The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and ...The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and specific magnetization of the FeCo alloy particles depend on the Co content.展开更多
The facile hydrothennal method was used to synthesize Fe3O4 nanoparticles with an average diameter of 1 1nm. The pure body-centered cubic （bcc）-Fe nanoparticles were prepared by reduction of Fe3O4 nanoparticles powd...The facile hydrothennal method was used to synthesize Fe3O4 nanoparticles with an average diameter of 1 1nm. The pure body-centered cubic （bcc）-Fe nanoparticles were prepared by reduction of Fe3O4 nanoparticles powder in H2 atmosphere. The structure, morphology and magnetic＇properties of the products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, thermogravimetric analysis-differential scanning calorimetry （TGA-DSC） and vibrating sample magnetometer （VSM）. The results showed that the as-prepared Fe3O4 nanoparticles had a relatively homogeneous size. The particle diameters became bigger with the increase of reaction time. The growth kinetics of the Fe3O4 nanoparticles was also briefly discussed. The products exhibited superparamagnetic properties at room temperature and the specific saturation magnetization was dependent on the particle sizes.展开更多
Tianjin Institute of Hard Alloy,Tianjin 300222,China ABSTRACT The effects of solutes of wolfram and carbon on specific saturation magnetization(4πσ)of cobalt have been examined on the basis of the measurement of Ana...Tianjin Institute of Hard Alloy,Tianjin 300222,China ABSTRACT The effects of solutes of wolfram and carbon on specific saturation magnetization(4πσ)of cobalt have been examined on the basis of the measurement of Ana for hexagonal typeα-Co and cubic typeβ-Co.The Co-W-C solid solution simulative alloys have been fabricated according to binder composition in WC-Co cemented carbides and the effect of its component and structure on its Ana has been discussed too.It is pointed out that the Co phase structural factor must be considered as measuring the Ana of WC-Co cemented carbides.展开更多
FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at ...FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at 573 K for 90 rain. The ordering degree of the powders lattice structure was analyzed by X-ray diffraction （XRD）. The measurement of specific saturation magnetization was carried out by vibrating samples magnetometer （VSM）. Complex permittivity and complex permeability in the frequency band of 0.5-18 GHz were measured with the vector network analyzer. The ordering degree of the superlattice structure increased from 0.2＇7 to 0.49. Complex permittivity and complex permeability decreased with increasing Si content. After ordering, the specific saturation magnetization decreased from 134.2 to 85.0 A.m2.kg-1. For use in anti-EMI material, the total contents of Si and Al in FeSiAl alloys should be controlled at a low level.展开更多
Fe68Zr20B12 amorphous alloy was prepared by mechanical alloying（MA） method and annealed at different temperatures. Microstructures and magnetic properties of Fe68Zr20B12 alloys as-milled and annealed at 693, 843, 94...Fe68Zr20B12 amorphous alloy was prepared by mechanical alloying（MA） method and annealed at different temperatures. Microstructures and magnetic properties of Fe68Zr20B12 alloys as-milled and annealed at 693, 843, 943 and 993 K were studied. The raw powders（Fe, Zr, B） formed b. c. c. α-Fe solid solution at early stages of MA and then transformed into amorphous alloy. Grain size（D） of Fe68Zr20B12 alloys increases with increasing annealing temperature and keeps at nanometer level. The specific saturation magnetization（σs） increases with increasing annealing temperature from 300 K to 943 K, and then decreases with annealing temperature at 993 K because of the precipitation of Fe3B.展开更多
Metal Fe/Pd compositionally modulated films(CMFs) were prepared by vapour depo- sition from two sources onto glass substrate under vacuum.The modulation and crystal structures of the films were examined by X-ray diffr...Metal Fe/Pd compositionally modulated films(CMFs) were prepared by vapour depo- sition from two sources onto glass substrate under vacuum.The modulation and crystal structures of the films were examined by X-ray diffraction.The magnetic properties were determined by vibrating sample magnetometer.The Pd layers in the Fe/Pd CMFs are of fcc structure,and the Fe layer structure transits from bcc into amorphous,state with decreasing thickness of Fe layer.The dependence of specific saturation magnetization on thickness of Fe layers has also been discussed.展开更多
