Melt Spinning Research Articles

Advanced characterization of Al–Ni-Sm amorphous alloys with dispersion of round Pb-rich nanoparticles

The development of materials with special microstructures is a continuing theme of research due to their improved physical and mechanical properties. Rapid solidification can lead to amorphous or partially crystalline microstructures, depending on the imposed processing conditions and compositions allowing the production of composite materials. Al–Ni-Sm alloys can be easily obtained in the amorphous state by rapid solidification processing so that composites could be generated depending on the cooling conditions. In this work, new results are shown for Al-based amorphous matrix composites produced during rapid solidification of Al83.5Ni10Sm6.5, Al81.5Ni10Sm6.5Pb2 and Al83.5Ni8Sm6.5Pb2 (atom percent) alloys. Lead (Pb) was added to the amorphous forming composition alloy due to its immiscibility with the main alloying elements. Ribbon samples were obtained by melt spinning technique. Besides the use of ordinary characterization techniques, such as X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), advanced transmission electron microscopy (TEM) was employed to reveal the special microstructure features forming these alloys. A strong influence of the Pb addition on crystallization behavior has been identified. Also, the size and morphology of the nanocrystalline Pb-rich minority phase within the amorphous matrix is examined. These effects were explained based on the immiscibility of Pb with the alloy components.

Effects of thermal cycling on the thermal and magnetic response of Ni–Mn–Sn–Pd alloys

AbstractMagnetic refrigeration is an option to replace conventional refrigeration. There are many studies that analyze materials with magnetocaloric effect during the first cooling-heating cycle, without analyzing the influence of cycling (necessary to check its applicability). In this work, we proceed to analyze the crystallographic structure (X-Ray diffraction) and the thermal (differential scanning calorimetry) and thermomagnetic (PPMS cycles and ZFC–FH–FC scans) response after a hundred thermal cycles of two Heusler alloys, Ni49Mn36Sn14Pd1 and Ni48Mn36Sn14Pd2 (at.%), that have been produced by melt spinning as ribbon flakes. In order to check its stability from cycling, these ferromagnetic alloys have been subjected to a hundred of thermal cycles (heating/cooling to provoke the austenite to martensite reversible transformation. The comparison before and after cycling behavior allow us to state that the reduction of the crystallographic defects favors higher atomic order. Likewise, the thermodynamic parameters (entropy and enthalpy) and the magnetic response have been reduced at about 10–12%.

Powder Manufacturing Techniques: A Review

The growing need for advanced materials has placed a significant emphasis on the production of top-tier metal powders. To fulfill this demand, several established powder production methods have emerged, aimed at delivering high-purity metal powders. This review paper explores the various techniques used in the production of metal powders, addressing their importance in meeting the evolving requirements of modern manufacturing. Keywords: Atomization, Ball Milling, Melt Spinning, Electro-decomposition.

Preparation and characterization of high performance coal tar pitch-based carbon fiber

High performance carbon fiber based on coal tar pitch is a new type of functional material with unique properties, such as light weight, high strength, high modulus, high thermal conductivity, high electrical conductivity and low thermal expansion coefficient. It is a new type of functional material for both military and civilian use. In order to study the preparation of high performance carbon fiber based on coal tar pitch, this article obtained high performance carbon fiber based on coal tar pitch through raw material pretreatment, spinnable asphalt modulation, asphalt melt spinning, non-melting, carbonization, graphitization and other processes, and characterized the performance of spinnable mesocase asphalt and carbon fiber. The results show that high-performance spinnable mesophase pitch can be prepared by three steps raw material refining, hydrogenation modification and thermal polymerization. The mesophase content is 95%, the softening point is 280 °C, and the 3000 m filament can be spun under melt spinning conditions of 375 °C and 0.01 MPa. After graphitization, the coal pitch-based carbon fiber has excellent mechanical properties, small structural defects and a diameter of 12 μm. The tensile strength is 3089 MPa, the elastic modulus is 689 GPa, and the thermal conductivity is 902 w/(m·K).

