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In response to an investigation on the paths of changes in the crystallization and radial differences during the forming process of nascent fibers, in this study, we conducted numerical simulation and analyzed the changes in crystallization mechanical parameters and tensile properties through a fluid dynamics two-phase model. The model was based on the melt-spinning method focusing on melt spinning, the environment of POLYFLOW, and the method of joint simulation, coupled with Nakamura crystallization kinetics, including the development of process collaborative parameters, stretch-induced crystallization, viscoelasticity, filament cooling, gravity term, inertia, and air resistance. Finally, for nylon 6 BHS and CN9987 resin spinning, the model successfully predicted the distribution changes in temperature, velocity, strain rate tensor, birefringence, and stress tensor along the axial and radial fibers and obtained the variation pattern of fibers' crystallinity along the entire spinning process under different stretching rates. Furthermore, we also explored the effects of spinning conditions, including inlet flow rate, winding speeds, and the extrusion temperature, on the fibers' crystallization process and obtained the influence rules of different spinning conditions on fiber crystallization. Knowing the paths of changes in mechanical performance can provide important guidance and optimization strategies for the future industrial preparation of high-performance fibers.

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Biodegradable biopolymers such as polylactic acid and polybutylene succinate are sustainable alternatives to traditional petroleum-based plastics. However, the factors affecting their degradation must be characterized in detail to enable successful utilization. Here we compared the extruder dwell time at three different melt-spinning scales and its influence on the degradation of both polymers. The melt temperature was the same for all three processes, but the shear stress and dwell time were key differences, with the latter being the easiest to measure. Accelerated degradation tests, including quick weathering and disintegration, were used to evaluate the influence of dwell time on the structural, mechanical, and thermal properties of the resulting fibers. We found that longer dwell times accelerated degradation. Quick weathering by UV pre-exposure before the disintegration trial, however, had a more significant effect than dwell time, indicating that degradation studies with virgin material in a laboratory-scale setting only show the theoretical behavior of a product in the laboratory. A weathered fiber from an industrial-scale spinning line more accurately predicts the behavior of a product placed on the market before ending up in the environment. This highlights the importance of optimizing process parameters such as the dwell time to adapt the degradability of biopolymers for specific applications and environmental requirements. By gaining a deeper insight into the relationship between manufacturing processes and fiber degradability, products can be adapted to meet suitable performance criteria for different applications.

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Mn-based magnets are known to be a candidate for use as rare-earth-free magnets. In this study, Mn-Ga bulk magnets were successfully produced by hot pressing using the spark plasma sintering method on Mn-Ga powder prepared from rapidly solidified Mn-Ga melt-spun ribbons. When consolidated at 773 K and 873 K, the Mn-Ga bulk magnets had fine grains and exhibited high coercivity values. The origin of the high coercivity of the Mn-Ga bulk magnets was the existence of the D022 phase. The Mn-Ga bulk magnet consolidated at 873 K exhibited the highest coercivity of 6.40 kOe.

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Multi-leaf hollow-profiled fiber is a complex-shaped fiber with a hollow structure with at least three leaves arranged outside. In this work, spinning processes for the preparation of multi-leaf hollow-profiled fiber with complex cross-section patterns were proposed. Initially, the characteristics and preparation methods of multi-leaf hollow-profiled fibers were analyzed, and the key technologies for their preparation were studied. Further, micro-hole spinnerets were designed, and the numerical simulations of melt flow in the spinning channel were performed. Then, the preparation of six-leaf hollow profiled fibers was carried out to study the formation of the cross-sections. Finally, as an extension and application, an experimental verification of the melt spinning parameters' effects on eight-leaf hollow fiber preparation was conducted. From the results of the spinning experiments, it was found that when the volume flow rate of a single hole increased from 2.33 × 10-8 m3/s to 3.33 × 10-8 m3/s, the profile degree of the spun fiber increased from 30.93% to a maximum value of 40.99%. Furthermore, when the cooling speed increased from 0.6 m/s to 1 m/s, the profile degree increased from 29.56% to 41.63%. When the initial blowing height increased from 80 mm to 140 mm, the profile degree decreased from 40.99% to 27.13%. When the spinning temperature increased from 285 °C to 290 °C, the profile degree decreased from 40.99% to 38.56%. However, the winding speed had an insignificant effect on the cross-sectional shape of the spun fibers. Moreover, the spun fibers showed good performance and a natural three-dimensional crimp function.

