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
The Plasma-Enhanced Chemical Vapor Deposition (PECVD) method is widely used compared to other methods to deposit hydrogenated silicon Si:H. In this work, a systematic variation of deposition parameters was done to stu...The Plasma-Enhanced Chemical Vapor Deposition (PECVD) method is widely used compared to other methods to deposit hydrogenated silicon Si:H. In this work, a systematic variation of deposition parameters was done to study the sensitivities and the effects of these parameters on the intrinsic layer material properties. Samples were deposited with 13.56 MHZ PECVD through decomposition of silane diluted with argon. Undoped samples depositions were made in this experiment in order to obtain the transition from the amorphous to nanocrystalline phase materials. The substrate temperature was fixed at 200oC. The influence of depositions parameters on the optical proprieties of the thin films was studied by UV-Vis-NIR spectroscopy. The structural evolution was also studied by Raman spectroscopy and X-ray diffraction (XRD). The structural evolution studies show that beyond 200 W radio frequency power value, we observed an amorphous-nanocrystalline transition, with an increase in crystalline fraction by increasing RF power and working pressure. The deposition rates are found in the range 6 - 10 /s. A correlation between structural and optical properties has been found and discussed.展开更多
(Cu43Zr48Al9)98Y2 amorphous alloy bar was prepared by the arc melting copper mold absorption casting method,and then,the amorphous alloy was annealed at different temperatures for different times.The influence of heat...(Cu43Zr48Al9)98Y2 amorphous alloy bar was prepared by the arc melting copper mold absorption casting method,and then,the amorphous alloy was annealed at different temperatures for different times.The influence of heating rate on thermal expansion and thermal stability was studied by thermomechanical analysis(TMA),and the microstructure evolution of the amorphous alloy during structural relaxation and crystallization was studied by XRD and TEM.Results show that the structural evolution behavior of the(Cu43Zr48Al9)98Y2 amorphous alloy can be divided into five different stages(structural relaxation preparation stage,structural relaxation stage,first crystallization stage,second crystallization stage,and grain growth stage).When the heating rate is 20 K/min,the amorphous alloy has the smallest thermal expansion coefficient and the best thermal stability.The width of the supercooled liquid region is 66.42 K.Samples with different relaxation states were prepared by annealing at the heating rate of 20 K/min.The structural evolution of amorphous alloys with different relaxation states is as follows:amorphous→CuZr2+AlCu2Zr7→CuZr2+AlCu2Zr7+CuZr(B2)+CuZr(M)+Cu10Zr7→CuZr2+AlCu2Zr7+CuZr(B2)+CuZr(M).After annealing at 706 K and 726 K(in the supercooled liquid region)for 1.5 h,the amorphous-nanocrystalline composites were obtained.When the annealing temperature is 706 K,the crystallization process of the sample is as follows:amorphous→Cu10Zr7→Cu10Zr7+CuZr,and for the sample at 726 K,it is as follows:amorphous→CuZr2+AlCu2Zr7+Cu10Zr7→Cu10Zr7+CuZr2→CuZr2+CuZr(B2)+Cu10Zr7.展开更多
The Gd_(60)Co_(30)Fe_(10)alloy ribbons with different solidification cooling rates were prepared by modifying the melt-spinning speed of 6.0,12.5,25.0 and 50.0 m·s^(-1)·With cooling rate decreasing,the(Fe,Co...The Gd_(60)Co_(30)Fe_(10)alloy ribbons with different solidification cooling rates were prepared by modifying the melt-spinning speed of 6.0,12.5,25.0 and 50.0 m·s^(-1)·With cooling rate decreasing,the(Fe,Co)5 Gd and hcp-Gd nanocrystalline was in situ precipitated among the amorphous matrix,which resulted in the composition change of the amorphous phase.Because of the only slight amount of crystalline phase in Gd_(60)Co_(30)Fe_(10)alloys,the magnetic and magnetocaloric properties mainly depend on the amorphous phase,and all the magnetic entropy change versus temperature(|Δ|SMI-T)curves are table-like,indicating the suitability for Ericsson cycle.The magnetic transition temperature of the Gd_(60)Co_(30)Fe_(10)alloy at a melt-spinning speed of 6.0 m·s^(-1) shifted obviously to the lower value with the applied magnetic fields increasing.The peak value of magnetic entropy change(|ΔSMpk|)is 2.19 J·kg^(-1)·K^(-1)at217 K under the magnetic field change of 0-2 T,and the table-like region is 200-230 K.It was proved that the moderate reduction of the cooling rate will not deteriorate the magnetocaloric performance of the Gd_(60)Co_(30)Fe_(10)ribbons seriously.展开更多
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The Plasma-Enhanced Chemical Vapor Deposition (PECVD) method is widely used compared to other methods to deposit hydrogenated silicon Si:H. In this work, a systematic variation of deposition parameters was done to study the sensitivities and the effects of these parameters on the intrinsic layer material properties. Samples were deposited with 13.56 MHZ PECVD through decomposition of silane diluted with argon. Undoped samples depositions were made in this experiment in order to obtain the transition from the amorphous to nanocrystalline phase materials. The substrate temperature was fixed at 200oC. The influence of depositions parameters on the optical proprieties of the thin films was studied by UV-Vis-NIR spectroscopy. The structural evolution was also studied by Raman spectroscopy and X-ray diffraction (XRD). The structural evolution studies show that beyond 200 W radio frequency power value, we observed an amorphous-nanocrystalline transition, with an increase in crystalline fraction by increasing RF power and working pressure. The deposition rates are found in the range 6 - 10 /s. A correlation between structural and optical properties has been found and discussed.
