The influence of γ-phase composition in WC-Co cemented carbides on its specific coercive force H_(sc) hasbeen studied by analysing the imitative alloys of γ-phase. The results show that the H_(sc) of γ-phase is low...The influence of γ-phase composition in WC-Co cemented carbides on its specific coercive force H_(sc) hasbeen studied by analysing the imitative alloys of γ-phase. The results show that the H_(sc) of γ-phase is lower thanthat of pure cobalt, because the solute W can raise γ-phase H_(sc) but the carbon exhibits more intense negativeeffect on H_(sc). The effect is enhanced with raising the C solubilities in γ-phase.展开更多
Ce_x(CoFe)_(3-x)O_4 ferrites with different contents of Ce have been prepared by wetchemical method. The phases, morphologies and magnetic properties of the products were studied.It has been found that the products we...Ce_x(CoFe)_(3-x)O_4 ferrites with different contents of Ce have been prepared by wetchemical method. The phases, morphologies and magnetic properties of the products were studied.It has been found that the products were a single phase with spinel structure and consisted of granular particles in most cases.The coercive force of the products increased with the increase of concentration of Ce￣(4+) in the reaction solution.On the other hand,if Ce￣(3+) and Ce(OH)_4 were present in the reaction solution,some rod-shape crystals in the products were observed, which causes a great increase in coercive force,and the optimum value was obtained when[Ce￣(3+)] was about 5% of the total([Ce￣(3+)]+[Ce￣(4+)]).展开更多
The experimental regularity and the mechanism of coercive force of metallic cobalt powders and WC Co mixture powders used for WC Co cemented carbides production were explored. The results show that the specific coer...The experimental regularity and the mechanism of coercive force of metallic cobalt powders and WC Co mixture powders used for WC Co cemented carbides production were explored. The results show that the specific coercive force H sc is a practical physical parameter which can show exactly the demagnetization characteristic of cobalt, and its magnitude is related to structure of cobalt. The H sc of WC Co mixture powders bears a simple positive going relation to Co content in them when the structure of cobalt is constant. It increases with fining and well distributing of cobalt particles in WC Co mixture powders due to the increase of the magnetic moment interaction of adjacent cobalt particles and the residual stress existing among powder particles by grinding.展开更多
Nd3＋ substituted spinel ferrites with formula MgxCd1-xNd0.03Fe1.97O4（x = 0.0.2,0.4,0.6.0.8 and 1.0）were prepared by oxalate co-precipitation method using novel microwave sintering technique. AR grade sulphates were...Nd3＋ substituted spinel ferrites with formula MgxCd1-xNd0.03Fe1.97O4（x = 0.0.2,0.4,0.6.0.8 and 1.0）were prepared by oxalate co-precipitation method using novel microwave sintering technique. AR grade sulphates were used as starting chemicals. The samples were sintered at optimized power of 70 W for10 min in a microwave oven（800 W）. The structural analysis of these samples was done by using X-ray diffraction, scanning electron microscope and Fourier transform IR techniques. The XRD analysis of the synthesized ferrite confirms the formation of cubic spinel structure of ferrite. The influence of Nd3＋substitution on various structural parameters of Mg-Cd ferrites was reported. IR study indicates the spectra contain two intense absorption bands around 600 and 400 cm^（-1） in addition with four extra bands. The magnetic properties of all ferrites were studied by using a vibration sample magnetometer.The crystallite and grain size dependant magnetic properties are observed. The composition Mg_（0.6）Cd_（0.4）Nd_（0.03）Fe_（1.97）O_4 has better magnetic properties that can be used in recording media. The fast synthesis of spinel ferrites is yielded due to use of the microwave sintering technique.展开更多
MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is ...MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is found that the Si/SiO2 substrate is more suitable for growing high-coercivity MnGa films than the glass substrate, which is the result of the isolated-island-like growth. A coercivity of 9.7 kOe can be achieved for the 10 nm MnGa films grown on Si/SiO2 substrate at substrate temperature TS of 450 °C.Optimized experimental conditions are specified by changing the thickness of the MnGa films and the temperature of the substrates.展开更多
Magnetic properties and crystallization behavior of nanocrystalline(Fe83.3Si4B8P4Cu0.7)100-xAlx(x=0-1.5 at%)alloys were investigated in this study.Experimental results show that coercive force decreases and saturation...Magnetic properties and crystallization behavior of nanocrystalline(Fe83.3Si4B8P4Cu0.7)100-xAlx(x=0-1.5 at%)alloys were investigated in this study.Experimental results show that coercive force decreases and saturation magnetization slightly decreases with the increase of Al content,but the glass forming ability has been improved at the same time.Crystallization behavior including the evolution of microstructure has also been studied.The growth ofα-Fe precipitated from the matrix is quick when it is annealed by conventional method and the mean size ofα-Fe grains increases from below 2-3 nm to 18-29 nm.Nanocrystalline(Fe83.3Si4B8P4Cu0.7)99Al1 alloy with coercive force of 8.9 A/m and saturation magnetization of 187 emu/g is probably a promising candidate in the field of soft magnetic materials.展开更多
文摘The influence of γ-phase composition in WC-Co cemented carbides on its specific coercive force H_(sc) hasbeen studied by analysing the imitative alloys of γ-phase. The results show that the H_(sc) of γ-phase is lower thanthat of pure cobalt, because the solute W can raise γ-phase H_(sc) but the carbon exhibits more intense negativeeffect on H_(sc). The effect is enhanced with raising the C solubilities in γ-phase.
