Powder Particles Research Articles

High-efficiency synthesis of colloidal silica via suppression of foam layer

As an important fundamental material, colloidal silica is widely used in many fields. Hydrolysis of elemental silicon is an important method for the preparation of colloidal silica. This method has been widely studied because of its simple process, low cost, easy control of colloidal particle size and good stability. However, this method has the problem of low reaction conversion rate (RCR). This paper proposed an efficient method to increase RCR of colloidal silica by inhibiting the formation of a foam layer. After the size of the silicon powder particle, reaction time, and the defoamer types were optimized, the defoamer of hydrophobic fumed silica could effectively inhibit the increase of foam layer and improve the yield of colloidal silica, the RCR was significantly increased from 54.8 % to 85 % within 4 h. This research provides an innovative strategy for the efficient chemical synthesis of colloidal silica.

Effect of Laser Powder Bed Fusion Parameters on the Evolution of Melt Pool, Densification, Microstructure, and Hardness in 420 Stainless Steel Parts

Laser powder bed fusion (LPBF) involves depositing, melting, and solidifying metal powder particles layer by layer to create 3D components. In this study, a deep fundamental understanding on how process parameters—laser power, scan speed, and hatch spacing—affect the melt pool, densification, microstructure, hardness, and thermal behavior of 420 stainless steel (420SS) parts produced by such technology is provided. The conducted investigation considers five levels of laser power and hatch spacing, and four scan speeds. Optimal single tracks, based on geometry and profile, are achieved with laser powers between 40 and 80 W and a scan speed of 10 mm s−1. In the multitrack analysis, it is indicated that a dense, smooth surface is obtained with a hatch spacing of 250 μm, corresponding to an overlapping rate of ≈30%. The 420SS samples show high densification (≈99%) and low surface roughness (≈3.62 μm). The microstructure consisted of martensite laths and retained austenite. The hardness and thermal conductivity of the samples are measured at 540 HV and 15.3 W m−1 K−1, respectively. In this study, the understanding of the process–structure–property relationships in LPBF of 420SS is expanded.

Enhanced anisotropy of Pr-Nd-Fe-B HDDR magnetic powders by regulating the hydrogen decrepitated process

The evolution of microstructures for different hydrogen decrepitated routes was investigated in hydrogenation-disproportionation-desorption-recombination (HDDR) magnetic powders, with particular focus on the fracture of the SC heat-treated alloy during two-step hydrogen decrepitation (HD) and the influence of the first step temperature on magnetic properties. As the temperature increases, the properties of the magnetic powders increase and then decrease, the optimized performance of HDDR magnetic powders was obtained with Br=1.45 T, (BH)max=393 kJ·m−3, DOA=0.79 when the first HD temperature is 65°C. The microscopic analysis shows that there are two problems in the one-step HD route: one is that the particle size is larger ∼150 μm and there are incomplete fractured cracks, the particle surface is more PrNd-rich phase, which leads to different reaction rates between the surface and center in HDDR particles, and the texture orientation of the fine grains at the edge of surface and crack is disordered. The second issue is that HD grains have significant angular difference with the c-axis orientation in incomplete fractured grain clusters, which is directly inherited by the HDDR magnetic powder, resulting in a misalignment texture. In comparison, the two-step HD process effectively addresses the issues derived from one-step HD process. Not only is the grain size of HDDR magnetic powders uniform and the width of the thin grain boundary phases (GBs) is less than the exchange coupling length, but also (Fe+Co) content exceeding 30 at% in GBs with weak magnetism. This is beneficial for enhancing exchange coupling effect between adjacent grains. Moreover, magnetic powder particle exhibits single-domain characteristics, which improves the grain texture orientation. This research provides a new insight for the development of high-orientation and high-performance HDDR magnetic powders.