The stress state and floating sinking reqularity of various particles in fly ash in water were analyzed. The formula for calculating the floating sinking rate was given. And the formula for calculating the magnetic fo...The stress state and floating sinking reqularity of various particles in fly ash in water were analyzed. The formula for calculating the floating sinking rate was given. And the formula for calculating the magnetic force needed to separate magnetic beads from magnetic separator was also obtained.展开更多
On the basis of study on physical and chemical properties of magnetic bead (MB) in fly ash (FA), the paper gives out the separation methods of MB and results of three separating process. The result of comparative test...On the basis of study on physical and chemical properties of magnetic bead (MB) in fly ash (FA), the paper gives out the separation methods of MB and results of three separating process. The result of comparative test in size, density, stability, magnetic material content, specific magnetic susceptibility (SMS), medium recovery oxidation resistance and wear resistance between MB and magnetic fines currently used in dense medium separation leads to that using MB recovered from fly ash is used as medium solids in coal cleaning in stead of magnetic fines not only have no influence upon taryests of separation, but can bring good economic and social benefits.展开更多
Soft magnetic metallic materials have been widely used for absorbing electromagnetic wave.Flaky Fe 86 t Si t Al 14（t=9,11,14 and 16） alloys powders were prepared from melt-quenched ribbons by annealing and milling.I...Soft magnetic metallic materials have been widely used for absorbing electromagnetic wave.Flaky Fe 86 t Si t Al 14（t=9,11,14 and 16） alloys powders were prepared from melt-quenched ribbons by annealing and milling.In a previous report we discussed the order-disordered structure of this alloys.In this article,we studied their electron structure.Covalence electron numbers of（111） and（100） plane increase with increasing Si content but Bohr magneton decreases.Complex permittivity and complex permeability are both decreased with increasing Si content t.The lowest value of reflectivity among the four alloys is originated from Fe 70 Si 14 Al 14.The peak values of reflectivity are all lower than 10 dB,and the absorbing frequency range（R 10 dB） increases from 1 to 2 GHz when t reaches 16.展开更多
文摘The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and specific magnetization of the FeCo alloy particles depend on the Co content.
基金the National Natural Science Foundation of China （No.90206017） National High Technical Reasearch and Development Programme of China （No.2003BA301A21 ）.
文摘The facile hydrothennal method was used to synthesize Fe3O4 nanoparticles with an average diameter of 1 1nm. The pure body-centered cubic （bcc）-Fe nanoparticles were prepared by reduction of Fe3O4 nanoparticles powder in H2 atmosphere. The structure, morphology and magnetic＇properties of the products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, thermogravimetric analysis-differential scanning calorimetry （TGA-DSC） and vibrating sample magnetometer （VSM）. The results showed that the as-prepared Fe3O4 nanoparticles had a relatively homogeneous size. The particle diameters became bigger with the increase of reaction time. The growth kinetics of the Fe3O4 nanoparticles was also briefly discussed. The products exhibited superparamagnetic properties at room temperature and the specific saturation magnetization was dependent on the particle sizes.
文摘Tianjin Institute of Hard Alloy,Tianjin 300222,China ABSTRACT The effects of solutes of wolfram and carbon on specific saturation magnetization(4πσ)of cobalt have been examined on the basis of the measurement of Ana for hexagonal typeα-Co and cubic typeβ-Co.The Co-W-C solid solution simulative alloys have been fabricated according to binder composition in WC-Co cemented carbides and the effect of its component and structure on its Ana has been discussed too.It is pointed out that the Co phase structural factor must be considered as measuring the Ana of WC-Co cemented carbides.