Self-fluxing amorphous Nickel-based alloys obtained by different techniques. Performance and technological difficulties

Amorphous metal alloys can already be considered advanced structural materials. This structure induces specific properties such as: high mechanical resistance and hardness, high bending ductility, high elastic modulus, superior resistance to corrosion and wear or, depending on the chemical composition, exceptional magnetic properties. The family of self-fluxing alloys based on nickel has multiple applications: NiCrBSi powders are used with remarkable results in obtaining protective layers against corrosion and wear, strips and wires are successfully used as brazing alloys, etc. In this paper it is presented the research carried out for obtaining and characterizing the amorphous NiCrSiB ribbons, through the melt spinning technique and the massive products (bulks) from the same family through mold casting and additive manufacturing using the Selective Laser Melting (SLM) technique

Enhanced stereocomplex crystalline polylactic acids in melt processed enantiomeric bicomponent fiber configurations

The formation of stereocomplex crystalline domains in the bicomponent fiber melt spinning of enantiomeric polylactic acids (PLAs) is systematically explored and enhanced. Here we report a polycrystalline morphology where distinctly different crystalline regions are formed and aligned along the longitudinal direction of the fiber. This approach employs side-by-side and sheath-core bicomponent melt spinning configurations where the two components are the enantiomeric pairs of poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA). We demonstrate the formation of the PLA stereocomplexes at the junction interphase through the melt spinning process which subsequently crystallize into a round fibers with stereocomplex and homogeneous crystal lamella morphologies. The fiber morphologies and crystallinities of the melt processed fiber are substantially different from the solution based bicomponent spinning system reported in the prior literature. Furthermore, the different molecular weight in the PLLA/PDLA pairing are found to be crucial to the structural development and properties of the PLA polycrystalline materials. The solid-state annealing does not change the crystal distribution of the crystalline domains and stereocomplex crystalline state, it just enhances the homo-crystallinity in the peripheral of the bicomponent fibers.

Heterogeneous high-entropy catalyst nanoparticles for oxygen evolution reaction: Impact of oxygen and fluorine introduction

High-entropy catalysts attract rising attention for promoting oxygen evolution reaction (OER) due to the advantages of multiple catalytic active sites, unique lattice distortion effect, interatomic d-band ligand effect, etc. However, it still needs to design new high-entropy catalysts with low cost and high efficiency to meet the requirement of large-scale applications. In this study, AlNiCuCoFeY amorphous alloy ribbon is prepared by melt spinning method. Then, the ribbon is etched in HF solution to form a nanoparticle modified ribbon, whose superficial species are further conversed to high-entropy oxides/Al alloy (HEO/Al alloy) or high-entropy fluorides/Al alloy (HEF/Al alloy) heterogeneous nanoparticles with a diameter of ∼20 nm by subsequent oxidization or fluorination process. Herein, the oxidized metallic elements with high valence state can promote the adsorption of OER. Due to the large surface area, multiple active sites, and the synergistic effect of different species, the HEO/Al alloy or HEF/Al alloy composite only need 293 and 261 mV overpotential to afford 10 mA cm−2 current density. This work discusses the design of high-entropy electrocatalysts and demonstrated a promising route to improve their OER electrocatalytic performance.

Solubility Enhancement of Itraconazole by Centrifugal Melt Spinning Technique

Itraconazole is an antifungal drug with poor water solubility and limited bioavailability, presenting difficulties in achieving effective therapeutic applications. This study aimed to employ centrifugal melt spinning, an innovative method, to improve the solubility of itraconazole. In this process, itraconazole was subjected to centrifugal forces while melting, forming amorphous solid dispersions. Microfibers loaded with 10% w/w itraconazole were prepared through centrifugal melt spinning, employing sucrose as a carrier. ITZ-sucrose microfibers with uniform morphology and an average diameter of 14.27 ± 2.90 μm were successfully fabricated, as evidenced by the scanning electron microscopy results. XRD and DSC measurements confirmed the amorphous nature of the spun microfibers. The solubility of Itraconazole sucrose microfibers was significantly enhanced by 17-fold compared to plain itraconazole. The dissolution experiments demonstrated that sucrose microfibers loaded with ITZ achieved a significant release of 94.96 ± 1.47% within 10 minutes, representing a substantial enhancement compared to plain drugs. The study indicated that utilizing the centrifugal melt spinning technique successfully generated amorphous solid dispersions of itraconazole, leading to a considerable improvement in the drug’s solubility.

Electrochemical Properties of Carbon Nanobeads and Mesophase-Pitch-Based Graphite Fibers as Anodes for Rechargeable Lithium-Ion Batteries

Various strategies have been devised to enhance the specific capacity (over 372 mA h g−1) and the cycle life of pure carbon-based anode materials for lithium-ion batteries (LIBs). Herein, we have prepared carbon nanobeads (CNBs) with inner onion-like carbon layer structures using chemical vapor deposition. Additionally, mesophase-pitch-based graphite fibers (MPGFs) were fabricated via the melt spinning method. MPGFs had a reversible capacity of 328.2 mA h g−1 with a steady Coulombic efficiency after 105 cycles (at 0.05 mA g−1). When cycled at 0.2 A g−1, the CNBs kept a reversible capacity of 586.2 mA h g−1 after 256 cycles with stable Coulombic efficiency. The onion-like carbon layer structures of CNBs were beneficial to the storage of lithium ions. In this work, CNBs were fabricated with inner onion-like carbon layer structures to enhance the electrochemical performance of LIBs.