基金financially supported by the Principal Fund of Xi’an Technological University,China(Grant No.0852-302021407)
文摘(Cu43Zr48Al9)98Y2 amorphous alloy bar was prepared by the arc melting copper mold absorption casting method,and then,the amorphous alloy was annealed at different temperatures for different times.The influence of heating rate on thermal expansion and thermal stability was studied by thermomechanical analysis(TMA),and the microstructure evolution of the amorphous alloy during structural relaxation and crystallization was studied by XRD and TEM.Results show that the structural evolution behavior of the(Cu43Zr48Al9)98Y2 amorphous alloy can be divided into five different stages(structural relaxation preparation stage,structural relaxation stage,first crystallization stage,second crystallization stage,and grain growth stage).When the heating rate is 20 K/min,the amorphous alloy has the smallest thermal expansion coefficient and the best thermal stability.The width of the supercooled liquid region is 66.42 K.Samples with different relaxation states were prepared by annealing at the heating rate of 20 K/min.The structural evolution of amorphous alloys with different relaxation states is as follows:amorphous→CuZr2+AlCu2Zr7→CuZr2+AlCu2Zr7+CuZr(B2)+CuZr(M)+Cu10Zr7→CuZr2+AlCu2Zr7+CuZr(B2)+CuZr(M).After annealing at 706 K and 726 K(in the supercooled liquid region)for 1.5 h,the amorphous-nanocrystalline composites were obtained.When the annealing temperature is 706 K,the crystallization process of the sample is as follows:amorphous→Cu10Zr7→Cu10Zr7+CuZr,and for the sample at 726 K,it is as follows:amorphous→CuZr2+AlCu2Zr7+Cu10Zr7→Cu10Zr7+CuZr2→CuZr2+CuZr(B2)+Cu10Zr7.
基金financially supported by Guangdong Major Project of Basic and Applied Basic Research,China (Grant No.2019B030302010)the National Natural Science Foundation of China (No.52301212,52071157,52071222)+1 种基金the National Key Research and Development Program of China (Grant No.2021YFA0716302)the open research fund of Songshan Lake Materials Laboratory (No.2022SLABFN11)。
基金financially supported by the National Natural Science Foundation of China(No.51701003)the Natural Science Foundation of Anhui Province(No.1908085ME147)the International Cooperation and Exchanges in Anhui Provincial Key Project of Research(No.202004b11020010)。
文摘The Gd_(60)Co_(30)Fe_(10)alloy ribbons with different solidification cooling rates were prepared by modifying the melt-spinning speed of 6.0,12.5,25.0 and 50.0 m·s^(-1)·With cooling rate decreasing,the(Fe,Co)5 Gd and hcp-Gd nanocrystalline was in situ precipitated among the amorphous matrix,which resulted in the composition change of the amorphous phase.Because of the only slight amount of crystalline phase in Gd_(60)Co_(30)Fe_(10)alloys,the magnetic and magnetocaloric properties mainly depend on the amorphous phase,and all the magnetic entropy change versus temperature(|Δ|SMI-T)curves are table-like,indicating the suitability for Ericsson cycle.The magnetic transition temperature of the Gd_(60)Co_(30)Fe_(10)alloy at a melt-spinning speed of 6.0 m·s^(-1) shifted obviously to the lower value with the applied magnetic fields increasing.The peak value of magnetic entropy change(|ΔSMpk|)is 2.19 J·kg^(-1)·K^(-1)at217 K under the magnetic field change of 0-2 T,and the table-like region is 200-230 K.It was proved that the moderate reduction of the cooling rate will not deteriorate the magnetocaloric performance of the Gd_(60)Co_(30)Fe_(10)ribbons seriously.