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Polyester/cotton fabrics with different proportions of Tetron Cotton, TC (35% Cotton/65% PET), and Chief Value Cotton, CVC (60% Cotton/40% PET), were investigated by removing the cotton component under various phosphoric acidic conditions including the use of cellulase enzymes. The remaining polyethylene terephthalate (PET) component was spun using the melt spinning method. Only 85% H3PO4-Enz_TC could be spun into consistent filament fibers. The effects of Acid-Enz TC (obtained from a powder preparation of 85% H3PO4-Enz_TC) at different weight amounts (1, 2, 5, and 10 %wt) blending with WF-rPET powder prepared by white recycled polyester fabric were evaluated for fiber spinnability at different winding speeds of 1000 and 1500 m/min. The results revealed that recycled PET fiber spun by adding Acid-Enz_TC up to 10 %wt gave uniformly distributed filament fibers. A comparative study of the physical, thermal, and mechanical properties also investigated the relationship between the effect of Acid-Enz_TC and the structure of the obtained fibers. Acid-Enz_TC:WF-rPET (5:95) was the optimal ratio. The thermal values were analyzed by DSC and TGA and crystallinity was analyzed by XRD, with mechanical strength closed to 100% WF-rPET. The FTIR analysis of the functional groups showed the removal of cotton from the blended fabrics. Other factors such as the Acid-Enz_TC component in WF-rPET, extraction conditions, purity, thermal, chemical, and exposure experiences also affected the formability and properties of recycled PET made from non-single-component raw materials. This study advanced the understanding of recycling PET from TC fabrics by strategically removing cotton from polyester-cotton blends and then recycling using controlled conditions and processes via the melt spinning method.

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The structure of a material is an important factor in determining its physical properties. Here, we adjust the structure of the Ni50Mn37Ga13 spun ribbons by changing the wheel speed to regulate the exchange bias effect of the material. The characterization results of micromorphology and structure show that as the wheel speed increases, the martensite lath decreases from 200 nm to 50 nm, the structure changed from the NM to a NM and 10M mixed martensitic structure containing mainly NM, then changed to NM and 10M where 10M and NM are approaching. Meanwhile, HE first increased and then decreased as the wheel speed increased. The optimum exchange bias effect (HE = 7.2 kOe) occurs when the wheel speed is 25 m∙s-1, mainly attributed to the enhanced ferromagnetism caused by part of 10M in NM martensite, which enhanced the exchange coupling of ferromagnetism and antiferromagnetism. This work reveals the structural dependence of exchange bias and provides a way to tune the magnitude of the exchange bias of Heusler alloys.

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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.

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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.

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The paper presents the results of tests of rapid solidification (RS) aluminum alloys with the addition of silicon (5%, 11%, and 20%). Casting by melt-spinning on the surface of an intensively cooled copper cylinder allowed to obtain a metallic material in the form of flakes, which were then consolidated in the process of pressing and direct extrusion. The effect of refinement on structural components after rapid solidification was determined. Rapidly solidified AlSi materials are characterized by a comparable size of Si particles, regardless of the silicon content, and the shape of these particles is close to spheroidal. Not only Si particles are fragmented, but also the Al-Si-Fe phase, which also changed its shape from irregular with sharp edges to regular and spherical. The melt-spinning process resulted in a fine-grained structure compared to materials obtained by gravity-casting and extrusion. The influence of the high-temperature compression test on the mechanical properties of rapidly solidified materials was analyzed, and the results were compared with those of gravity-cast materials. An increase in strength properties was found in the case of the AlSi5 RS alloy by 20%, in the case of AlSi11RS by 25%, and in the case of the alloy containing 20% Si by as much as 86% (tensile test). On the basis of the homogeneity of the particle distribution determined by the SEM method, it was found that rapid solidification is an effective method of increasing the strength properties and improving the plastic properties of Al-Si alloys.