Preparation and properties of polyetherimide fibers based on the synergistic effect of carbon nanotubes and ionic liquids

AbstractPolyetherimide (PEI) has been widely applied in the form of plastics, films, and foam materials. But PEI fiber is confronted with some challenges, such as high melt viscosity and high spinning temperature during the spinning process, poor mechanical properties because of its amorphous structure. In this study, ionic liquids (ILs) and carbon nanotubes (CNTs) were used to prepare PEI composite fibers (PEI/CNT‐IL) successfully, which were further characterized by scanning electron microscope (SEM), Raman spectra, differential scanning calorimetry, dynamic mechanical analysis, thermalgravimetric analysis, mechanical property, and conductivity measurements. IL showed a plasticizing effect to reduce the processing temperature of PEI and SEM images showed that CNTs were uniformly dispersed in the PEI matrix by the assistance of IL. The synergistic effect of CNT and IL thus improved the tensile strength and antistatic properties of PEI fibers. When the contents of CNT and IL were 0.5 and 1.0 wt%, respectively, the optimal properties were obtained. PEI/CNT‐IL fibers exhibited a maximum tensile strength of 2.0 cN/dtex with the elongation at break being 90%, and the enhanced electrical conductivity of 10−5 S·cm−1, which was increased by 13 orders of magnitude compared to that of pristine PEI fiber.Highlights PEI composite fibers were prepared via melt spinning with the assistance of IL and CNT. IL can effectively disperse CNT and plasticize PEI to reduce the processing temperature. The synergistic effect of CNT and IL has improved the tensile strength and antistatic properties of PEI fibers.

Novel method of mechanical alignment for chopped carbon fiber/high density polyethylene composites: Processing, modeling, and characterization

In this study, we investigated a novel method of mechanical alignment to enhance the tensile properties of chopped carbon fiber (CCF)/high-density polyethylene (HDPE) composites. By utilizing a novel extruder and take-up system based on the melt spinning technique, we successfully controlled the alignment of CCF at various thicknesses using mechanical tension. This facilitated the production of extruded profiles with controlled tensile conditions. Experimental measurements were conducted to evaluate the tensile strength and modulus of the composites. The results demonstrate the effectiveness of the proposed CCF alignment method, which involves adjusting the thickness of the extruded profiles, in controlling the mechanical properties of the composites. As a result, the ultimate tensile strength increased by 50%, and the tensile modulus increased by 130%. Additionally, we developed a numerical model that predicts the tensile modulus based on randomly generated fibers and the Mori-Tanaka model for property estimation. The fiber orientation distribution was influenced by the fiber shape and manufacturing conditions. Scanning electron microscope (SEM) images revealed that the fibers aligned more along the extrusion direction with increased draw ratio. The orientation distribution of the randomly generated fibers varied significantly based on the fiber length and draw ratio, indicating a narrowed distribution range along the extrusion direction with increased fiber length or draw ratio. These findings demonstrate that the proposed CCF alignment method, which involves changing the thickness of the extruded profiles, can effectively control the mechanical properties of the composite.

Microstructure and Tensile Properties of Melt-Spun Filaments of Polybutene-1 and Butene-1/Ethylene Copolymer.

Polybutene-1 with form I crystals exhibits excellent creep resistance and environmental stress crack resistance. The filaments of polybutene-1 and its random copolymer with 4 mol% ethylene co-units were produced via extrusion melt spinning, which are expected to be in form I states and show outstanding mechanical properties. The variances in microstructure, crystallization-melting behavior, and mechanical properties between homopolymer and copolymer filaments were analyzed using SEM, SAXS/WAXD, DSC, and tensile tests. The crystallization of form II and subsequent phase transition into form I finished after the melt-spinning process in the copolymer sample while small amounts of form II crystals remained in homopolymer filaments. Surprisingly, copolymer filaments exhibited higher tensile strength and Young's modulus than homopolymer filaments, while the homopolymer films showed better mechanical properties than copolymer films. The high degree of orientation and long fibrous crystals play a critical role in the superior properties of copolymer filaments. The results indicate that the existence of ethylene increases the chain flexibility and benefits the formation of intercrystalline links during spinning, which contributes to an enhancement of mechanical properties. The structure-property correlation of melt-spun PB-1 filaments provides a reference for the development of polymer fibers with excellent creep resistance.