Structure and properties of powders obtained by electrodispersion of pure Nickel metal waste in distilled water

Purpose. Investigation of the composition, structure and properties of powder materials obtained by electrodispersion of nickel waste of the PNK-0T1 brand in an oxygen-containing medium – distilled water.Methods. To determine the composition, structure and properties of powder materials, samples of powders obtained from waste nickel grade PNK-0T1 were studied. The powder material was obtained by electroerosive dispersion in distilled water. Microanalysis of powder particles was carried out using a scanning electron microscope, an analysis of the size distribution of powder particles was obtained using a particle size analyzer, an X-ray spectral microanalysis of powder particles was carried out using an energy-dispersive X-ray analyzer embedded in a scanning electron microscope, an analysis of the phase composition of powder particles was carried out using X-ray diffraction on the diffractometer.Results. During the study, it was revealed that the shape of the particles obtained from nickel powders is spherical and elliptical, and agglomerates of smaller particles are also noted on the increase. Oxygen and nickel are present in the composition of powder materials. The phases of pure nickel and nickel oxide NiO are marked in the phase composition. From the analysis of the granulometric histogram, it follows that the particle size spread varies in the range of 0.26...18.62 microns, the average volume diameter of the particles was 5.2 microns.Conclusion. The obtained research results can be used to develop a new heavy pseudo-alloy using metal waste from expensive raw materials by the method of electroerosive dispersion, followed by improvement and optimization of the composition and structure of the alloy.

Development of applicator to deliver hydrogel precursor powder for esophageal stricture prevention after endoscopic submucosal dissection

Esophageal stricture can be an adverse event following endoscopic submucosal dissection (ESD). Although particle-shaped materials could prevent post-ESD esophageal strictures, no applicator can efficiently deliver them to the ESD wound site. In this study, we developed an applicator to endoscopically deliver powders by combining polytetrafluoroethylene (PTFE) tubes and five types of catheter-tip nozzles with different structures fabricated using a 3D printer. The applicator with a T3S4 nozzle, with three and four holes on the tip and side, respectively, achieved lateral powder delivery from the endoscope catheter tip. The adhesion percentage to the ESD wound site, estimated using the esophagus mimicking model setup with tubes and wetted laboratory wipes, increased from 25 % (without the nozzle) to 55 % (with the T3S4 nozzle). In the computational fluid dynamics (CFD) simulation without a nozzle, the powder particles went straight, and hardly adhered to the ESD wound site. By contrast, the CFD simulation with the optimized T3S4 nozzle predicted that the adhesion percentage would increase by up to 55 %. Optimization of the axial position of the catheter affected the powder delivery efficiency, while optimizing the radial position and angle affected the homogeneity of powder delivery. An in vivo porcine ESD model using the developed applicator confirmed efficient and homogeneous powder delivery to the ESD wound site. These results suggest that the powder applicator development and CFD simulations are effective in treatments using endoscopic powder delivery.

Acceleration of grain boundary diffusion during ultra-fast firing (UHS) of alumina powder compacts

The sintering rate of a ceramic at a given temperature and relative density is often higher if the heating to that sintering temperature is more rapid. This has previous been explained in terms of microstructural coarsening during slow heating, which degrades the sinterability of the body before it reaches the sintering temperature. In this work the sintering of pure alumina with conventional heating rates (CS, 100-900 °C/hour) was compared with ultra-fast firing, using the method known as ultrafast high-temperature sintering (UHS, 120-140 °C/s). Despite the wide difference in heating rate, the SEM microstructures for a given density were similar and a modified Master Sintering Curve analysis of the results showed that the small pore size reduction observed was not sufficient to account for the acceleration in sintering of UHS samples compared with CS. There remained an additional acceleration by a factor of up to ∼20 that was attributed to a higher grain boundary diffusion coefficient in UHS. It is suggested that this is the result of the boundaries forming between powder particles not having time to relax to their lowest energy, most compact structures during UHS, i.e. non-equilibrium grain boundaries. In support of this hypothesis, it is shown that powder compacts that were first partially pre-sintered with conventional heating rates and then subjected to UHS did not show the same acceleration of sintering displayed by UHS of green bodies. The implication is that the slow pre-sintering allowed relaxation of the grain boundaries to low energy structures with low diffusion coefficients.

