(Nd(1-x)Cex)(12)Fe(77)Ti5B6(x=0,0.2,0.3,0.4,0.6,0.8)alloys were prepared by melt-spinning and annealing techniques.The phase constitutions,microstructures and magnetic properties were investigated by powder X-ray diff...(Nd(1-x)Cex)(12)Fe(77)Ti5B6(x=0,0.2,0.3,0.4,0.6,0.8)alloys were prepared by melt-spinning and annealing techniques.The phase constitutions,microstructures and magnetic properties were investigated by powder X-ray diffraction(XRD),a differential scanning calorimeter(DSC),a vibrating sample magnetometer(VSM)and a transmission electron microscope(TEM).It is found that with the increase of Ce content,the coercivity of the(Nd(1-x)Cex)(12)Fe(77)Ti5B6 alloys reaches maximum first and then decreases.The maximum coercivity reaches 18.5 kOe obtained in the sample of 20%Ce substituted which is 34%higher than the Ce-free sample.TEM results reveal that the micro structure refinement effect is responsible for the coercivity improvement.This phenomenon implies that in some cases,Ce and Ti co-doping is more beneficial to improving of the coercivity than Ti single doping in Nd-Fe-B alloys.With further Ce addition,magnetic properties deteriorate due to the formation of CeFe2 and TbCu7-type phases.展开更多
In this study, the effect of wheel speed and mischmetal（MM） content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal compositio...In this study, the effect of wheel speed and mischmetal（MM） content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal composition of the alloy ingots is MM;Fe;B;with x varying from 9 to 15 in steps of 2. Experimental results show the overall magnetic properties of the ribbons.Analysis of the results shows that the magnetic properties first improve and then degrade with the wheel speed and MM content increasing. Increase in MM content leads to better formation of crystal texture in the ribbons, indicating that the a-Fe phase might undermine the formation of crystal texture. Magnetic properties results show that the coercivity of the ribbons rises with an appropriate increase in both MM content and wheel speed during melt-spun process. The strongest magnetic properties of the ribbons(remanence of M;= 0.72 T, intrinsic coercivity of H;= 352.58 kA·m;, and maximum energy product of（BH）;=72.14 kJ·m;) are obtained for compositions where x = 13 and a wheel speed of v = 20 m·s;.展开更多
Generally, ring spun yarns are manufactured from roving which is produced by roving frame. In this paper, an experiment has been done producing ring spun cotton yarn directly from finisher drawn sliver eliminatin...Generally, ring spun yarns are manufactured from roving which is produced by roving frame. In this paper, an experiment has been done producing ring spun cotton yarn directly from finisher drawn sliver eliminating the roving frame. Total 3 types of yarn with the various linear density of 8 Ne, 10 Ne & 12 Ne were produced using a roving frame and without using a roving frame. In the next step, physical and mechanical properties of those yarns including unevenness, imperfections, hairiness & tenacity were investigated. The result showed that ring spun cotton yarns produced from sliver exhibited inferior physical and mechanical properties compared with samples from the conventional ring spinning system.展开更多
The effects of Ni addition on the liquid phase separation and giant magnetoresi stance (GMR) of Cu Co alloys were discussed. The results reveal that Ni additio n can partially restrain the liquid phase separation of C...The effects of Ni addition on the liquid phase separation and giant magnetoresi stance (GMR) of Cu Co alloys were discussed. The results reveal that Ni additio n can partially restrain the liquid phase separation of Cu Co alloys, resultin g in a decrease of volume fraction for the Co rich particles separated from the liquid phase and in refined microstructures. The composition analyses indicate t hat Ni is dissolved in both the Co rich and the Cu rich phases, but Ni content in the Co rich phase is much higher than that in the Cu matrix. At the same ti me, Ni addition enhance the solubility between Cu and Co, especially Cu in Co s olid solution. Ni alloying into Cu Co alloys can fully prevent the liquid phase separation during melt spinning, which is very beneficial to improve GMR of Cu Co alloys.展开更多
