Commercial Powder Research Articles

Electrochemical Impedance Spectroscopy Analysis of 45S5 Bioglass Coating on After Oxidation of CoCrW Alloy

Implants and prostheses, which are used to replace a missing or damaged structure in living organisms, must show all the necessary mechanical, tribological, electrochemical and biocompatibility properties together. CoCr alloys are often preferred biometals for their good mechanical strength and wear resistance, especially in dental and orthopedic implants. Although these alloys show good corrosion resistance in terms of electrochemical behavior as well as other good properties, when CoCr alloys come into contact with bone tissue, their surfaces show bioinert properties in terms of tissue formation between the implant and bone tissue. Therefore, both their corrosion behavior and biocompatibility properties need to be improved. In this study, CoCrW alloys produced by selective laser melting were coated with commercial 45S5 bioglass powder, a bioactive material, by electrophoretic deposition method. In order to improve the adhesion after coating, CoCrW alloys were subjected to electrochemical etching process during coating. After the coating process was completed, untreated, oxidized, untreated-coated and oxidized-coated samples were examined by electrochemical impedance spectroscopy (EIS) after open circuit potential measurements to investigate their corrosion behavior. As a result of the corrosion tests, it was determined that the oxidized-coated sample showed the best condition compared to the other samples in EIS analyzes.

Highly Sensitive and Stable Flexible Smart Sensors Based on Commercial Carbon Fiber Powder Inks.

With the fast development of the smart lifestyle in recent years, simple and flexible body condition monitoring has become more and more important. However, currently, commercially available motion-sensing devices always lack flexibility or at a high cost. This article has fully explored the merits of a commercial and easily available material of carbon fiber powder (CFP) and prepared CFP-based screen printing inks. This conductive ink can be directly and quickly printed onto a variety of different flexible common substrates, such as paper, cotton fabrics, etc., to prepare flexible sensors. At the same time, as a result of the good photothermal performance and conductivity of CFP, the printed flexible sensors have fast and stable performance on thermal and human motion detection. The use of CFP as the smart element to construct a wearable device will offer a choice for the intelligent industry.

Evaluating the Potential of Vegetable Powders as Nitrite Replacements in Cured Pork Sausages: Effects of Different Processing Methods to Produce Chinese Cabbage and Radish Powders.

This study investigated the potential of Chinese cabbage and radish powders as natural sources of nitrite in ground pork sausages. Four vegetable powders from Chinese cabbage and radish, depending on the processing method, were prepared for evaluation: filtered Chinese cabbage juice powder (FCJP), crushed Chinese cabbage powder (CCP), filtered radish juice powder (FRJP), and crushed radish powder (CRP). Both FCJP and FRJP from filtered juice of Chinese cabbages and radishes had higher total soluble solids and water soluble index compared to CCP and CRP from crushed Chinese cabbages and radishes. Additionally, FRJP and CRP showed a higher nitrate content than CCP and FCJP. The evaluation of vegetable powders against products containing sodium nitrite (control) or commercial vegetable powder in ground pork sausages showed that the use of FRJP and CRP resulted in similar levels of CIE a* compared to the control, whereas those cured with FCJP or CCP resulted in lower CIE a* values. However, regardless of the type and processing method of vegetables, all sausages treated with vegetable powders were similar in terms of cured pigment, total pigment, curing efficiency, and lipid oxidation compared with the control. Although lower hardness was observed in sausages treated with FRJP, no other treatments affected textural attributes. These results indicate that FRJP and CRP have great potential as natural curing agents for replacing nitrite in cured sausages. The use of powders obtained from filtered juices may provide extended utility as vegetable-based curing methods for other meat products.