Effect of magnetic field annealing on magnetic properties and corrosion resistance of MnBi alloy

Herein, MnBi alloys are prepared using melt spinning and magnetic-field annealing techniques, and the effects of magnetic-field annealing on the microstructure, magnetic properties, magnetisation behaviour, and corrosion resistance of MnBi are systematically investigated. The results show that the saturation magnetisation (Ms) of the Mn55Bi45 ribbons increases with increasing magnetic field annealing temperature and time. Annealing above Curie temperature (Tc) enhances the intrinsic coercivity (Hcj) of the MnBi alloy. Moreover, Mn55Bi45 ribbons with a (BH)max of 2.15 MGOe at room temperature are successfully fabricated after annealing at 673 K for 20 min. The first-order reversal curve (FORC) demonstrate that the Mn55Bi45 ribbons after magnetic-field annealing exhibits weaker exchange coupling compared with the Mn55Bi45 ribbons after nonmagnetic-field annealing. Additionally, the corrosion rate of the Mn55Bi45 ribbons after magnetic-field annealing is lower than that of the Mn55Bi45 ribbons after nonmagnetic-field annealing. Finally, the changes in the grain size and content of the MnBi phase are investigated.

Ultra-rapid freezing of Al and Al–Si12: Formation of nanocrystals and metastable solid solutions

We report effects of ultra-rapid melt–freeze cycles on pure aluminum and on aluminum alloy 4047 (which contains ≈12 at. % Si) caused by a series of ≈15 ns-long pulses of 308-nm laser light at a fluence of around 3 J cm−2. This process achieves a calculated cooling rate of about 109 K s−1, which is much faster than splat cooling or melt spinning. The focus here is on the reduction in the lattice parameters of the resulting crystals. In pure aluminum, this reduction is caused by the formation of nanocrystals, whose sizes are determined by the magnitude of the change in the lattice parameter. However, for the alloy, previous investigators have also found a comparable reduction in the lattice parameter but attributed it, instead, to the formation of metastable solutions of Si in Al. We find that the effect in the Al–Si alloy is caused by an unknown combination of size and composition dependence, but it is possible that there is no size dependence in the alloy.

Improvement of soft magnetic properties of a Nanoperm-type Fe-Hf-B nanocrystalline alloy upon surface crystallization inhibition by Cu addition

Nanoperm-type alloy ribbons suffer from surface crystallization during melt spinning, which degrades their magnetic properties after annealing and limits their commercial application. Here, we investigate the effects of Cu addition on the structure and magnetic properties of a surface-textured Fe87-xHf5B8Cux alloy. Adding Cu (1 ≤ x ≤ 2) removes the surface coarse grains in the free surface of the melt-spun precursor, while induces the precipitation of large amounts of the α-Fe nanoparticles with ∼3 nm in size, which contributes a homogeneous ultrafine structure and improved magnetic softness after annealing. The grain size, coercivity, saturation magnetic flux density, and effective permeability at 1 kHz of the Fe86Hf5B8Cu1 nanocrystalline alloy are 13.3 nm, 6.6 A/m, 1.68 T, and 23000, respectively, whereas these are 16.0 nm, 16.8 A/m, 1.70 T, and 15000, respectively, for the Fe87Hf5B8 alloy. The Cu-improved effect is mainly attributed that Cu induces heterogeneous nucleation of the α-Fe phase to strengthen the competitive growth among grains.

A Study of R2T14B (R = Y, Nd, Gd, Ho, T = Fe, Co) Hard Magnetic Materials via Magnetometry and Atomic Force Microscopy

Magnetometry and atomic force microscopy (AFM) were used to study the magnetic and structural properties of the R–Fe–B-type (R = Y, Nd, Gd, Ho) alloys. The alloys were synthesized by means of induction melting. The nanocrystalline state of the R–Fe–B-type alloys was reached, mainly, by melt spinning (MS). A multistage treatment of R–Fe–B-type alloys, which included severe plastic deformation of melt-quenched ribbons and subsequent heat treatment, was also used. The surface morphology of samples was studied in detail to interpret the observed magnetic hysteresis loops of the samples. It was found that the type of rare earth ion and treatment methods had the most important influence on the microstructure and magnetic properties.

The Antifungal Fibers of Polyamide 12 Containing Silver and Metal Oxides.