文摘FeSiAl alloys ribbons synthesized by melt-quench were annealed in vacuum at 873 K for 60 rain. The flaky powders were prepared by milling the annealed ribbons for 70 h. After milling, the powders were heat treated at 573 K for 90 rain. The ordering degree of the powders lattice structure was analyzed by X-ray diffraction （XRD）. The measurement of specific saturation magnetization was carried out by vibrating samples magnetometer （VSM）. Complex permittivity and complex permeability in the frequency band of 0.5-18 GHz were measured with the vector network analyzer. The ordering degree of the superlattice structure increased from 0.2＇7 to 0.49. Complex permittivity and complex permeability decreased with increasing Si content. After ordering, the specific saturation magnetization decreased from 134.2 to 85.0 A.m2.kg-1. For use in anti-EMI material, the total contents of Si and Al in FeSiAl alloys should be controlled at a low level.
基金Funded by the Science and Technology Development Project of Jilin Province (No. 20040506-3)
文摘Fe68Zr20B12 amorphous alloy was prepared by mechanical alloying（MA） method and annealed at different temperatures. Microstructures and magnetic properties of Fe68Zr20B12 alloys as-milled and annealed at 693, 843, 943 and 993 K were studied. The raw powders（Fe, Zr, B） formed b. c. c. α-Fe solid solution at early stages of MA and then transformed into amorphous alloy. Grain size（D） of Fe68Zr20B12 alloys increases with increasing annealing temperature and keeps at nanometer level. The specific saturation magnetization（σs） increases with increasing annealing temperature from 300 K to 943 K, and then decreases with annealing temperature at 993 K because of the precipitation of Fe3B.
文摘Metal Fe/Pd compositionally modulated films(CMFs) were prepared by vapour depo- sition from two sources onto glass substrate under vacuum.The modulation and crystal structures of the films were examined by X-ray diffraction.The magnetic properties were determined by vibrating sample magnetometer.The Pd layers in the Fe/Pd CMFs are of fcc structure,and the Fe layer structure transits from bcc into amorphous,state with decreasing thickness of Fe layer.The dependence of specific saturation magnetization on thickness of Fe layers has also been discussed.
文摘The stress state and floating sinking reqularity of various particles in fly ash in water were analyzed. The formula for calculating the floating sinking rate was given. And the formula for calculating the magnetic force needed to separate magnetic beads from magnetic separator was also obtained.
文摘On the basis of study on physical and chemical properties of magnetic bead (MB) in fly ash (FA), the paper gives out the separation methods of MB and results of three separating process. The result of comparative test in size, density, stability, magnetic material content, specific magnetic susceptibility (SMS), medium recovery oxidation resistance and wear resistance between MB and magnetic fines currently used in dense medium separation leads to that using MB recovered from fly ash is used as medium solids in coal cleaning in stead of magnetic fines not only have no influence upon taryests of separation, but can bring good economic and social benefits.
基金State Key Laboratory of Electronic Thin Films and Integrated Devices for support of this work (KFJJ200815)supported by the Scientific Research Fund of Sichuan Provincial Education Department,China (08ZA026)Talents Project of Xihua University,China (R1020106)
文摘Soft magnetic metallic materials have been widely used for absorbing electromagnetic wave.Flaky Fe 86 t Si t Al 14（t=9,11,14 and 16） alloys powders were prepared from melt-quenched ribbons by annealing and milling.In a previous report we discussed the order-disordered structure of this alloys.In this article,we studied their electron structure.Covalence electron numbers of（111） and（100） plane increase with increasing Si content but Bohr magneton decreases.Complex permittivity and complex permeability are both decreased with increasing Si content t.The lowest value of reflectivity among the four alloys is originated from Fe 70 Si 14 Al 14.The peak values of reflectivity are all lower than 10 dB,and the absorbing frequency range（R 10 dB） increases from 1 to 2 GHz when t reaches 16.
