MoN was prepared by rare earth Gd thermaldiffused permeation method via solid–gas interface reaction using（NH_4）_4[NiMo6O_24H_6]·7H_2O（abbreviated as NiMo6） as the precursor. Thermo-gravimetric differential ...MoN was prepared by rare earth Gd thermaldiffused permeation method via solid–gas interface reaction using（NH_4）_4[NiMo6O_24H_6]·7H_2O（abbreviated as NiMo6） as the precursor. Thermo-gravimetric differential thermal analysis（TG–DTA） was used to study the product＇s stability. The results of X-ray diffractometer（XRD）and X-ray photoelectron spectroscopy（XPS） indicate that a new hexagonal crystal MoN forms after the rare earth gas permeation and Gd3＋are diffused as substitution ions into the crystal lattice of MoN, and the surface valence of elemental content was measured by XPS. The conductivity results by direct current（DC） four-probe method show that MoN obtained from the Gd thermal permeation exhibits conductor character in the temperature range of 298–740 K and semiconductor behavior in 740–800 K.展开更多
Three alkaline earth silicate phosphors: Sr2MgSi2O7∶Eu, Dy, Gd, Sr3MgSi2O8∶Eu, Dy, Gd and Sr2MgSi2O7∶Eu, Dy were prepared and their luminescent properties were investigated. The Photoluminescence (PL) measurements ...Three alkaline earth silicate phosphors: Sr2MgSi2O7∶Eu, Dy, Gd, Sr3MgSi2O8∶Eu, Dy, Gd and Sr2MgSi2O7∶Eu, Dy were prepared and their luminescent properties were investigated. The Photoluminescence (PL) measurements indicated that the phosphors gave a longer emitting phosphorescence phenomenon by comparing with those without Gd2O3 activator, in which a better afterglow characteristic was observed by adding Gd2O3 to the phosphors. While little influence on the structure of luminescent materials was observed via XRD spectra, and obvious emission wavelength shift was exhibited due to the differences in the structure parameters of the two hosts. The results revealed that the improvement was due to nonequivalent substitution to produce more e-traps, and energy transfer from Gd3+ to Dy3+, to boost the performance of Sr2MgSi2O7∶Eu, Dy phosphor. Role of Gd3+ co-doped into Sr2MgSi2O7∶Eu, Dy matrix and the possible long-lasting phosphorescence progress were discussed.展开更多
The microstructure observation,tensile test,electrochemical measurement,and corrosion morphology characterization were conducted to study the effect of Gd on the microstructure,mechanical properties,and corrosion beha...The microstructure observation,tensile test,electrochemical measurement,and corrosion morphology characterization were conducted to study the effect of Gd on the microstructure,mechanical properties,and corrosion behavior of as-homogenized Mg−8Li−3Al−2Zn−0.2Zr(LAZ832−0.2Zr)alloy.The addition of trace Gd can improve the mechanical properties of as-homogenized LAZ832−0.2Zr alloy by refining the microstructure,reducing the content of AlLi softening phase,and forming Al_(2)Gd strengthening phase.Meanwhile,the addition of trace Gd can weaken the microgalvanic corrosion between matrix phase and AlLi phase,inhibit the galvanic corrosion betweenα-Mg phase andβ-Li phase,and result in the formation of dense oxide film containing Gd_(2)O_(3),thereby improving the corrosion resistance of the alloy.When the Gd content is 1.0 wt.%,the alloy shows the best comprehensive properties with the ultimate tensile strength of 189.8 MPa,elongation of 42.3%,and corrosion rate(determined by hydrogen evolution)of 0.86 mm·a^(−1).展开更多
Al-5Ti-B and Al-5Ti-B-Gd master alloy refiners were fabricated by fluorine salt casting method.The microstructure and phase constitution of the master alloys were investigated by scanning electron microscopy (SEM),tra...Al-5Ti-B and Al-5Ti-B-Gd master alloy refiners were fabricated by fluorine salt casting method.The microstructure and phase constitution of the master alloys were investigated by scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray diffraction (XRD).The results show that Al-Ti-B alloy refiner consists of Al_(3)Ti phase and TiB2 phase.After Gd is introduced into the intermediate alloy,Ti_(2)Al_(20)Gd phase appears in the alloy,the size of Al_(3)Ti is significantly reduced,and Ti-Al-Gd phase is found in the edge of Al_(3)Ti phase.At the same time,some independent Ti-Al-Gd phases appear in local areas,which are Ti_(2)Al_(20)Gd phase determined by micro-area electron diffraction analysis.Analysis and calculation results of the high-resolution images of the Ti_(2)Al_(20)Gd/Al structure show that there is no other compound at the junction between the Ti_(2)Al_(20)Gd phase and Al,and Ti_(2)Al_(20)Gd phase has a great difference in atomic space with the α-Al,which cannot be directly used as heterogeneous nucleus.But,after being decomposed in the aluminum melt,the Ti_(2)Al_(20)Gd phase can promote the refinement effect of the refiner.In the Al-Ti-B-Gd master alloy,there are many dispersed Al_(3)Ti particles with a size of less than 1 μm,which can promote the Al-5Ti-B refining effect.展开更多
基金financially supported by National Natural Science Foundation of China (No. 51272163, No. 51274143)
文摘MoN was prepared by rare earth Gd thermaldiffused permeation method via solid–gas interface reaction using（NH_4）_4[NiMo6O_24H_6]·7H_2O（abbreviated as NiMo6） as the precursor. Thermo-gravimetric differential thermal analysis（TG–DTA） was used to study the product＇s stability. The results of X-ray diffractometer（XRD）and X-ray photoelectron spectroscopy（XPS） indicate that a new hexagonal crystal MoN forms after the rare earth gas permeation and Gd3＋are diffused as substitution ions into the crystal lattice of MoN, and the surface valence of elemental content was measured by XPS. The conductivity results by direct current（DC） four-probe method show that MoN obtained from the Gd thermal permeation exhibits conductor character in the temperature range of 298–740 K and semiconductor behavior in 740–800 K.