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Ultra-fine fibers derived from sea-island fibers have attracted great attention due to their excellent overall performance. However, green and efficient splitting of sea-island fibers is still a challenging task. In this work, thermoplastic polyvinyl alcohol (TPVA) was prepared by the physical blending of plasticizer. The modified TPVA showed a high decomposition temperature (285 °C) and a wide thermoplastic processing window. This made TPVA match well with polyamide 6 (PA6) to form conjugated melts at 250 °C. Corresponding PVA/PA6 sea-island fibers were first reported to realize water-splitting instead of alkali-extraction of "sea" polymers. The effects of sea/island mass ratios and different spinning speeds on the properties of PVA/PA6 sea-island pre-oriented yarn (POY) were investigated. A higher spinning speed enhanced the orientation-induced crystalline behavior of fiber, therefore increasing the tensile strength of fibers. As the increase of spinning speed from 1000 to 1500 m/min, the crystalline degree of corresponding POYs increased from 9.9 to 14.3%. The plasticizer in PVA did not diffuse to the PA matrix during spinning. However, PVA could induce the crystallization of PA6 via interfacial hydrogen bonding. When the spinning speed was 1500 m/min, and PVA/PA6 was 7:3, the tensile strength reached the highest value of 1.67 cN/dtex. The uniform diameters of ultra-fine PA6 fibers (2-5 µm) were obtained by an environment-friendly water-splitting process. The "sea" phase (TPVA) in sea-island fiber could be removed quickly by boiling water treatment in 3 min. This green and energy-saving sea-island fiber splitting technique is of great significance in reducing CO2 emissions during the preparation of super-fine fibers.

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PET knitted fabric was melted and cooled by hot pressing at 250 °C to obtain a compacted sheet. Only white PET fabric (WF_PET) was used to study the recycling process by compression and grinding to powder and then melt spinning at different take-up speeds compared to PET bottle grade (BO_PET). PET knitted fabric had good fiber formability and was better suited for melt spinning of recycled PET (r-PET) fibers than the bottle grade. Thermal and mechanical properties of r-PET fibers improved in terms of crystallinity and tensile strength with increasing take-up speed (500 to 1500 m/min). Fading and color changes from the original fabric were relatively small compared with PET bottle grade. Results indicated that fiber structure and properties can be used as a guideline for improving and developing r-PET fibers from textile waste.

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Manufacturers of technical polymers must increasingly consider the degradability of their products due to the growing public interest in topics such as greenhouse gas emissions and microplastic pollution. Biobased polymers are part of the solution, but they are still more expensive and less well characterized than conventional petrochemical polymers. Therefore, few biobased polymers with technical applications have reached the market. Polylactic acid (PLA) is the most widely-used industrial thermoplastic biopolymer and is mainly found in the areas of packaging and single-use products. It is classed as biodegradable but only breaks down efficiently above the glass transition temperature of ~60 °C, so it persists in the environment. Some commercially available biobased polymers can break down under normal environmental conditions, including polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT) and thermoplastic starch (TPS), but they are used far less than PLA. This article compares polypropylene, a petrochemical polymer and benchmark for technical applications, with the commercially available biobased polymers PBS, PBAT and TPS, all of which are home-compostable. The comparison considers processing (using the same spinning equipment to generate comparable data) and utilization. Draw ratios ranged from 29 to 83, with take-up speeds from 450 to 1000 m/min. PP achieved benchmark tenacities over 50 cN/tex with these settings, while PBS and PBAT achieved over 10cN/tex. By comparing the performance of biopolymers to petrochemical polymers in the same melt-spinning setting, it is easier to decide which polymer to use in a particular application. This study shows the possibility that home-compostable biopolymers are suitable for products with lower mechanical properties. Only spinning the materials on the same machine with the same settings produces comparable data. This research, therefore, fills the niche and provides comparable data. To our knowledge, this report is the first direct comparison of polypropylene and biobased polymers in the same spinning process with the same parameter settings.

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Preparing flame-retardant polyamide 66 (PA66) fibers through melt spinning remains one of the biggest challenges nowadays. In this work, dipentaerythritol (Di-PE), an eco-friendly flame retardant, was blended into PA66 to prepare PA66/Di-PE composites and fibers. It was confirmed that Di-PE could significantly improve the flame-retardant properties of PA66 by blocking the terminal carboxyl groups, which was conducive to the formation of a continuous and compact char layer and the reduced production of combustible gas. The combustion results of the composites showed that the limiting oxygen index (LOI) increased from 23.5% to 29.4%, and underwriter laboratories 94 (UL-94) passed the V-0 grade. The peak of heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) decreased by 47.3%, 47.8%, and 44.8%, respectively, for the PA66/6 wt% Di-PE composite compared to those recorded for pure PA66. More importantly, the PA66/Di-PE composites possessed excellent spinnability. The prepared fibers still had good mechanical properties (tensile strength: 5.7 ± 0.2 cN/dtex), while maintaining good flame-retardant properties (LOI: 28.6%). This study provides an outstanding industrial production strategy for fabricating flame-retardant PA66 plastics and fibers.