Effect of multiple alloying elements (Ga, Nb, Zr, Hf and Pr) on microstructure and magnetic properties of nanocomposite Nd 9- x Pr x Fe 86.5- y-z-m-n Ga y Nb z Zr m Hf n B 4.5 ( ...Effect of multiple alloying elements (Ga, Nb, Zr, Hf and Pr) on microstructure and magnetic properties of nanocomposite Nd 9- x Pr x Fe 86.5- y-z-m-n Ga y Nb z Zr m Hf n B 4.5 ( x =0, 2 25; y, z, m, n =0.5, 1.0) ribbons was investigated by a L 16 (2 15 ) orthogonal experiment. The results show that the addition of multiple alloying elements can effectively reduce the grain size of Nd 2Fe 14 B and α Fe phases and promote amorphous phase to occur at low wheel speed. No inhomogeneous growth of grains was found in annealed ribbons, but a large amount of additives would results in irregularity of Nd 2Fe 14 B and α Fe grains. On the other hand, addition of multiple alloying elements has complex effects on magnetic properties due to interactions between alloying elements. When the content of Nb is 0.5%, increasing the content of Pr and Ga and decreasing the content of Zr and Hf can improve the magnetic properties effectively. The optimum magnetic properties were obtained in Nd 2.25 Pr 6.75 Fe 84.5 Ga 1.5 Nb 0.5 B 4.5 ribbons spun at 15 m·s -1 with J r=1.053 T, i H c=530.9 kA·m -1 ,( BH ) max =124 kJ·m -3 .展开更多
Compounds with the composition SmFex（x=3–8） were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 ℃. The crystal structures of the as-quenched and as a...Compounds with the composition SmFex（x=3–8） were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 ℃. The crystal structures of the as-quenched and as annealed powders were investigated by XRD methods with following Rietveld analysis. The glass forming ability could be enhanced by the increase of Sm content to x≤5.Metastable Sm5Fe17-type structure existed when 3≤x≤5 and temperature was lower than 800 ℃. SmFe2-type structure could be stable up to 1000 ℃ when x〉3 and temperature was under 800 ℃. The content of SmFe2-type decreased with the increase of x value and increased with temperature lower than 800 ℃, from which SmFe2-type started to bring the transition to SmFe3-type. As for Sm5Fe17-type compounds with x=3.4, the highest coercivity of 33.6 kOe could be obtained under a velocity of 30 m/s and heat treated under 700 ℃×1h.展开更多
The lower strength of friction spun yarns has became a key problem that hinder the develop-ment of friction spinning,especially in high speeds and fine yarns.In this paper a project aimed atincreasing the strength of ...The lower strength of friction spun yarns has became a key problem that hinder the develop-ment of friction spinning,especially in high speeds and fine yarns.In this paper a project aimed atincreasing the strength of friction spun yarns by using a false twist process has been made.In re-ported experiment false twist was inserted into the yarn which has been formed on a friction spin-ning machine,so that it made the yarn untwist at first,then regain the twist.In the meantime draftwas applied to generate more tension than that which had been experienced during yarn formationon the friction spinning machine.It made the yarn reforming and the loosely bound fibres in thefriction spun yarn formed due to extremely low tension on the friction spinning machine becametighter.Results indicate that with the proper draft,tension and false twist the tenacity of processedyarn will increase more than 10%.This project is an attempt to discover whether improvements can be made and whether it isworth pursuing research into modifications of yarn structure.The results imply that if the yarntension can be raised during yarn formation on the friction spinning machine or a chance is offeredto the yarn to reform after the yarn formation the yarn tenacity will be increased obviously.展开更多
In order to improve the quality of yarn,a research was carried out at ring spinning.A modifiedtraveller has been used to reduce the yarn hairiness vastly.According to the statistical analysis ofthe data,it was found t...In order to improve the quality of yarn,a research was carried out at ring spinning.A modifiedtraveller has been used to reduce the yarn hairiness vastly.According to the statistical analysis ofthe data,it was found that the geometrical shape of travellers is the key factor affecting the yarnhairiness at ring spinning.展开更多
