Aluminum oxide inclusions in SWRS82B steel seriously affect the drawing performance of steel strands.The effects of different addition amounts of yttrium(within the range of 0%–0.026%)on the composition,morphology,si...Aluminum oxide inclusions in SWRS82B steel seriously affect the drawing performance of steel strands.The effects of different addition amounts of yttrium(within the range of 0%–0.026%)on the composition,morphology,size and spacing of aluminum oxide inclusions were studied by scanning electron microscopy and energy spectrum analysis.Based on classical thermodynamics and FactSage software,the predominance diagram of inclusions in Fe–O–S–Y system and the effect of the addition of rare earth yttrium on the stability of alumina inclusions were calculated.The results showed that molten steel was modified by adding the rare earth element yttrium.It can be inferred that the approximate route of target inclusion modification was:Al_(2)O_(3)→Y_(2)S_(3)+YAlO_(3)+Al_(2)O_(3)→Y_(2)S_(3)+YAlO_(3)+Y_(2)O_(2)S+YAlO_(3)+Al_(2)O_(3)→Y_(2)S_(3)+Y_(2)O_(2)S.The experimental samples with 0.026%added yttrium had the best inclusion characteristics,in which the inclusion surface density distribution was uniform,and the interfacial distance between inclusions was mainly in the range of 100–500μm.After modification,the average inclusion size in molten steel was reduced by 6.9–8.6μm.The mechanism of yttrium modification was discussed based on actual calculation results and experimental results.展开更多
Polystyrene doped with yttrium ethoxide was prepared. The coordination between yttrium atom and benzene ring in the polystyrene doped with yttrium ethoxide was confirmed by means of IR, XPS.
The refinement and modification of Al-Cu alloys can result in the change of solidification process,e.g.the nucleation temperature,eutectic arrest,solidification range and cooling rate.Specially,the refinement and modi...The refinement and modification of Al-Cu alloys can result in the change of solidification process,e.g.the nucleation temperature,eutectic arrest,solidification range and cooling rate.Specially,the refinement and modification of Al-Cu alloy can be achieved by addition of rare earth.In this paper,the effect of yttrium on the microstructure and solidification process of Al-Cu alloys was investigated by the method of thermal analysis.Meanwhile,the microstructure of Al-Cu alloy was observed by OM and SEM.The results show that θ(Al2Cu) phases change from mesh structure into fish-bone shape.Analysis indicates that yttrium causes a depression of solid-liquid coexistence zone and the disappearance of recalescence of the eutectic arrest.展开更多
Y-Modified USY was prepared by ion exchange of USY slurry with 0.01 mol·L-1 Y(NO3)3. Phosphotungstic acid (HPW) catalyst supported on USY and Y-USY was prepared by an impregnation method. The materials were chara...Y-Modified USY was prepared by ion exchange of USY slurry with 0.01 mol·L-1 Y(NO3)3. Phosphotungstic acid (HPW) catalyst supported on USY and Y-USY was prepared by an impregnation method. The materials were characterized by NH3-TPD, XRD, and N2 adsorption. The activity for the removal of thiophene was examined in a three-necked flask. The sulfur content of model compound was tested on WK-2D microcoulometric detector. The effect of yttrium and HPW content, reaction temperature and catalysts, activation temperature on the activity of catalysts were investigated. It was shown that the oxidation activity of thiophene decreased with the increase of Y content except for the catalyst of Y 5%. HPW content had limit influence on activity of catalysts. The optimal reaction temperature and activation temperature were 40 and 320 ℃, respectively.展开更多
The modification of corrosion resistance in aqueous solution on 304L austenitic stainless steel by yttrium implantation was studied by electrochemical measurement and surface analysis.The results showed that corrosion...The modification of corrosion resistance in aqueous solution on 304L austenitic stainless steel by yttrium implantation was studied by electrochemical measurement and surface analysis.The results showed that corrosion resistance of yttrium-implanted samples had been significantly improved. After implantation the free corrosion current and passive current density in sulphuric acid solution were reduced to 1/4～ 1/6 of that of blank samples, and the breakdown potential in chloride contained solution was raised by 30～50 mV. By AES analysis it was found that yttrium was homogeneously distributed in implanted layer as over-saturated solid solution. The ratio of chromium to iron content and the thickness of oxygen-contained layer increased in implanted layer. It was clearly that surface alloying, which modified the surface composition of steel, played an important part in the improvement of corrosion resistance, resulted from the improvement on the property of passivity film of implanted samples.展开更多