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Shape memory alloys, especially ferromagnetic shape memory alloys, are interesting new materials for the manufacturing of stents. Iron-palladium alloys in particular can be used to manufacture self-expanding temporary stents due to their optimum rate of degradation, which is between that of magnesium and pure iron, two metals commonly used in temporary stent research. In order to avoid blood clotting upon the introduction of the stent, they are often coated with anticoagulants. In this study, sulfated pectin, a heparin mimetic, was synthesized in different ways and used as coating on multiple iron-palladium alloys. The static and dynamic prothrombin time (PT) and activated partial thromboplastin time (APTT) of the prepared materials were compared to samples uncoated or coated with polyethylene glycol. While no large differences were observed in the prothrombin time measurements, the activated partial thromboplastin time increased significantly with all alloys coated with sulfated pectin. Aside from that, sulfated pectin synthesized by different methods also caused slight changes in the activated partial thromboplastin time. These findings show that iron-palladium alloys can be coated with anticoagulants to improve their utility as material for temporary stents. Sulfated pectin was characterized by nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopy, and the coated alloys by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX).

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Biodegradable fibers have been widely developed for advanced textile fields, but their practical applications are limited by large plastic deformation. To solve this problem, we developed a solvent-free melt spinning method to prepare poly(butylene succinate)/microcrystalline cellulose (PBS/MCC) composite monofilaments. The high modulus and rigidity of MCC limit PBS plastic deformation and the in-situ formed hydrogen bonds between MCC and amorphous PBS improved MCC dispersion and led to the formation of rigid MCC physical crosslink points. The composite monofilaments with 10-25 wt% of MCC after multi-stage and high-ratio hot stretching showed a double yielding behavior and microelastic response, indicating the permanent deformation resistance of the composite monofilaments under small deformation. Moreover, the addition of MCC improved the biodegradability of the composite monofilaments after 60 days buried in soil. Therefore, our study provides a design strategy of microelastic composite monofilaments for maintaining dimensional stability during use and accelerating degradation during waste.

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Porous fibers have gained significant attention for their lightweight and high porosity properties in applications such as insulation and filtration. However, the challenge remains in the development of cost-effective, high-performance, and industrially viable porous fibers. In this paper, porous fibers were fabricated through the melt spinning of an alkali soluble polyester (COPET)- CaCO3 masterbatch and PET slice. Controlled alkali and acid post-treatment techniques were employed to create porous structures within the fibers. The effects on the morphology, mechanical, thermodynamic, crystallinity, pore size, and thermal stability were investigated. The results indicate that the uniform dispersion of CaCO3 particles within the fiber matrix acts as nucleating agents during the granulation process, improving the thermal resistance and strength of the porous fiber. In addition, the porous fiber prepared by COPET/CaCO3 to PET with an 85/15 ratio and post-treated on 4% NaOH and 3% HCl exhibits a "spongy body" with uniformly small pores, favorable strength (2.71 cN/dtex), and elongation at break (47%).

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Fibers made from biopolymers are one solution for conserving both resources and the environment. However, these fibers currently have limited strengths, which limit their use for textile applications. In this paper, a biopolymer stereocomplex poly(-lactide) (scPLA) formation on a technical scale of high-molecular-weight poly(D-lactide) (PDLA) and poly(L-lactide) (PLLA) is presented. This scPLA material is the basis for further research to develop scPLA yarns in melt spinning with technical strengths for technical application. scPLA is compared with standard and commercially available semi-crystalline PLA for the production of fibers in melt spinning (msPLA) with textile strengths. Differential scanning calorimetry (DSC) gives a degree of crystallization of 59.7% for scPLA and 47.0% for msPLA. X-ray diffraction (XRD) confirms the pure stereocomplex crystal structure for scPLA and semi-crystallinity for msPLA. scPLA and msPLA are also compared regarding their processing properties (rheology) in melt spinning. While complex viscosity of scPLA is much lower compared to msPLA, both materials show similar viscoelastic behavior. Thermal gravimetric analysis (TGA) shows the influence of the molecular weight on the thermal stability, whereas essentially the crystallinity influences the biodegradability of the PLA materials.