Enhancement of Flexural Strength by Slip Casting Cordierite Ceramics with h-BN Nanoparticles

In this study, we enhanced the flexural strength of cordierite ceramics by incorporating h-BN (hexagonal boron nitride) nanoparticles, facilitated by the slip casting process. Initially, commercial cordierite powder with an average particle size of 10 mm underwent a ball-milling process to reduce the size to 2.5 mm and simultaneously achieve a narrower particle size distribution. The resulting slurry, composed of 67% solid content, exhibited improved stability during the slip casting process for both pristine cordierite and the mixture containing 1 – 2 wt% h-BN nanoparticles. After sintering, the bulk material containing 2wt% h-BN nanoparticles demonstrated a remarkable flexural strength of 174.8 MPa, a significant improvement compared to the initial 119.5 MPa obtained without the addition of h-BN. It is worth noting that the introduction of h-BN nanoparticles did not induce substantial changes in dielectric constant and thermal conductivity, indicating that the desired mechanical enhancement did not compromise other crucial material properties. This research demonstrates a successful approach to concurrently optimize the flexural strength, dielectric constants, and thermal conductivity of cordierite ceramics. This breakthrough opens up new avenues for advanced applications in a wide range of fields, from electronics to aerospace, where high-strength, thermally stable materials are in demand.

Sintering densification behavior of nano-ITO powder with high oxygen vacancy induced via plasma stimulation

With the growing electronics display industry, indium tin oxide (ITO) powder plays a crucial role in target preparation. To enhance the sintering performance of ITO powder, a high-activity nano ITO powder was prepared using plasma spraying, and compared to a commercial powder. This study aimed to investigate the effects of different preparation methods on powder morphology, dispersibility, oxygen vacancy concentration, and the physical properties of powders on target density, surface morphology, grain size, element distribution, and solid solubility. The results indicate that the plasma spraying high-activity nano ITO powder exhibits better dispersibility, higher oxygen vacancy concentration, and a specific surface area of up to 88.39 m2/g compared to the commercial powder. Under normal pressure sintering conditions, plasma spraying nanoscale ITO powder exhibits higher sintering activity, leading to easier densification of ceramic targets with reduced porosity, more uniform surface grains, and significant stepped growth between surface grains. High-resolution transmission electron microscopy (HRTEM) analysis suggests that targets prepared with high-activity powder have greater tin solubility in indium oxide compared to traditional commercial ceramic targets. This article further explores the relationship between powder specific surface area, oxygen vacancy, and sintering activity, along with the formation mechanism of high oxygen vacancy.

Biomass derived activated carbons in wastewater treatment – The aim of metallurgical industry

In the presented study, two commercial powder activated carbons (ACs) produced from low-cost biomass: coconut shells and wooden chips, were used in the adsorption process. The treated solution was wastewater obtained from production area of metallurgical industrial plant, which was analysed before and after the adsorption process using atomic absorption spectrometry (AAS). The adsorption process proceeded at two pH levels 7 and 9. The removed pollutants were Cd, Co, Cu, Ni, Sb, and Zn. Based on the adsorption results, the correlation between adsorption efficiency, pH and ACs properties was determined. The complicated composition of the tested wastewater causes that the adsorption mechanism did not have to be obvious due to the phenomena occurring in the multi-component system. Both ACs adsorbed ions efficiently, better results were obtained for AC derived from coconut shells. It was found that higher pH correlate with higher adsorption efficiency for every checked type of ions. AC with higher iodine number, mainly basic surface groups and higher micropores volume had better efficiency for adsorption Cd, Co, Cu, Ni and Zn. AC with higher surface area and presence of acidic surface groups only, had better efficiency in Sb adsorption process.

Catalytic Conversion of Glycerol to Lactic Acid Over Cu-Based Catalysts

Copper (I, II) oxide powders were tested for glycerol conversion to lactic acid under alkaline conditions. Fresh and spent catalysts were characterized using powder X-ray diffraction, Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy, the BET-nitrogen adsorption method and FTIR spectroscopy. In all cases, an almost complete in situ reduction of Cu (I, II) oxides into metallic Cu was observed, even after one catalytic run. Moreover, all the samples of spent catalysts showed similar catalytic activity regardless of their initial form and particle size. Commercial copper powders, prepared copper powders and in situ reduced copper catalysts were tested under the same conditions to compare their catalytic activity. It was shown that the in situ reduced copper catalyst had similar activity to the specially prepared copper powders and much higher activity compared to the commercial copper powders. The in situ reduced copper catalyst exhibited rather high stability. The glycerol conversion and lactic acid selectivity were about 98% and 70%, respectively, after ten catalytic cycles.