A model was deveIoped to investigate impregnation behavior of thermoplastic resin into filament bundle based on Darcy's law. Consolidation processes of unidirectional laminate were performed to evaluate the validi...A model was deveIoped to investigate impregnation behavior of thermoplastic resin into filament bundle based on Darcy's law. Consolidation processes of unidirectional laminate were performed to evaluate the validity of the model. Friction spun core yarns were used in the experiments with polypropylene fiber sheath and glass filament core. The processing conditions, such as temperature and pressure, and filament parameters were taken into consideration. A good agreement was found between theoretical prediction and experiment data.展开更多
Friction spun core yarn has two components: filament core and staple fiber sheath. Under axial rubbing action, the failure mode of the core yarn is the stripping of the sheath from the core. This paper introduces a me...Friction spun core yarn has two components: filament core and staple fiber sheath. Under axial rubbing action, the failure mode of the core yarn is the stripping of the sheath from the core. This paper introduces a method to test the anti - stripping property of the core yarn. With a modified Universal Testing Machine, the stripping resistance of friction spun core yarn can be continuously measured. Some factors Influencing the measurements are discussed in detail. The testing results are compared with those from a Y731 Yarn Abrasion Tester and fur - ther confirmed by weaving practice.展开更多
In this paper, fibrillation properties of solvent - spun cellulose fiber and some influencing factors are analyzed based on the experiment results. It is pointed out that special textile styles and aesthetic appearanc...In this paper, fibrillation properties of solvent - spun cellulose fiber and some influencing factors are analyzed based on the experiment results. It is pointed out that special textile styles and aesthetic appearance could be obtained by controlling the fibrillation.展开更多
Highly textured Heusler alloy Mn_（46）Ni_（42）Sn_（11）Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic tr...Highly textured Heusler alloy Mn_（46）Ni_（42）Sn_（11）Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transformation（MT）, and magnetoresistance（MR） properties were investigated. The MR in the annealed ribbon was assessed by the magnetic field direction perpendicular to the ribbon surface with the magnetic field up to 30 k Oe. The large negative value of 25% for MR was obtained at 244 K. The exchange bias（EB） effects of the as-spun and annealed ribbons were investigated. After annealing, the EB effects have been improved by about 25 Oe at the temperature of 50 K. The magnetizations have increased approximately by 10% more than the as-spun ribbon.展开更多
Amorphous(Fe40Ni40B19Cu1)100-xNbx(x=1,3,5,7)ribbons are prepared by using the melt-spinning method.We find that the glass forming ability(GFA)of the as-melt spun ribbons is significantly improved by adding Nb element....Amorphous(Fe40Ni40B19Cu1)100-xNbx(x=1,3,5,7)ribbons are prepared by using the melt-spinning method.We find that the glass forming ability(GFA)of the as-melt spun ribbons is significantly improved by adding Nb element.In addition,the thermal stability evaluated in steps of△T=Tx2-Tx1 effectively increases from 16 K to 75 K with Nb content increasing.The as-melt spun(Fe40Ni40B19Cu1)97 Nb3 ribbon exhibits a lowest coercivity of 2 A/m and relatively large saturation magnetization of 103.7 A·m^2/kg and thus it can be further treated by being annealed at 809 K.The crystallization behavior is confirmed to be determined by two individual crystallization processes corresponding to the precipitation of(Fe,Ni)23 B6 phase andγ-(Fe,Ni)phase.With increasing annealing time,the single(Fe,Ni)23B6 phase can be transformed into a mixture of(Fe,Ni)23B6 andγ-(Fe,Ni)phase,and the grain size ofγ-(Fe,Ni)phase increases from 5 nm to 80 nm while the grain size of(Fe,Ni)23B6 remains almost unchanged.Finally,we find that the grain growth in each of(Fe,Ni)23B6 andγ-(Fe,Ni)deteriorates the overall magnetic properties.展开更多