Theoretical modeling of feedstock-laser energy interaction in directed energy deposition with simultaneous wire and powder feeding

The Laser-based Directed Energy Deposition (L-DED) process is widely employed for the fabrication of numerous metallic parts. It also stands out as a crucial additive manufacturing (AM) technique for creating metal matrix composites (MMCs) reinforced with ceramic particles. The simultaneous deposition of wire and powder feedstocks into the created melt pools on the substrate surface proves advantageous in overcoming the limitations associated with mixed powders in powder deposition alone. The strategy of coaxial wire and powder deposition (CWP-DED) allows for more efficient construction of MMCs with complex geometries and desirable properties. Nevertheless, CWP-DED is a complex multi-phase deposition process that involves highly dynamic interactions among laser beams, wire, and powder particles, influencing laser energy distribution and absorption during the process. This work aims to develop a theoretical model to advance the fundamental understanding of the absorbed and lost laser beam energy by the fed wire and powders in CWP-DED before entering the melt pool. Laser energy absorption coefficients can be calculated based on the Step Wise Heating method to determine the final temperature of the powder particles and wire before entering the melt pool. The experimental validation of the proposed model requires a power meter that fits the CWP-DED system with six inclined laser beams, which is not commercially available so far, to measure the actual output power with and without wire and powder feeding. Consequently, this work presents a detailed explanation of the experimental procedure desired to measure the absorption coefficients of the wire and powder feedstocks and how to validate the proposed model as a future research endeavor. This model plays a vital role in predicting and understanding the amount of heat transferred into the melt pool, which lays a foundation for understanding the complicated melt pool thermodynamics that directly govern the microscopic characteristics and macroscopic properties of the as-built parts.

Effect of spray-drying or fermentation on the solubility and carbohydrate profile of chickpea hydrolysates for beverage formulation

Powder beverage bases were developed using extruded and hydrolyzed chickpea supernatant through freeze-drying. This study evaluated the effects of spray-drying and adjuvant incorporation for producing powders and supernatant fermentation with LAB strains prior freeze-drying on the carbohydrate composition, structural integrity, and physical properties of chickpea beverage base powders. All powders had low insoluble (<0.2%) and soluble (<3%) dietary fiber contents due to processing. Starch content decreased below 9.49% when using adjuvants and 10.61% during fermentation. Both treatments also reduce raffinose oligosaccharide content below 6.1 mM/100 g. Spray-drying and adjuvant addition promoted a more amorphous starch structure, enhancing solubility, while fermentation induced more crystallinity, according to FTIR data. Microscopy showed small particle clusters and lack of birefringence. SEM images revealed starch granule damage from both fermentation and spray-drying, with more uniform particles in spray-dried powders. Spray-drying resulted in the smallest particle sizes (455-457 nm) and higher absolute zeta potential (8.12-9.51), indicating greater stability. Fermentation had the opposite effect, negatively impacting the colloidal system stability. Samples had a pH close to 6, except fermented powders with a pH of 3.6, affecting colloidal stability. Fermentation significantly reduced solubility but without practical implications, as all samples had solubility values over 93%, which is desirable for beverage-based powders. Spray-drying and fermentation altered the carbohydrate profile and structure of the powders. Fermentation prior producing powders may provide benefits, but it slightly decreases the system stability. Spray-drying can be used instead of freeze-drying to produce stable chickpea base powders that are highly soluble.

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.

Effect of Ti/Ta ratio on the microstructure and mechanical properties of Hf20Mo15Nb25Ta20-xTi20+x refractory high-entropy alloys

The limited deformation capacity at room temperature remains a significant challenge in refractory high-entropy alloys (RHEAs). In this study, the fine-grained Hf20Mo15Nb25Ta20-xTi20+x (x = 0, 5, 10, 15) alloys were prepared by mechanical alloying and subsequent spark plasma sintering (SPS), based on precise component regulation. The impact of altering the Ti/Ta ratio (R, R = (20+x)/(20-x)) on the pre-alloyed powders and the as-sintered alloys were investigated. An increase in R-value led to larger powder particle sizes and lower powder yields, which was attributed to the improvement in the plasticity of the pre-alloyed powders. After SPS sintering, the as-sintered alloys were comprised of two BCC solid solution matrices and nanoscale precipitated phases. As the R-value increases, the stability of the microstructure decreases slightly, while the yield strength shows a slight improvement, and the plastic strain experiences a relatively significant enhancement. The as-sintered Hf20Mo15Nb25Ta20-xTi20+x alloys all exhibited an excellent balance of strength and plasticity. Theoretical calculations revealed that the yield strength of the alloys was the result of the combined effect of several strengthening mechanisms, predominantly substitutional solid solution strengthening. Furthermore, a systematic discussion was conducted on the reasons for the improvement in the plasticity of the as-sintered alloys. This study presents an effective approach to enhancing the room temperature deformation capacity of RHEAs, thereby facilitating their broader application.