Tableting behavior of freeze and spray-dried excipients in pharmaceutical formulations

Most of biopharmaceuticals, in their liquid form, are prone to instabilities during storage. In order to improve their stability, lyophilization is the most commonly used drying technique in the pharmaceutical industry. In addition, certain applications of biopharmaceutical products can be considered by oral administration and tablets are the most frequent solid pharmaceutical dosage form used for oral route. Thus, the tableting properties of freeze-dried products used as cryo and lyoprotectant could be a key element for future pharmaceutical developments and applications. In this study, we investigated the properties that might play a particular role in the specific compaction behavior of freeze-dried excipients. The tableting properties of freeze-dried trehalose, lactose and mannitol were investigated and compared to other forms of these excipients (spray-dried, commercial crystalline and commercial crystalline milled powders). The obtained results showed a specific behavior in terms of compressibility, tabletability and brittleness for the amorphous powders obtained after freeze-drying. The comparison with the other powders showed that this specific tableting behavior is linked to both the specific texture and the physical state (amorphization) of these freeze-dried powders.

Understanding the effect of bondcoat surface treatment on enhanced lifetime of suspension plasma sprayed thermal barrier coatings

Thermal barrier coatings (TBCs) are extensively used in gas turbine engines in power generation and aerospace applications. Improvements in TBC performance and lifetime are continuously pursued by the gas turbine industry. Suspension plasma spraying (SPS) has shown promising results in recent years as it could produce a porous columnar TBC microstructure exhibiting low thermal conductivity and high durability. Further improvements in lifetime and fundamental understanding of failure mechanisms would lead to their wider application.Lifetime of a TBC system is dependent not only on the topcoat microstructure and chemistry, but also on topcoat-bondcoat interface and bondcoat characteristics as they influence the growth rate of thermally grown oxide (TGO) layer as well as the mismatch stresses generated in the topcoat during operation. Moreover, in SPS TBCs, the column density and porosity in the topcoat are also affected by the bondcoat surface roughness which in turn affects TBC lifetime. In previous work, it was shown that bondcoat surface treatment by shot peening followed by light grit blasting can significantly enhance the cyclic lifetime of SPS TBCs.The objective of this work was to gain further insight into the lifetime improvements due to surface treatment of bondcoat. Commercial NiCoCrAlY powder was deposited by high velocity air fuel (HVAF) and high velocity oxy fuel (HVOF) spraying while SPS was used to deposit yttria stabilised zirconia topcoat. Before spraying the topcoat, the bondcoat samples were subjected to vacuum heat treatment, shot peening, and/or grit blasting. Residual stress measurements were performed by X-ray diffraction on samples with different variants of bondcoat treatments and compared with Almen strip tests. The lifetime was examined by thermal cyclic fatigue testing. The relationships between changes in bondcoat surface roughness, residual stress state and microstructure due to surface treatments, and resultant topcoat microstructure and lifetime were studied and discussed.

Cu Promoted the Dynamic Evolution of Ni-Based Catalysts for Polyethylene Terephthalate Plastic Upcycling.

Upcycling plastic wastes into value-added chemicals is a promising approach to put end-of-life plastic wastes back into their ecocycle. As one of the polyesters that is used daily, polyethylene terephthalate (PET) plastic waste is employed here as the model substrate. Herein, a nickel (Ni)-based catalyst was prepared via electrochemically depositing copper (Cu) species on Ni foam (NiCu/NF). The NiCu/NF formed Cu/CuO and Ni/NiO/Ni(OH)2 core-shell structures before electrolysis and reconstructed into NiOOH and CuOOH/Cu(OH)2 active species during the ethylene glycol (EG) oxidation. After oxidation, the Cu and Ni species evolved into more reduced species. An indirect mechanism was identified as the main EG oxidation (EGOR) mechanism. In EGOR, NiCu60s/NF catalyst exhibited an optimal Faradaic efficiency (FE, 95.8%) and yield rate (0.70 mmol cm-2 h-1) for formate production. Also, over 80% FE of formate was achieved when a commercial PET plastic powder hydrolysate was applied. Furthermore, commercial PET plastic water bottle waste was employed as a substrate for electrocatalytic upcycling, and pure terephthalic acid (TPA) was recovered only after 1 h electrolysis. Lastly, density functional theory (DFT) calculation revealed that the key role of Cu was significantly reducing the Gibbs free-energy barrier (ΔG) of EGOR's rate-determining step (RDS), promoting catalysts' dynamic evolution, and facilitating the C-C bond cleavage.