Recently, more and more interest has been focused on zirconia for its unique characteristics. In this paper, via the preceding preparation technique, yttrium can be successfully incorporated into nano-zirconia by a ca...Recently, more and more interest has been focused on zirconia for its unique characteristics. In this paper, via the preceding preparation technique, yttrium can be successfully incorporated into nano-zirconia by a cationic surfactant-assisted route. The methods of XRD, TEM, EDS, Uv-vis and N2 adsorption-desorption are adopted to characterize the synthesized samples. The results show that the yttrium has been successfully incorporated into the zirconia lattice, and the thermal stability of yttrium doped zirconia has been enhanced remarkably.展开更多
Addition of rare earth(RE)such as Y in the surface layer of gray cast iron or Ni-based superalloy by laser sutface melting was carried out using a 2 k W CO_2 laser.For delivering the element Y to the metal surface dur...Addition of rare earth(RE)such as Y in the surface layer of gray cast iron or Ni-based superalloy by laser sutface melting was carried out using a 2 k W CO_2 laser.For delivering the element Y to the metal surface dur- ing laser irradiation,several methods were employed.It is found that Y-containing surface modified layer can he controllably obtained on substrates,a gray cast iron can be laser surface-modified with Cr+Al-Y powder re- sulting in a thin layer of Fe-Cr-Al-Y alloy such as 30Fe40Cr27Al3Y.展开更多
The modification of NaYF4:Yb,Er(Tm) nanoparticles synthesized in the presence of an ionic surfactant is critical to their application in biological fields for better solubility and biocompatibility. In this work, NaYF...The modification of NaYF4:Yb,Er(Tm) nanoparticles synthesized in the presence of an ionic surfactant is critical to their application in biological fields for better solubility and biocompatibility. In this work, NaYF4:Yb,Er(Tm) was transformed from insoluble, inactive to hydrophilic, biocompatible via ligand exchange modification with polyacrylic acid (PAA). Ligand exchange was carried out at room temperature when a colloidal solution of NaYF4:Yb,Er(Tm) in tetrahydrofuran (THF) was treated with excess PAA. The PAA modified NaYF4:Yb,Er(Tm) nanoparticles got better surface properties but with declined inner up-conversion fluorescence. Generally, coating an analogous layer of material outside the core nanoparticles can improve the optical properties of the core. Accordingly, NaYF4:Yb,Er(Tm)/NaYF4 nanoparticles were synthesized before PAA modification to avoid the optical intensity decaying. The result of fluorescence test proved that the water soluble NaYF4:Yb,Er(Tm)/NaYF4/PAA nanocomposites had a sound up-conversion property compared with that of NaYF4:Yb,Er(Tm)/PAA. Furthermore, the up-conversion fluorescence property of the nanocomposite varied with the doping ratio of Er(Tm) to Yb and the possible mechanism for this change was also discussed.展开更多
基金the author(s).This work was financially supported by the National Natural.Science Foundation of China(Nos.51864013 and 52074095)Also,this project supported by National Natural Science Foundation of Guizhou Province with grant No.[2019]1086.
文摘Aluminum oxide inclusions in SWRS82B steel seriously affect the drawing performance of steel strands.The effects of different addition amounts of yttrium(within the range of 0%–0.026%)on the composition,morphology,size and spacing of aluminum oxide inclusions were studied by scanning electron microscopy and energy spectrum analysis.Based on classical thermodynamics and FactSage software,the predominance diagram of inclusions in Fe–O–S–Y system and the effect of the addition of rare earth yttrium on the stability of alumina inclusions were calculated.The results showed that molten steel was modified by adding the rare earth element yttrium.It can be inferred that the approximate route of target inclusion modification was:Al_(2)O_(3)→Y_(2)S_(3)+YAlO_(3)+Al_(2)O_(3)→Y_(2)S_(3)+YAlO_(3)+Y_(2)O_(2)S+YAlO_(3)+Al_(2)O_(3)→Y_(2)S_(3)+Y_(2)O_(2)S.The experimental samples with 0.026%added yttrium had the best inclusion characteristics,in which the inclusion surface density distribution was uniform,and the interfacial distance between inclusions was mainly in the range of 100–500μm.After modification,the average inclusion size in molten steel was reduced by 6.9–8.6μm.The mechanism of yttrium modification was discussed based on actual calculation results and experimental results.
文摘Polystyrene doped with yttrium ethoxide was prepared. The coordination between yttrium atom and benzene ring in the polystyrene doped with yttrium ethoxide was confirmed by means of IR, XPS.
