectrodes, including particle size, shape, composition, morphology, surface modification, and electrode configuration, are highlighted. The review introduces the fundamental principles of semiconductor photoelectrodes for PEC water splitting, presents an exhaustive overview of different synthesis methods for semiconductor powders and their assembly into photoelectrodes, and discusses recent advances and challenges in photoelectrode material development. It concludes by offering promising strategies for improving photoelectrode performance and stability, such as the adoption of novel architectures and heterojunctions.

Interferometric characterization of high-frequency piezoelectric effects in hydroxyapatite thin films

Hydroxyapatite (HAp) qualities such as biocompatibility and piezoelectricity make it an excellent material for biomedical applications. Here, HAp thin film samples were fabricated onto silica substrates to study their piezoelectric behavior with optical interference. Thin solid films were deposited using previously synthesized HAp powder, sol-gel, and spin-coating techniques. The samples were characterized by scanning electron microscopy, energy dispersive X-ray, Raman, and UV-Vis spectroscopies. The statical piezoelectric effect of the samples was studied by using a finite element method and computational software. Additionally, an experimental Bode analysis allows computing the internal electrical components of the films using high-frequency AC voltage. The electrical behavior is related to the equivalent circuit of a piezoelectric crystal, which indicates the range of frequencies where the electromechanical effect is maximum. A Sagnac interferometer was used to characterize the strain in the HAp as a function of the electrical input frequency. The displacement of the interferometric fringe pattern allows us to estimate the change in the thickness of the sample and compute the piezoelectric constant. The synthesis of HAp thin films with piezoelectric properties provides an effective way to produce sensors and actuators for technological applications.

Strengthening of Mullite Ceramics with Silver Reinforcements

Mullite-based composites reinforced with silver particles were obtained by powder techniques. Composites were sintered after an intense mixing of the precursor powders. It was found that additions of silver have a strong effect on the mechanical properties, since fracture toughness was increased up to 350%. The microstructure of composites presents grains with flakes morphology.

High strength and ductility on Ni6W2Cr4Fe8Ti1 high entropy alloys by selective laser melting

High entropy alloys (HEAs) have a good application potential in the preparation of high temperature service parts with complex shapes in additive manufacturing. Powder bed fusion (PBF) is a prominent type of additive manufacturing process that utilizes the thermal energy to bind powder materials together to build up plastic or metallic parts. However, the traditional gas atomization method (GA) often produce alloy powder (containing refractory element) with uneven composition, affecting the quality and performance of specimens. That is why innovative or opposite classical production powder methods are in demand for the PBF. It is worth noting that mechanical alloying technology overcomes the limitation of high temperature alloying of HEA containing refractory elements and realizes solid alloying of insoluble elements. In this paper, high entropy alloy Ni6W2Cr4Fe8Ti1 containing refractory elements is designed by means of composition control. Its spherical powders with uniform composition were successfully prepared by the new mechanical alloying - high temperature remelting spheroidization dual process (DP) method. The treated powder composition is evenly distributed with particle sizes ranging from 15 to 28 μm. And the spheroidization rate has exceeded 98.23% at 1943 K. The sample value of YS and UTS on Ni6W2Cr4Fe8Ti1 (DP-SLM) has increased by 35.7%, 45.5% and 27.3%, respectively in additive manufacturing, compared to GA-SLM. The ability to produce refractory HEA through DP method will make it possible to manufacture complex geometry shapes at a reasonable cost. It offers theoretical guidance to manufacture fine grain materials with high strength and ductility of new HEA components.