New insights into optical properties, and applications of Zr-doped BaTiO3

The present work scrutinizes a few uses of barium titanate BaTi1–xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles, which are an innovative and highly promising material for a variety of applications, including optical applications; and waste water treatment. To estimate the quality of a synthesized powder relative to an already existing commercial powder, the samples were prepared using cheaper raw materials and simpler, faster procedures than those reported in other literature at lower annealing durations and temperatures. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), and Raman spectroscopy, which confirmed the coarse nature of the samples and the system's tetragonality. Furthermore, UV–visible absorbance of all compositions was studied. It has been determined that optical transition is directly allowed after extensive research, and the optical band gap (Eg) values increase with increasing (Zr4+) ion concentration. The derivation of absorption spectrum fitting (DASF) technique was used to support the type of transition and calculate the value of the coefficient of electronic transition (n). Samples can perform overall water splitting and CO2 reduction processes. The Langmuir and Freundlich isotherms were used to comprehend the procedure of adsorption on the investigated samples. The BaTi0.8Zr0.2O3 has been used to successfully remove 99.9% of heavy metals (Cr6+) from wastewater. The obtained results provide new insights into the control of the structure, and optical behaviors in BaTi1–xZrxO3.

SiC-YAG Coating Microstructure Optimization Through Powder Feedstock Manufacturing Process Control

A silicon carbide/yttrium aluminum garnet (SiC/YAG) composite powder feedstock material developed and patented by NTNU (Norway) in 2012 has been used to produce industrial SiC thermal spray coatings since 2014. This powder is the first of its kind in the thermal spray industry. The commercial powder is produced by the agglomerated and sintered route (A&S), making it suitable mostly for High-Velocity Oxygen Fuel, but it can also be produced by the sintered and crushed (S&C) manufacturing route for Atmospheric Plasma Spray (APS). In this work, a S&C route is proposed using jaw crusher, hammer mill, and ball milling techniques. The resulting powders were then deposited using APS and were compared with the reference A&S powder. The chemistry and the microstructure of the powders and coatings were characterized using electron microscopy, x-ray diffraction, and Vickers microhardness. The S&C powders showed a density higher than the A&S powder and a blocky morphology. The S&C powders had almost no internal porosity and kept the same chemical composition as the A&S version. The coatings obtained with the S&C powders outperformed the A&S coatings, having less porosity, higher hardness, and no secondary phases.

Investigating the effect of anchoring groups modified comb-like polycarboxylate hyperdispersants on dispersion and stability in dispersed dyes

Comb-like hyperdispersants are widely used for the dispersion of liquid dispersed dyes (LDDs), because of the molecular structure of comb, in which the effective steric hindrance effects provided by polymer side chains and the adsorption force provided by anchoring groups, resulting in the dispersant to be firmly adsorbed on the surface of the dye. However, the mechanism by which the anchoring groups in this dispersant affect the dispersion and stability of LDDs is still unclear. Herein, three types of anchoring group modified comb-like polycarboxylate hyperdispersants were synthesized to explore the effect of anchoring groups on stability and dispersibility, in which the anchoring groups from the monomers of 2-vinylnaphthalene (2-VNP), styrene (St), and 4-vinylbiphenyl (4-VBP). The optimal sand grinding conditions and dispersion stability of the modified hyperdispersants were comprehensively investigated. 2-VNP modified hyperdispersant (DPN) possessed higher grinding efficiency and better dispersion stability than those of St (DPS) and 4-VBP modified hyperdispersants (DPB). The results of atomic force microscope (AFM) and quartz crystal microbalance (QCM) indicated that DPN exhibited higher adsorption force (2.16 mN/m) than that the DPS (0.648 mN/m) and DPB (1.56 mN/m), thereby improving the adsorption strength of dispersants and DDs, stabling the dispersion effect of LDDs. In addition, the dyeing performance of the prepared LDDs on polyester fabric was further investigated. It was found that these LDDs acquired a faster dyeing rate, higher K/S values and rubbing color fastness, and lower chemical oxygen demand (COD) of residual liquid than commercial powder DDs, due to the higher adsorption force on the DDs surface provided good colloidal stability in the high temperatures dye bath. We expect that this study will provide important mechanistic insights into the development of hyperdispersants for LDDs controlled by high adsorption force anchoring groups.