It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio use...It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio used.Ten years ago,PE shish-kebabs grown from dilute solutionwere proved to have extended chain backbone which causes the raising of its melting point.These crystals were found to have a triclinic crystal phase,This study shows a different result forgel spun ultra high drawn PE fiber.The unit cell remains orthorhombic even if the draw ratioreaches 50;as the draw ratio increases,the length in a and b axes are shortened while that in c ax-is changes quite insignificantly.When the draw ratio is over 10,two endothermic melting peakscan be seen in the DSC curves with corresponding peak temperature of 136.7-145.3℃.The lat-ter peak is attributed to the amount of extended chain crystal.展开更多
A new concept of spinning-open-end jet-spinning, which combines the advantages of the false twist jet spinning and open end winning, was proposed, and a device was designed to practice this concept. The property of th...A new concept of spinning-open-end jet-spinning, which combines the advantages of the false twist jet spinning and open end winning, was proposed, and a device was designed to practice this concept. The property of thc open-end jet spun yarn was measured and discussed in comparison with that of some other spun yarns.展开更多
This paper described the physical behaviour of three types of denim cloths produced from rotor yarn, ring yarn and modified rotor yarn (prepared by adding conventional twist to rotor yarn) respectively. Experimental w...This paper described the physical behaviour of three types of denim cloths produced from rotor yarn, ring yarn and modified rotor yarn (prepared by adding conventional twist to rotor yarn) respectively. Experimental work showed that denim cloth produced from the modified rotor yarn has superior properties over conventional rotor yarn in terms of surface texture and appearance,tearing strength and resistance to abrasion.展开更多
Consolidation of thermoplastic unidirectional(UD)lami-nate with friction spun core yarns was investigated,espe-cially the characterization of filament bundles in consoli-dation was analyzed.The results showed that the...Consolidation of thermoplastic unidirectional(UD)lami-nate with friction spun core yarns was investigated,espe-cially the characterization of filament bundles in consoli-dation was analyzed.The results showed that the bundleeffect was affected considerably by processing conditions(applied pressure and processing time).The boundaryof the bundles was disappeared under suitable processingconditions and finally an even fiber/resin distributioncould be attained.In consolidation,filament bundlesgetting close each other and resin flowing into the bundl-es occurred simultaneously,and eventually the bundleswere fully impregnated by the resin.Fiber packing den-sity in UD-laminate was the same as that of frictionspun core yarn(55%-65% in volume)and was not af-fected significantly by processing conditions under thecurrent experimental conditions.展开更多
The rotor spun yarn(OE yarn),twist of which is calledlayering twist,was added a few involving twist,and itsstructure and properties were measured.The experimen-tal results have shown that the morphological structure o...The rotor spun yarn(OE yarn),twist of which is calledlayering twist,was added a few involving twist,and itsstructure and properties were measured.The experimen-tal results have shown that the morphological structure ofthe rotor spun yarn with modified twist was changed andits tensile properties and abrasion resistance were im-proved.展开更多
基金Project supported by the National Key Research and Development Program of China(2016YFB0700902)
文摘(Nd(1-x)Cex)(12)Fe(77)Ti5B6(x=0,0.2,0.3,0.4,0.6,0.8)alloys were prepared by melt-spinning and annealing techniques.The phase constitutions,microstructures and magnetic properties were investigated by powder X-ray diffraction(XRD),a differential scanning calorimeter(DSC),a vibrating sample magnetometer(VSM)and a transmission electron microscope(TEM).It is found that with the increase of Ce content,the coercivity of the(Nd(1-x)Cex)(12)Fe(77)Ti5B6 alloys reaches maximum first and then decreases.The maximum coercivity reaches 18.5 kOe obtained in the sample of 20%Ce substituted which is 34%higher than the Ce-free sample.TEM results reveal that the micro structure refinement effect is responsible for the coercivity improvement.This phenomenon implies that in some cases,Ce and Ti co-doping is more beneficial to improving of the coercivity than Ti single doping in Nd-Fe-B alloys.With further Ce addition,magnetic properties deteriorate due to the formation of CeFe2 and TbCu7-type phases.