Highly correlated deposition characteristics between individual elemental powders and elemental powder blends of MoNbTaTi in laser melt deposition

The laser melt deposition process often involves fabricating custom alloys from cost-effective elemental powder blends. However, discrepancies between the nominal ratio of the pre-mixed powders and the final composition of the deposited part are commonly observed due to variations in the material properties of the elemental powders. In this study, separate experiments were employed to investigate the relationship of deposition characteristics between individual elemental powders and elemental powder blends in the laser melt deposition process. To investigate the spatial distribution between elemental powder particles, powder flow characteristics in four different delivery systems were measured. Single-track deposition experiments were deployed to study the real powder catchment efficiency of elemental powder and the final composition of the deposited layer. In addition, a finite element model was established and validated with experimental data to predict the dilution rate and final chemical composition of the deposited layer. The experimental results indicate a strong correlation between the powder catchment efficiency of individual elemental powder and the final composition of the deposited layer. The simulation results agreed well with the actual composition of the deposited track. This study’s findings have the potential to predict and optimize the composition of the desired materials fabricated by elemental powder blends in the laser melt deposition process.

Аналіз процесу ущільнення порошків вольфраму плакованих міддю

The paper analyzes the pressing process of a composite powder of the tungsten-copper system using the basic mathematical equations describing the deformation processes of a porous body as a function of density and pressing pressure. Several theoretical dependences describing different pressing mechanisms are considered, taking into account modern approaches, namely the discrete-contact model and the continuum model of a continuous medium. The most well-known equations, including those of Balshin M.Y., Zhdanovich G.M., and Shtern M.B., are analyzed. It is established that most of them have limited applicability, remaining valid for individual stages of the pressing process and significantly depend on the mechanical properties of the material that determine the predominance of elastic or plastic deformation. At the same time, most equations are focused on single-component powders, which does not correspond to the practice of powdered parts production processes. To test the theoretical dependencies, copper-clad tungsten powder was obtained by chemical vapor deposition from solution. The technological parameters of the cladding process (composition, solution concentration, and deposition time) that determine the quality of the resulting coatings were determined. The morphology of the particles of clad powders and the structure of tungsten-copper pressings were investigated. It is shown that tungsten powder forms a relatively dense framework with a copper layer, respectively, the structure of composite powder pressings is as close as possible to a continuous continuum and is correctly described by an equation based on the theory of continuity of the medium, It has been established that the compaction character of copper-clad tungsten powder differs from that of single-component tungsten powder, which is due to the fact that plastic deformation mechanisms prevail for tungsten-copper composite powders.

Powder coarsening mechanisms of Ti-6Al-4 V with multiple build cycles in laser powder bed fusion

Laser powder bed fusion (LPBF) is an additive manufacturing process which can produce complex 3D parts from digital models. The performance of parts fabricated by LPBF is largely dependent on the characteristics of the powder feedstock, in particular, the particle size distribution. The coarsening of powder particles may limit the potential for reusing powder in further builds, as consistency in powder quality is crucial for ensuring consistent parts performance when using reused powder, especially in aerospace applications. However, there is a lack of systematic understanding regarding the causes and nature of powder coarsening in LPBF. In this work, the characteristics of powder samples from different locations in the build chamber during LPBF were studied to understand the particle size evolution and determine the origin of coarsening, which has not been previously reported. Meanwhile, powder coarsening was found to have a detrimental effect on the relative density and surface quality of as-built parts, highlighting the importance of exploring the mechanisms of powder coarsening and finding ways to control it in LPBF. The relationship between powder in key locations in the build chamber and its effect on powder coarsening has been established. Layer thickness is identified as a critical factor in causing powder coarsening due to the fine powder size characteristic in the powder bed. Spatter, in its various forms, plays a direct or indirect role in powder coarsening. Sintered powders resulting from spatter and the laser scanning borders of as-built parts were observed to contribute to the powder coarsening. Therefore, three main mechanisms (layer thickness, spatter, sintered powder) associated with the powder coarsening are therefore proposed. This work provides insight and potential solutions to control powder coarsening and maintain consistent parts performance.