Investigation of the In Vitro Immunomodulatory Effects of Extracts from Green-Lipped Mussels (Perna canaliculus)

The immune system plays a crucial role in defending the body against foreign invaders, and the balance of various polyunsaturated fatty acids, such as alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), can impact immune cell functions and overall immune responses. This study aimed to assess the effectiveness of mussel oil extracts in modulating inflammatory responses by analysing their effects on immune cell lines and cytokine expression. Four different mussel oil extracts were obtained using two extraction methods (organic solvent and supercritical CO2 extraction) from two tissue sources (fresh and commercial). These extracts were then tested at various concentrations on T lymphocyte (Jurkat) cells, monocytes, and macrophages (THP-1 and U-937). Cytokine levels were quantified using ELISA. The results showed that the solvent-extracted samples had a dose-dependent effect on tumour necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) cytokine secretion in THP-1 and U937 cells, with the extract from a commercial mussel powder being more efficient than the extract from fresh powder. However, supercritical CO2 samples showed elevated cytokine secretion levels despite their high omega-3 content. Furthermore, 100 ug/mL extract from fresh powder successfully reduced interleukin-2 (IL-2) secretion while maintaining cell viability after stimulation. The study demonstrated that solvent-extracted mussel oil can effectively regulate cytokine secretion, modulate immune cell activation, and alleviate inflammation. These findings offer valuable insights into using mussel oil extracts to treat inflammatory disorders and enhance immune responses.

New structural features and pinning-evolved coercivity mechanism: A potential route for developing high coercivities in anisotropic Sm-Fe-N material

Sm-Fe-N material holds immense promise as new material for developing next generation permanent magnets. However, the achievement of high coercivity in this material remains a big challenge, and moreover new coercivity theories beyond the commonly considered nucleation-type mechanism needs exploration. This study describes both the yielding of anisotropic Sm-Fe-N powders with high coercivities and the discovery of new coercivity mechanism by a systematic study using a designed milling preparation method. As a result, a random-direction cleavage behavior with unexpected XRD peak shifts and formation of new micron-sized flower-like particles were found in the yielded Sm-Fe-N powders. The grain sizes of the powders are of nanoscale dimension and they refine gradually as the milling time increases. The measured coercivity is up to 15.0 kOe, which is a substantial increase of approximately 36.4% compared to the original commercial powders and among the highest reported values via the milling preparation method (commonly below 13 kOe). The yielded powders also demonstrate a new dual-type coercivity mechanism (combing both nucleation-type and pinning-type control effect), and the improved pining effect contributes to the high coercivities. This study opens the door of utilizing pinning effect for achieving high coercivities in anisotropic Sm-Fe-N material.

Green synthesis of nanosized Tantalum carbide (TaC) via natural polymer/tantalum oxide hybrid composites: A sustainable approach towards enhanced processing and properties

This study provides a green method for producing nanosized tantalum carbide (TaC) by pyrolyzing natural polymer (Gum karaya)/tantalum oxide hybrid composites, which is both sustainable and environmentally benign. The carbothermal reduction, carried out at 1500 °C, produces cubic TaC with a cell constant of ao=4.451 Å. The synthesised TaC reveals a near spherical morphology with an average size of 200 nm, far smaller than commercial TaC. The synthesised TaC displays a beginning oxidation temperature of 420 °C, as compared to the commercial powder (500 °C). Incorporating 5 wt% as-synthesized TaC to commercial TaC results in an impressive relative density of 98%, demonstrating the TaC ability as an excellent sintering aid. This green synthesis not only reduces the environmental impact of conventional methods, but also provides improved characteristics of nanosized TaC for advanced applications, contributing to the field of green nanotechnology by emphasizing safer production methods.