基金financially supported by the National Natural Science Foundation of China (Nos. 51461033, 51571126, 51541105, and 11547032)the Inner Mongolia Innovative Research Team (No. 3400102)+3 种基金the Inner Mongolia Science Foundation (No. 2013MS0110)the Provincial Major Science and Technology Project of Inner Mongolia (No. 2009J1006)the Baotou Major Research Project Special for Rare Earth (No. 2012R1006)the Inner Mongolia University of Science and Technology Innovation Fund
文摘In this study, the effect of wheel speed and mischmetal（MM） content on the magnetic properties of MMFeB ribbons was investigated. The samples were prepared via direct solidification technique. The nominal composition of the alloy ingots is MM;Fe;B;with x varying from 9 to 15 in steps of 2. Experimental results show the overall magnetic properties of the ribbons.Analysis of the results shows that the magnetic properties first improve and then degrade with the wheel speed and MM content increasing. Increase in MM content leads to better formation of crystal texture in the ribbons, indicating that the a-Fe phase might undermine the formation of crystal texture. Magnetic properties results show that the coercivity of the ribbons rises with an appropriate increase in both MM content and wheel speed during melt-spun process. The strongest magnetic properties of the ribbons(remanence of M;= 0.72 T, intrinsic coercivity of H;= 352.58 kA·m;, and maximum energy product of（BH）;=72.14 kJ·m;) are obtained for compositions where x = 13 and a wheel speed of v = 20 m·s;.
文摘Generally, ring spun yarns are manufactured from roving which is produced by roving frame. In this paper, an experiment has been done producing ring spun cotton yarn directly from finisher drawn sliver eliminating the roving frame. Total 3 types of yarn with the various linear density of 8 Ne, 10 Ne & 12 Ne were produced using a roving frame and without using a roving frame. In the next step, physical and mechanical properties of those yarns including unevenness, imperfections, hairiness & tenacity were investigated. The result showed that ring spun cotton yarns produced from sliver exhibited inferior physical and mechanical properties compared with samples from the conventional ring spinning system.
文摘The effects of Ni addition on the liquid phase separation and giant magnetoresi stance (GMR) of Cu Co alloys were discussed. The results reveal that Ni additio n can partially restrain the liquid phase separation of Cu Co alloys, resultin g in a decrease of volume fraction for the Co rich particles separated from the liquid phase and in refined microstructures. The composition analyses indicate t hat Ni is dissolved in both the Co rich and the Cu rich phases, but Ni content in the Co rich phase is much higher than that in the Cu matrix. At the same ti me, Ni addition enhance the solubility between Cu and Co, especially Cu in Co s olid solution. Ni alloying into Cu Co alloys can fully prevent the liquid phase separation during melt spinning, which is very beneficial to improve GMR of Cu Co alloys.
文摘Effect of multiple alloying elements (Ga, Nb, Zr, Hf and Pr) on microstructure and magnetic properties of nanocomposite Nd 9- x Pr x Fe 86.5- y-z-m-n Ga y Nb z Zr m Hf n B 4.5 ( x =0, 2 25; y, z, m, n =0.5, 1.0) ribbons was investigated by a L 16 (2 15 ) orthogonal experiment. The results show that the addition of multiple alloying elements can effectively reduce the grain size of Nd 2Fe 14 B and α Fe phases and promote amorphous phase to occur at low wheel speed. No inhomogeneous growth of grains was found in annealed ribbons, but a large amount of additives would results in irregularity of Nd 2Fe 14 B and α Fe grains. On the other hand, addition of multiple alloying elements has complex effects on magnetic properties due to interactions between alloying elements. When the content of Nb is 0.5%, increasing the content of Pr and Ga and decreasing the content of Zr and Hf can improve the magnetic properties effectively. The optimum magnetic properties were obtained in Nd 2.25 Pr 6.75 Fe 84.5 Ga 1.5 Nb 0.5 B 4.5 ribbons spun at 15 m·s -1 with J r=1.053 T, i H c=530.9 kA·m -1 ,( BH ) max =124 kJ·m -3 .