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Magnesium-zinc-calcium (Mg-Zn-Ca) alloys as a biomaterial have attracted much attention recently, owing to their excellent biocompatibility, similar mechanical properties to natural bone, and biodegradable properties. Despite the numerous advantages of MgZnCa alloys, the rapid degradation of magnesium proved challenging as the implant in unable to retain its structural integrity for a sufficient duration of time. For metallic glasses, the capability to produce a bulk sample that is sufficiently large for useful applications have been far less successful owing to challenging processing parameters that are required for rapid cooling. In this study, Mg65Zn30Ca5 melt-spun ribbons were produced using melt-spinning followed by spark plasma sintering under high pressure (60 MPa) at different temperatures (130-170 °C) to provide an insight into the consolidation, mechanical, and corrosion behavior. Microstructural interfaces were characterized using scanning electron microscopy while the thermal stability of the amorphous phase was characterized using differential scanning calorimetry and X-ray diffraction. Here, pellets with 10 mm diameter and 10 mm height with a complete amorphous structure were achieved at a sintering temperature of 150 °C with densification as high at ~98%. Sintering at higher temperatures, while achieving higher densification, resulted in the presence of nano-crystallites. The mechanical properties were characterized using microhardness and compression tests. The hardness values of the sintered products were relatively higher to those containing crystallite phases while the ultimate compressive strength increased with increasing sintering temperature. Bio-corrosion properties were characterized via electrochemical testing with PBS as the electrolyte at 37 °C. The corrosion results suggest that the sintered samples have a significantly improved corrosion resistance as compared to as-cast samples. More notably, SPS150 (samples sintered at 150 °C) exhibited the best corrosion resistance (35× compared to as-cast in the context of corrosion current density), owing to its single-phase amorphous nature. This study clearly shows the potential of spark plasma sintering in consolidating amorphous ribbons to near-full density bulk pellets with high corrosion resistance for bio-applications.

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The solidification kinetics of an alloy from its liquid state forms an underlying basis for microstructural engineering, wherein the state of thermodynamic equilibrium associated with the melt-grown crystal and the quenched amorphous solid denotes the two limits for crystallinity in the alloy synthesis. In this study, we report the implication of the crystalline state on the thermal and electrical transport properties of partially substituted Mn(Si1-xAlx)γ by comparing the single crystals melt-grown by the Bridgman method, and polycrystals synthesized from melt spinning (MS) and subsequent spark plasma sintering (SPS). The rapidly solidified alloys exhibited nanocrystalline microstructures in MS ribbons, while melt-grown single crystals displayed characteristics evolution of MnSi striations with limited solubility of Al. It was observed that Al as a p-type dopant enhances the carrier concentration and electrical conductivity, while nanocrystallinity in MS + SPS polycrystals and secondary phases in monocrystals were effective in enhancing the phonon scattering. Maximum zT values of ∼0.54 (±0.05) at 823 K and 0.75 (±0.05) at 873 K were attained for the single crystal (directed perpendicular to the c-axis) and melt-spun polycrystals (along the in-plane direction), respectively. These results present the efficacy of aliovalent Al substitution and demonstrate the critical role of the solidification kinetics in optimizing the carrier concentration and enhancing the phonon scattering in higher manganese silicide crystals for thermoelectric applications.

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The influence of processing on the martensitic transformation and related magnetic properties of the Ni55Fe18Nd2Ga25 ferromagnetic shape memory alloy, as bulk and ribbons prepared by the melt spinning method and subjected to different thermal treatments, is investigated. Structural, calorimetric, and magnetic characterizations are performed. Thermal treatment at 1173 K induces a decrease in both the Curie and the martensitic transformation temperatures, while a treatment at 673 K produces the structural ordering of the ribbons, hence an increase in TC. A maximum value of the magnetic entropy variation of -5.41 J/kgK was recorded at 310 K for the as quenched ribbons. The evaluation of the magnetoresistive effect shows a remarkable value of -13.5% at 275 K on the bulk sample, which is much higher than in the ribbons.