文摘The refinement and modification of Al-Cu alloys can result in the change of solidification process,e.g.the nucleation temperature,eutectic arrest,solidification range and cooling rate.Specially,the refinement and modification of Al-Cu alloy can be achieved by addition of rare earth.In this paper,the effect of yttrium on the microstructure and solidification process of Al-Cu alloys was investigated by the method of thermal analysis.Meanwhile,the microstructure of Al-Cu alloy was observed by OM and SEM.The results show that θ(Al2Cu) phases change from mesh structure into fish-bone shape.Analysis indicates that yttrium causes a depression of solid-liquid coexistence zone and the disappearance of recalescence of the eutectic arrest.
基金Project supported bythe National Nature Science Foundation of China (20276015)
文摘Y-Modified USY was prepared by ion exchange of USY slurry with 0.01 mol·L-1 Y(NO3)3. Phosphotungstic acid (HPW) catalyst supported on USY and Y-USY was prepared by an impregnation method. The materials were characterized by NH3-TPD, XRD, and N2 adsorption. The activity for the removal of thiophene was examined in a three-necked flask. The sulfur content of model compound was tested on WK-2D microcoulometric detector. The effect of yttrium and HPW content, reaction temperature and catalysts, activation temperature on the activity of catalysts were investigated. It was shown that the oxidation activity of thiophene decreased with the increase of Y content except for the catalyst of Y 5%. HPW content had limit influence on activity of catalysts. The optimal reaction temperature and activation temperature were 40 and 320 ℃, respectively.
文摘The modification of corrosion resistance in aqueous solution on 304L austenitic stainless steel by yttrium implantation was studied by electrochemical measurement and surface analysis.The results showed that corrosion resistance of yttrium-implanted samples had been significantly improved. After implantation the free corrosion current and passive current density in sulphuric acid solution were reduced to 1/4～ 1/6 of that of blank samples, and the breakdown potential in chloride contained solution was raised by 30～50 mV. By AES analysis it was found that yttrium was homogeneously distributed in implanted layer as over-saturated solid solution. The ratio of chromium to iron content and the thickness of oxygen-contained layer increased in implanted layer. It was clearly that surface alloying, which modified the surface composition of steel, played an important part in the improvement of corrosion resistance, resulted from the improvement on the property of passivity film of implanted samples.
基金Supported by the Key High-level Scientific and Technical Project of Fujian Department of Science and Technology (2004H008)
文摘Recently, more and more interest has been focused on zirconia for its unique characteristics. In this paper, via the preceding preparation technique, yttrium can be successfully incorporated into nano-zirconia by a cationic surfactant-assisted route. The methods of XRD, TEM, EDS, Uv-vis and N2 adsorption-desorption are adopted to characterize the synthesized samples. The results show that the yttrium has been successfully incorporated into the zirconia lattice, and the thermal stability of yttrium doped zirconia has been enhanced remarkably.
基金Project supported by the National Natural Science Foundation of China
文摘Addition of rare earth(RE)such as Y in the surface layer of gray cast iron or Ni-based superalloy by laser sutface melting was carried out using a 2 k W CO_2 laser.For delivering the element Y to the metal surface dur- ing laser irradiation,several methods were employed.It is found that Y-containing surface modified layer can he controllably obtained on substrates,a gray cast iron can be laser surface-modified with Cr+Al-Y powder re- sulting in a thin layer of Fe-Cr-Al-Y alloy such as 30Fe40Cr27Al3Y.
文摘The modification of NaYF4:Yb,Er(Tm) nanoparticles synthesized in the presence of an ionic surfactant is critical to their application in biological fields for better solubility and biocompatibility. In this work, NaYF4:Yb,Er(Tm) was transformed from insoluble, inactive to hydrophilic, biocompatible via ligand exchange modification with polyacrylic acid (PAA). Ligand exchange was carried out at room temperature when a colloidal solution of NaYF4:Yb,Er(Tm) in tetrahydrofuran (THF) was treated with excess PAA. The PAA modified NaYF4:Yb,Er(Tm) nanoparticles got better surface properties but with declined inner up-conversion fluorescence. Generally, coating an analogous layer of material outside the core nanoparticles can improve the optical properties of the core. Accordingly, NaYF4:Yb,Er(Tm)/NaYF4 nanoparticles were synthesized before PAA modification to avoid the optical intensity decaying. The result of fluorescence test proved that the water soluble NaYF4:Yb,Er(Tm)/NaYF4/PAA nanocomposites had a sound up-conversion property compared with that of NaYF4:Yb,Er(Tm)/PAA. Furthermore, the up-conversion fluorescence property of the nanocomposite varied with the doping ratio of Er(Tm) to Yb and the possible mechanism for this change was also discussed.