基金supported by the National High Technology Research and Development Program of China(863 Program)(2011AA03A402)
文摘Compounds with the composition SmFex（x=3–8） were prepared by melt spun method at a velocity of 40 m/s and subsequent annealing at temperature between 600–1000 ℃. The crystal structures of the as-quenched and as annealed powders were investigated by XRD methods with following Rietveld analysis. The glass forming ability could be enhanced by the increase of Sm content to x≤5.Metastable Sm5Fe17-type structure existed when 3≤x≤5 and temperature was lower than 800 ℃. SmFe2-type structure could be stable up to 1000 ℃ when x〉3 and temperature was under 800 ℃. The content of SmFe2-type decreased with the increase of x value and increased with temperature lower than 800 ℃, from which SmFe2-type started to bring the transition to SmFe3-type. As for Sm5Fe17-type compounds with x=3.4, the highest coercivity of 33.6 kOe could be obtained under a velocity of 30 m/s and heat treated under 700 ℃×1h.
文摘The lower strength of friction spun yarns has became a key problem that hinder the develop-ment of friction spinning,especially in high speeds and fine yarns.In this paper a project aimed atincreasing the strength of friction spun yarns by using a false twist process has been made.In re-ported experiment false twist was inserted into the yarn which has been formed on a friction spin-ning machine,so that it made the yarn untwist at first,then regain the twist.In the meantime draftwas applied to generate more tension than that which had been experienced during yarn formationon the friction spinning machine.It made the yarn reforming and the loosely bound fibres in thefriction spun yarn formed due to extremely low tension on the friction spinning machine becametighter.Results indicate that with the proper draft,tension and false twist the tenacity of processedyarn will increase more than 10%.This project is an attempt to discover whether improvements can be made and whether it isworth pursuing research into modifications of yarn structure.The results imply that if the yarntension can be raised during yarn formation on the friction spinning machine or a chance is offeredto the yarn to reform after the yarn formation the yarn tenacity will be increased obviously.
文摘In order to improve the quality of yarn,a research was carried out at ring spinning.A modifiedtraveller has been used to reduce the yarn hairiness vastly.According to the statistical analysis ofthe data,it was found that the geometrical shape of travellers is the key factor affecting the yarnhairiness at ring spinning.
基金Funded by the Research Fund for the Doctoral Program of High Education
文摘A model was deveIoped to investigate impregnation behavior of thermoplastic resin into filament bundle based on Darcy's law. Consolidation processes of unidirectional laminate were performed to evaluate the validity of the model. Friction spun core yarns were used in the experiments with polypropylene fiber sheath and glass filament core. The processing conditions, such as temperature and pressure, and filament parameters were taken into consideration. A good agreement was found between theoretical prediction and experiment data.
文摘Friction spun core yarn has two components: filament core and staple fiber sheath. Under axial rubbing action, the failure mode of the core yarn is the stripping of the sheath from the core. This paper introduces a method to test the anti - stripping property of the core yarn. With a modified Universal Testing Machine, the stripping resistance of friction spun core yarn can be continuously measured. Some factors Influencing the measurements are discussed in detail. The testing results are compared with those from a Y731 Yarn Abrasion Tester and fur - ther confirmed by weaving practice.
文摘In this paper, fibrillation properties of solvent - spun cellulose fiber and some influencing factors are analyzed based on the experiment results. It is pointed out that special textile styles and aesthetic appearance could be obtained by controlling the fibrillation.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB722801)the Postdoctoral Science Foundation of China(Grant No.2015M571285)+3 种基金the National Natural Science Foundation of China(Grant No.51401140)the Postdoctoral Research Station Foundation of Taiyuan University of Science and Technology,China(Grant Nos.20142014,20152041,and 20151082)the Natural Science Foundation of Shanxi Province,China(Grants Nos.2015021019,2015091011,and 2015081011)the Key Team of Scientific and Technological Innovation of Shanxi Province,China(Grant No.2013131009)
文摘Highly textured Heusler alloy Mn_（46）Ni_（42）Sn_（11）Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transformation（MT）, and magnetoresistance（MR） properties were investigated. The MR in the annealed ribbon was assessed by the magnetic field direction perpendicular to the ribbon surface with the magnetic field up to 30 k Oe. The large negative value of 25% for MR was obtained at 244 K. The exchange bias（EB） effects of the as-spun and annealed ribbons were investigated. After annealing, the EB effects have been improved by about 25 Oe at the temperature of 50 K. The magnetizations have increased approximately by 10% more than the as-spun ribbon.