The textile market is a vast industry that utilizes antimicrobial polymeric materials, including various types of fabrics, for medical and personal protection applications. Therefore, this study focused on examining four types of antimicrobial fillers, namely, metal oxides (zinc, titanium, copper) and nanosilver, as fillers in Polyamide 12 fibers. These fillers can be applied in the knitting or weaving processes to obtain woven polymeric fabrics for medical applications. The production of the fibers in this study involved a two-step approach: twin-screw extrusion and melt spinning. The resulting fibers were then characterized for their thermal properties (TGA, DSC), mechanical performance (tensile test, DMA), and antifungal activity. The findings of the study indicated that all of the fibers modified with fillers kill Candida albicans. However, the fibers containing a combination of metal oxides and silver showed significantly higher antifungal activity (reduction rate % R = 86) compared to the fibers with only a mixture of metal oxides (% R = 21). Furthermore, the inclusion of metal oxides and nanosilver in the Polyamide 12 matrix hindered the formation of the crystal phase and decreased slightly the thermal stability and mechanical properties, especially for the composites with nanosilver. It was attributed to their worse dispersion and the presence of agglomerates.

Structure and physical properties of Mg-based metallic glasses prepared by a melt spinning technique

Structure and physical properties of Mg-based metallic glasses prepared by a melt spinning technique

Modified polyamide fibers with low surface friction coefficient to reduce microplastics emission during domestic laundry

The widespread presence of microplastics has become a serious threat to humans and ecological environments because they carry many pollutants and can be easily ingested by aquatic organisms. Fibrous microplastics (FMPs) released from synthetic fiber garments during domestic laundry are a major source of contamination. Herein, we report a facile FMPs mitigation strategy for polyamide 6 (PA6) fibers by incorporating environmentally friendly polydimethylsiloxane (PDMS) during melt spinning. The obtained PA6/PDMS fibers showed a lower friction coefficient than the pure PA6 fibers. Surface morphology, tribology, and washing characterizations verified that a 60% reduction in FMPs shedding was achieved by reducing the friction. In addition, the low-surface-friction PA6/PDMS fabrics with high hydrophobicity exhibited improved waterproof and anti-stain behaviors. It is important to note that none of the essential properties, such as surface structure, dyeing and printing of the fabrics were compromised after PDMS blending. This study provides a green and scalable route for mitigating laundry microfibers using a fiber domain design.

Nanocomposite Nanofibers of Graphene—Fundamentals and Systematic Developments

Research on polymer nanocomposite nanofibers has seen remarkable growth over the past several years. One of the main driving forces for this progress is the increasing applicability of polymer nanocomposite nanofibers for technological applications. This review basically aims to present the current state of manufacturing polymer/graphene nanofiber nanocomposites, using appropriate techniques. Consequently, various conducting and thermoplastic polymers have been processed with graphene nano-reinforcement to fabricate the nanocomposite nanofibers. Moreover, numerous methods have been adopted for the fabrication of polymer/graphene nanocomposites and nanofibers including interfacial polymerization, phase separation, freeze drying, template synthesis, drawing techniques, etc. For the formation of polymer/graphene nanocomposite nanofibers, electrospinning can be preferable due to various advantages such as the need for simple equipment, control over morphology, and superior properties of the obtained material. The techniques such as solution processing, melt spinning, and spin coating have also been used to manufacture nanofibers. Here, the choice of manufacturing techniques and parameters affects the final nanofiber morphology, texture, and properties. The manufactured nanocomposite nanofibers have been examined for exceptional structural, microstructure, thermal, and other physical properties. Moreover, the properties of polymer/graphene nanofiber rely on the graphene content, dispersion, and matrix–nanofiller interactions. The potential of polymer/graphene nanocomposite nanofibers has been investigated for radiation shielding, supercapacitors, membranes, and the biomedical field. Hence, this review explains the literature-driven significance of incorporating graphene in polymeric nanofibers. Conclusively, most of the studies focused on the electrospinning technique to design polymer/graphene nanofibers. Future research in this field may lead to advanced innovations in the design and technical applications of nanocomposite nanofibers. To the best of our knowledge, research reports are available on this topic; however, the stated literature is not in a compiled and updated form. Therefore, field researchers may encounter challenges in achieving future advancements in the area of graphene-based nanocomposite nanofibers without first consulting the recent literature, such as an assembled review, to gain necessary insights, etc. Consequently, this state-of-the-art review explores the manufacturing, properties, and potential of polymer/graphene nanocomposite nanofibers.