Synthesis of magnesium hydroxide powder and dry powders for application in extinguishing petroleum fires

AbstractFire extinguishing agents are an important factor in the fight against fires. In this study, a new composite powder (CSPMS) was synthesized and used to extinguish fires caused by petroleum products. SiO2 nanoparticles, Mg(OH)2 nanoparticles, and nanocomposites of NH4H2PO4/chitosan (CSP) were combined to generate CSPMS powder. The structure and morphology of the material were characterized using methods such as XRD, SEM, FTIR, etc. The results showed that the synthesized Mg(OH)2 nanoparticle size ranged from 20 to 30 nm, and the NH4H2PO4 nanoparticle size ranged from 800 to 900 nm on the chitosan surface. The CSPMS material had particle sizes ranging from 2 to 3 µm, with a uniform distribution of SiO2 nanoparticles (50–100 nm) and Mg(OH)2 nanoparticles on the surface. The powdered materials were applied to extinguish gasoline and oil fires. CSPMS sample demonstrated the best fire extinguishing time and powder consumption (5.8 s and 12.2 g, respectively) and CO emission below the threshold of 400 ppm. Small‐scale fire extinguishing tests showed that CSPMS powder had better fire extinguishing capability, cooling time, and CO gas adsorption ability compared to commercial fire extinguishing powder.

Polydopamine-Coated Silk Fiber with Controllable Length for Enhanced Hemostatic Application.

The development of highly effective hemostatic materials with high biocompatibility and outstanding performance is vital to the field of biomaterials. In this study, we develop a hemostatic fiber material that exhibits high biocompatibility and excellent performance. By incorporating polydopamine (PDA) into the alkaline treatment of silk fibroin (SF), we achieve PDA-coated SF fibers with lengths that can be controlled by the alkaline concentration. The PDA coating significantly enhances the hemostatic ability of the silk fibers and exhibits superior performance in both in vitro and ex vivo experiments. By performing animal studies involving a mouse liver puncture model and a femoral vein incision model, we demonstrate the remarkable hemostatic capability of the PDA-coated SF fibers, as evidenced by the lower blood loss compared to that of a commercial hemostat powder. These findings highlight the potential of applying a PDA-assisted alkaline treatment to SF fibers to efficiently create hemostatic fibers with controllable lengths, which would be promising candidates for clinical hemostatic applications.

Fabrication of highly conducting undoped ZnO ceramics by flash sintering

Highly conducting undoped ZnO ceramics were fabricated by flash sintering using commercial pure ZnO powder as a model system. The flash-sintered samples with diameters of 15 mm and heights of 2 mm exhibited relative densities ranging from 93.6% to 97.1% and room-temperature electrical conductivities between 205 and 590 S/cm. X-ray diffraction and Raman spectra indicated a high concentration of oxygen vacancies and zinc interstitials in the flash-sintered samples, increasing the carrier concentration. Detailed microstructural analyses show that clean grain boundaries and the morphology and distribution of impurities in flash-sintered samples are favorable for improving carrier mobility. Additionally, flash sintering has the advantage of reducing conditions, which reduces acceptor defects at ZnO grain boundaries, lowers Schottky barriers, and increases carrier mobility. The results show that flash sintering can synergistically enhance the carrier concentration and mobility in ZnO ceramics, making it a promising technique for fabricating highly conducting ZnO ceramics.

Effect of pore structure on the impact toughness of copper-infiltrated sintered steel

Copper-infiltrated sintered steel is a prominent area of research in powder metallurgy, with a particular focus on enhancing impact toughness. In this study, sintered steels with varying pore structures were prepared using iron powders and infiltrated with copper to investigate their impact toughness. The results indicate a significant improvement in the impact toughness of the sintered steels with concentrated iron particle sizes. The density of the samples increased from 6.85 g cm−3 to 7.55 g cm−3 through copper infiltration. The large copper-phase sample with the particle size of 150 μm exhibits an impact toughness as high as 41.09 J cm−2, and its fracture morphology mainly shows transgranular fractures of large iron particles. It is 1.5 times that of the sample made from commercial iron powders which measured 27.46 J cm−2. This enhancement is primarily attributed to the precipitation of γ-Fe within the large copper phase, thereby enhancing the copper phase and transferring the load into large iron particles. A brief mechanism of γ-Fe precipitation in the large copper-phase has been provided.