基金Project supported by the National Natural Science Foundation of China(Grant No.51731003)the Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi Province,China(2014)+2 种基金the “131” Leading Talents Project of Higher Education Institutions in Shanxi Province,China(2015)the Overseas Students Science and Technology Activities Project Merit Funding,China(2016)the Fund for Shanxi Key Subjects Construction
文摘Amorphous(Fe40Ni40B19Cu1)100-xNbx(x=1,3,5,7)ribbons are prepared by using the melt-spinning method.We find that the glass forming ability(GFA)of the as-melt spun ribbons is significantly improved by adding Nb element.In addition,the thermal stability evaluated in steps of△T=Tx2-Tx1 effectively increases from 16 K to 75 K with Nb content increasing.The as-melt spun(Fe40Ni40B19Cu1)97 Nb3 ribbon exhibits a lowest coercivity of 2 A/m and relatively large saturation magnetization of 103.7 A·m^2/kg and thus it can be further treated by being annealed at 809 K.The crystallization behavior is confirmed to be determined by two individual crystallization processes corresponding to the precipitation of(Fe,Ni)23 B6 phase andγ-(Fe,Ni)phase.With increasing annealing time,the single(Fe,Ni)23B6 phase can be transformed into a mixture of(Fe,Ni)23B6 andγ-(Fe,Ni)phase,and the grain size ofγ-(Fe,Ni)phase increases from 5 nm to 80 nm while the grain size of(Fe,Ni)23B6 remains almost unchanged.Finally,we find that the grain growth in each of(Fe,Ni)23B6 andγ-(Fe,Ni)deteriorates the overall magnetic properties.
基金This project is supported by National Science Foundation of China
文摘It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio used.Ten years ago,PE shish-kebabs grown from dilute solutionwere proved to have extended chain backbone which causes the raising of its melting point.These crystals were found to have a triclinic crystal phase,This study shows a different result forgel spun ultra high drawn PE fiber.The unit cell remains orthorhombic even if the draw ratioreaches 50;as the draw ratio increases,the length in a and b axes are shortened while that in c ax-is changes quite insignificantly.When the draw ratio is over 10,two endothermic melting peakscan be seen in the DSC curves with corresponding peak temperature of 136.7-145.3℃.The lat-ter peak is attributed to the amount of extended chain crystal.
文摘A new concept of spinning-open-end jet-spinning, which combines the advantages of the false twist jet spinning and open end winning, was proposed, and a device was designed to practice this concept. The property of thc open-end jet spun yarn was measured and discussed in comparison with that of some other spun yarns.
文摘This paper described the physical behaviour of three types of denim cloths produced from rotor yarn, ring yarn and modified rotor yarn (prepared by adding conventional twist to rotor yarn) respectively. Experimental work showed that denim cloth produced from the modified rotor yarn has superior properties over conventional rotor yarn in terms of surface texture and appearance,tearing strength and resistance to abrasion.
文摘Consolidation of thermoplastic unidirectional(UD)lami-nate with friction spun core yarns was investigated,espe-cially the characterization of filament bundles in consoli-dation was analyzed.The results showed that the bundleeffect was affected considerably by processing conditions(applied pressure and processing time).The boundaryof the bundles was disappeared under suitable processingconditions and finally an even fiber/resin distributioncould be attained.In consolidation,filament bundlesgetting close each other and resin flowing into the bundl-es occurred simultaneously,and eventually the bundleswere fully impregnated by the resin.Fiber packing den-sity in UD-laminate was the same as that of frictionspun core yarn(55%-65% in volume)and was not af-fected significantly by processing conditions under thecurrent experimental conditions.
文摘The rotor spun yarn(OE yarn),twist of which is calledlayering twist,was added a few involving twist,and itsstructure and properties were measured.The experimen-tal results have shown that the morphological structure ofthe rotor spun yarn with modified twist was changed andits tensile properties and abrasion resistance were im-proved.