Enhanced Photocatalytic Hydrogen Production Activity Driven by TiO2/(MoP/CdS): Insights from Powder Particles to Thin Films.

Transitioning from powder photocatalysts to thin film photocatalysts is one of the necessary steps toward industrializing photocatalytic hydrogen production. Herein, we reported the integration of non-noble metal cocatalyst MoP decorated with TiO2 and CdS, forming TiO2/(MoP/CdS) for ultraviolet-visible light utilization. The designed powder TiO2/(MoP/CdS) composites achieved a superior hydrogen production rate of 42.2 mmol g-1 h-1, which is 30.1 times that of TiO2/CdS, performing the highest activity among the TiO2-CdS-based composite photocatalysts. Moreover, we fabricated a thin film from TiO2/(MoP/CdS) powder, which exhibited comparable photocatalytic activity for hydrogen production, achieving 35.5 mmol g-1 h-1 and maintaining long-term stability for 150 h. The outstanding performance was attributed to the ability of the TiO2/(MoP/CdS) composite photocatalysts to absorb both visible and ultraviolet light. Additionally, the heterojunction formed between TiO2 and CdS also played a significant role in the overall photocatalyst activity. This cost-effective catalyst holds promise for future large-scale industrial applications.

Effects of Powder Reuse and Particle Size Distribution on Structural Integrity of Ti-6Al-4V Processed via Laser Beam Directed Energy Deposition

In metal additive manufacturing, reusing collected powder from previous builds is a standard practice driven by the substantial cost of metal powder. This approach not only reduces material expenses but also contributes to sustainability by minimizing waste. Despite its benefits, powder reuse introduces challenges related to maintaining the structural integrity of the components, making it a critical area of ongoing research and innovation. The reuse process can significantly alter powder characteristics, including flowability, size distribution, and chemical composition, subsequently affecting the microstructures and mechanical properties of the final components. Achieving repeatable and consistent printing outcomes requires powder particles to maintain specific and consistent physical and chemical properties. Variations in powder characteristics can lead to inconsistencies in the microstructural features of printed components and the formation of process-induced defects, compromising the quality and reliability of the final products. Thus, optimizing the powder recovery and reuse methodology is essential to ensure that cost reduction and sustainability benefits do not compromise product quality and reliability. This study investigated the impact of powder reuse and particle size distribution on the microstructural and mechanical properties of Ti-6Al-4V specimens fabricated using a laser beam directed energy deposition technique. Detailed evaluations were conducted on reused powders with two different size distributions, which were compared with their virgin counterparts. Microstructural features and process-induced defects were examined using scanning electron microscopy and X-ray computed tomography. The findings reveal significant alterations in the elemental composition of reused powder, with distinct trends observed for small and large particles. Additionally, powder reuse substantially influenced the formation of process-induced defects and, consequently, the fatigue performance of the components.

Influencing the powder particle transport in high-speed laser melt injection

Using high-speed laser melt injection (HSLMI), it is possible to generate wear-resistant metal matrix composite (MMC) surfaces on tools with great productivity. Since high laser intensities are required for reaching high process speeds, strong interactions can occur between powder particles and the laser beam. In order to reduce the interaction time and gain a better understanding of the role of particle transport in the HSLMI process, trajectories of spherical fused tungsten carbide (SFTC) particles were analyzed using high-speed imaging. The trajectories were divided into a path outside the laser beam and a path inside the laser beam. The identified interaction mechanisms were particle deformations, the formation of agglomerates, and particle disintegration. The volume flow rate of the feeding gas was found to have a decisive influence on the travel time of the particles, whereas the powder feed rate and the working distance of the powder nozzle only had a minor influence. Consequently, an increased volume flow rate led to a significant reduction of interactions between SFTC particles and the laser beam.