基金the National Natural Science Foundation (20376009)the Liaoning Natural Science Foundation(20032129) of China
文摘Three alkaline earth silicate phosphors: Sr2MgSi2O7∶Eu, Dy, Gd, Sr3MgSi2O8∶Eu, Dy, Gd and Sr2MgSi2O7∶Eu, Dy were prepared and their luminescent properties were investigated. The Photoluminescence (PL) measurements indicated that the phosphors gave a longer emitting phosphorescence phenomenon by comparing with those without Gd2O3 activator, in which a better afterglow characteristic was observed by adding Gd2O3 to the phosphors. While little influence on the structure of luminescent materials was observed via XRD spectra, and obvious emission wavelength shift was exhibited due to the differences in the structure parameters of the two hosts. The results revealed that the improvement was due to nonequivalent substitution to produce more e-traps, and energy transfer from Gd3+ to Dy3+, to boost the performance of Sr2MgSi2O7∶Eu, Dy phosphor. Role of Gd3+ co-doped into Sr2MgSi2O7∶Eu, Dy matrix and the possible long-lasting phosphorescence progress were discussed.
基金financial supports from the Anhui Provincial Natural Science Foundation,China (No.2208085QE124)the Natural Science Foundation of the Education Department of Anhui Province,China (No.KJ2021A0394)the Open Project of Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials,China (No.GFST2021KF04)。
文摘The microstructure observation,tensile test,electrochemical measurement,and corrosion morphology characterization were conducted to study the effect of Gd on the microstructure,mechanical properties,and corrosion behavior of as-homogenized Mg−8Li−3Al−2Zn−0.2Zr(LAZ832−0.2Zr)alloy.The addition of trace Gd can improve the mechanical properties of as-homogenized LAZ832−0.2Zr alloy by refining the microstructure,reducing the content of AlLi softening phase,and forming Al_(2)Gd strengthening phase.Meanwhile,the addition of trace Gd can weaken the microgalvanic corrosion between matrix phase and AlLi phase,inhibit the galvanic corrosion betweenα-Mg phase andβ-Li phase,and result in the formation of dense oxide film containing Gd_(2)O_(3),thereby improving the corrosion resistance of the alloy.When the Gd content is 1.0 wt.%,the alloy shows the best comprehensive properties with the ultimate tensile strength of 189.8 MPa,elongation of 42.3%,and corrosion rate(determined by hydrogen evolution)of 0.86 mm·a^(−1).
文摘Al-5Ti-B and Al-5Ti-B-Gd master alloy refiners were fabricated by fluorine salt casting method.The microstructure and phase constitution of the master alloys were investigated by scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray diffraction (XRD).The results show that Al-Ti-B alloy refiner consists of Al_(3)Ti phase and TiB2 phase.After Gd is introduced into the intermediate alloy,Ti_(2)Al_(20)Gd phase appears in the alloy,the size of Al_(3)Ti is significantly reduced,and Ti-Al-Gd phase is found in the edge of Al_(3)Ti phase.At the same time,some independent Ti-Al-Gd phases appear in local areas,which are Ti_(2)Al_(20)Gd phase determined by micro-area electron diffraction analysis.Analysis and calculation results of the high-resolution images of the Ti_(2)Al_(20)Gd/Al structure show that there is no other compound at the junction between the Ti_(2)Al_(20)Gd phase and Al,and Ti_(2)Al_(20)Gd phase has a great difference in atomic space with the α-Al,which cannot be directly used as heterogeneous nucleus.But,after being decomposed in the aluminum melt,the Ti_(2)Al_(20)Gd phase can promote the refinement effect of the refiner.In the Al-Ti-B-Gd master alloy,there are many dispersed Al_(3)Ti particles with a size of less than 1 μm,which can promote the Al-5Ti-B refining effect.