文摘Ce_x(CoFe)_(3-x)O_4 ferrites with different contents of Ce have been prepared by wetchemical method. The phases, morphologies and magnetic properties of the products were studied.It has been found that the products were a single phase with spinel structure and consisted of granular particles in most cases.The coercive force of the products increased with the increase of concentration of Ce￣(4+) in the reaction solution.On the other hand,if Ce￣(3+) and Ce(OH)_4 were present in the reaction solution,some rod-shape crystals in the products were observed, which causes a great increase in coercive force,and the optimum value was obtained when[Ce￣(3+)] was about 5% of the total([Ce￣(3+)]+[Ce￣(4+)]).
文摘The experimental regularity and the mechanism of coercive force of metallic cobalt powders and WC Co mixture powders used for WC Co cemented carbides production were explored. The results show that the specific coercive force H sc is a practical physical parameter which can show exactly the demagnetization characteristic of cobalt, and its magnitude is related to structure of cobalt. The H sc of WC Co mixture powders bears a simple positive going relation to Co content in them when the structure of cobalt is constant. It increases with fining and well distributing of cobalt particles in WC Co mixture powders due to the increase of the magnetic moment interaction of adjacent cobalt particles and the residual stress existing among powder particles by grinding.
文摘Nd3＋ substituted spinel ferrites with formula MgxCd1-xNd0.03Fe1.97O4（x = 0.0.2,0.4,0.6.0.8 and 1.0）were prepared by oxalate co-precipitation method using novel microwave sintering technique. AR grade sulphates were used as starting chemicals. The samples were sintered at optimized power of 70 W for10 min in a microwave oven（800 W）. The structural analysis of these samples was done by using X-ray diffraction, scanning electron microscope and Fourier transform IR techniques. The XRD analysis of the synthesized ferrite confirms the formation of cubic spinel structure of ferrite. The influence of Nd3＋substitution on various structural parameters of Mg-Cd ferrites was reported. IR study indicates the spectra contain two intense absorption bands around 600 and 400 cm^（-1） in addition with four extra bands. The magnetic properties of all ferrites were studied by using a vibration sample magnetometer.The crystallite and grain size dependant magnetic properties are observed. The composition Mg_（0.6）Cd_（0.4）Nd_（0.03）Fe_（1.97）O_4 has better magnetic properties that can be used in recording media. The fast synthesis of spinel ferrites is yielded due to use of the microwave sintering technique.
基金financially supported by the National Natural Science Foundation of China (Nos. 51590883, 51471167, 51271179 and 51571194)the project of Chinese Academy of Sciences with grant number KJZD-EW-M05-3supported by a Joint Research Project from Ministry of Science, ICT and Future Planning/Korea Research Council for Industrial Science and Technology
文摘MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is found that the Si/SiO2 substrate is more suitable for growing high-coercivity MnGa films than the glass substrate, which is the result of the isolated-island-like growth. A coercivity of 9.7 kOe can be achieved for the 10 nm MnGa films grown on Si/SiO2 substrate at substrate temperature TS of 450 °C.Optimized experimental conditions are specified by changing the thickness of the MnGa films and the temperature of the substrates.
基金supported by Magnetic Materials and Advanced Devices Departments,Ningbo Institute of Material Technology and Engineering,Chinese Academy of Sciences
文摘Magnetic properties and crystallization behavior of nanocrystalline(Fe83.3Si4B8P4Cu0.7)100-xAlx(x=0-1.5 at%)alloys were investigated in this study.Experimental results show that coercive force decreases and saturation magnetization slightly decreases with the increase of Al content,but the glass forming ability has been improved at the same time.Crystallization behavior including the evolution of microstructure has also been studied.The growth ofα-Fe precipitated from the matrix is quick when it is annealed by conventional method and the mean size ofα-Fe grains increases from below 2-3 nm to 18-29 nm.Nanocrystalline(Fe83.3Si4B8P4Cu0.7)99Al1 alloy with coercive force of 8.9 A/m and saturation magnetization of 187 emu/g is probably a promising candidate in the field of soft magnetic materials.