Experimental investigation on the surface topographical improvement of selective laser melted SS316L using abrasive flow finishing

Selective laser melting (SLM) offers a precise fabrication of intricate geometries that are not achievable with conventional manufacturing processes. However, surface imperfections like adhered powder particles, waviness, and other anomalies impede the intended functional application and demand additional post-processing steps. Abrasive flow finishing (AFF) process is extensively used for enhancing the surface topography of SLM-built parts by reciprocating a viscoelastic polymer abrasive medium. The cost of commercial abrasive media is expensive, needs costlier and heavy equipment, has little tolerability, and releases hazardous gases during its preparation. In this work, a biopolymer-based abrasive media is developed in-house and employed to examine the surface topographical changes of SLM-built SS316L flat features. Compared to commercial abrasive media, the cost of the developed abrasive media is much lower, does not require expensive equipment, and is eco-friendly. The effect of extrusion pressure, number of finishing cycles, and size of the abrasive particles on the percentage change in areal surface roughness (%ΔSa) and waviness (%ΔWa) was studied. From the analysis of variance, irrespective of %ΔSa and %ΔWa, it was found that the number of cycles was the most contributing process parameter, followed by extrusion pressure and abrasive particle size. The optimised process parameters resulted in a maximum %ΔSa and %ΔWa of about 90.1 % and 66.25 %, respectively, from the initial as-built areal surface roughness of 6.6 ± 0.2 μm and areal surface waviness of 7.7 ± 0.4 μm.

A novel approach for enhancing the mechanical behavior of additively manufactured metal matrix composite structures: Preliminary investigation

Additive Manufacturing is a promising technique for expanding the boundaries of Metal Matrix Composites. In this study, Powder Bed Fusion (PBF) technique, employing Electron Beam as the heat source, was used to print Ti6Al4V metal matrix in different geometric shapes with a new approach for MMC fabrication. Yttria Stabilized Zirconia (YSZ) powder was then incorporated into these pattern shapes, compacted, and sintered to bind the powder particles together. The findings showed that successful sintering was achieved, resulting in the formation of a flexible interface region, with the circular design achieving the best interface region among all pattern designs. Regarding the mechanical performance evaluation of the developed Metal Matrix Composites, it was found that the mechanical strength was significantly increased with the hexagonal and circular patterns achieving the best results. Future research should pay more attention to further design development for the metal matrix model to achieve outstanding performance and create a new field for Metal Matrix Composites using the developed method.

Characterization of Taro (Colocasia esculenta) stolon polysaccharide and evaluation of its potential as a tablet binder in the formulation of matrix tablet

This investigation focuses on the extraction, characterization, and evaluation of taro (Colocasia esculenta) stolon polysaccharide (TSP) as a tablet binding agent, which is obtained from edible taro stolon. TSP was subjected to phytochemical screening and characterized by FTIR, DSC, TGA, DTA, XRD, particle size, polydispersity index, zeta potential, rheological behavior, and SEM. The tablets prepared with varying concentrations of TSP (2.5 %, 5 %, 7.5 %, and 10 % w/w) and diclofenac sodium (DS) were evaluated and compared with the same concentrations of gum acacia and PVP K-30. The presence of carbohydrates was confirmed by Molisch's test. The FTIR spectra established the compatibility of the drug with excipients. The SEM images revealed asymmetric and elongated particles of TSP powder. The hydration kinetics study showed matrix hydration and water penetration velocity within the range of 0.602–0.753 g/g and 0.112–0.189 cm/g.h, respectively. The tablets showed drug release of >75 % at 45 min. The release-exponent value above 0.89 indicated a super case II drug transport combining matrix erosion and diffusion. Optimum tablet hardness and very low friability, even at 2.5 % binder concentration, suggested the potential application of the novel TSP as a tablet binder in the formulation of the tablets.

Specific of mechanical alloying of solid-liquid binary system Fe-Ga and effect of different process control agents

Mechanical alloying allows obtaining nonequilibrium structures in various systems, often possessing unique properties, including magnetic ones. Considering the unusual structural features of the magnetostrictive Fe-Ga alloy, this approach may be promising for this system. In this work, extensive experimental studies were carried out aimed at studying the features of mechanical alloying of Fe-Ga. The object of the study was the system Fe-20 wt% Ga in which disordered solid solution α-Fe(Ga) is formed. It was shown that high-intensity milling is an effective tool for mechanical alloying of solid-liquid binary system Fe-Ga, but a serious problem is a low powder recovery, less than 50 %. To solve this problem, various process control agents were tested. Their influence on powder recovery, process kinetics, particle size, carbon contamination, and magnetic properties was studied using a large set of techniques such as XRD, SEM, EDS, VSM, LIBS, and others. It has been shown that, based on a combination of factors, the optimal process control agent for this system is ethanol in an amount of 1 wt%