The cathodic electrode process of Y^(3+) ions on the Mo electrode in the LiCl-KCl molten salt with YCl_3(3wt%) in the temperature range of 450～530℃ has been investigated using cyclic voltammetry and chronopotentiome...The cathodic electrode process of Y^(3+) ions on the Mo electrode in the LiCl-KCl molten salt with YCl_3(3wt%) in the temperature range of 450～530℃ has been investigated using cyclic voltammetry and chronopotentiometry.The convolution technique has been applied to the treatment of cyclic voltammogram.The results show that the reduction mechanism of Y^(3+) ion is Y^(3+)+3e=Y,a simple one-step process.The cathodic process is very close to a reversible process under lower scanning rates,and is diffusion-controlled.The cathodic product is an insoluble product.展开更多
Microstructure and oxidation behavior of modified Ni-16Mo-7Cr-4Fe alloys by yttrium microalloying were investigated by scanning electron microscopy, transmission electron microscopy, grazing incident Xray diffraction ...Microstructure and oxidation behavior of modified Ni-16Mo-7Cr-4Fe alloys by yttrium microalloying were investigated by scanning electron microscopy, transmission electron microscopy, grazing incident Xray diffraction and synchrotron radiation X-ray fluorescence. M6 C and Ni17Y2 phases were observed and the amount of Ni17Y2 increased with yttrium concentration. When the yttrium concentration increased to 0.43 wt.%,some Ni17Y2 chains and multi phase regions containing Ni17Y2, M6 C and γ phase appeared, which is harmful for the oxidation resistance. The alloy containing 0.05 wt.% yttrium showed the best oxidation resistance, which derives its oxidation resistance from the adequate concentration of yttrium in the solid-solution(γ phase), the formation of the protective layer of YCr O3 and chromia oxide and the strengthening effect of yttrium on oxide boundaries.展开更多
目的研究一种绿色环保的表面处理方法,以提高镁合金的耐蚀性。方法采用化学浸泡法,以硝酸钇为成膜物质,在AZ31B镁合金表面成功制备一种新型稀土盐转化膜,并以氧化石墨烯为阻隔剂对该转化膜进行复合掺杂。采用扫描电镜(SEM)对膜层的表面...目的研究一种绿色环保的表面处理方法,以提高镁合金的耐蚀性。方法采用化学浸泡法,以硝酸钇为成膜物质,在AZ31B镁合金表面成功制备一种新型稀土盐转化膜,并以氧化石墨烯为阻隔剂对该转化膜进行复合掺杂。采用扫描电镜(SEM)对膜层的表面形貌进行观察,采用析氢实验和电化学测试对不同试样在3.5%Na Cl溶液中的耐蚀性进行了研究。结果镁合金钇盐转化膜表面平整均一,覆盖良好。氧化石墨烯掺杂后的钇盐膜层表面出现了大小不均一的瘤状物质,膜层完整,未出现裂痕。析氢实验结果显示,经过处理的转化膜试样可以极大地抑制腐蚀反应的发生。由极化曲线可知,钇盐转化膜的存在使镁合金的腐蚀电位发生了明显正移,正移了150 m V;而氧化石墨烯掺杂的钇盐膜层的腐蚀电位相对于掺杂前变化不大,但其腐蚀电流密度是掺杂前的1/28。电化学交流阻抗谱的测试结果显示,氧化石墨烯掺杂钇盐转化膜的电荷转移电阻最大,Rct为2485?·cm2;钇盐转化膜的电荷转移电阻次之,Rct为1224?·cm2。两者的电荷转移电阻相对于未经处理的镁合金都有明显提升。结论钇盐转化膜可以明显提高AZ31B镁合金的耐蚀性,氧化石墨烯的加入可以进一步提高转化膜层的耐蚀性。展开更多
Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ ...Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ and Y3+was deposited more prior than other ions during cyclic voltammetry and potential step measurement at 1050 °C.Voltammograms showed Mg2+ could be deposited at-0.5 V,and Y3+ could be deposited at-0.7 V on tungsten electrode compared with platinum electrode.The sedimentation of Mg2+ was more positive about 230 mV than that of other ions in electrolyte.The electrolytic codeposition of yttrium and magnesium was 0.58 V on condition that the weight ratio of Y2O3/MgO was 4:1.Chronopotentiogram indicated that the process of electrodeposition of magnesium-yttrium alloys on tungsten electrode was controlled by diffusion of ions from electrolyte to electrode interface.It was feasible to prepare Magnesium-Yttrium alloys by controlling content of ions in molten salt electrolyte.展开更多
The equilibrium solubility of one CsCl-YCl3-H2O ternary section of CsCl-YCl3-9.5%HCl-H2O quaternary sys-tem at T=298.15 K was investigated by the physico-chemical analysis method and the corresponding phase dia-gram w...The equilibrium solubility of one CsCl-YCl3-H2O ternary section of CsCl-YCl3-9.5%HCl-H2O quaternary sys-tem at T=298.15 K was investigated by the physico-chemical analysis method and the corresponding phase dia-gram was plotted. The crystallization of two new double salts Cs4YCl710H2O (4∶1 type) and Cs3Y2Cl914H2O (3∶2 type) was successful and they were obtained from the complicated system directly. Both were identified and characterized by X-ray, thermal analysis method of TG-DTG, DSC. The fluorescence experiments show that up-conversion phenomenon does not exist in compounds Cs4YCl7·0H2O and Cs3Y2Cl9·4H2O.展开更多
基金This project is supported by the National Natural Science Foundation of China
文摘The cathodic electrode process of Y^(3+) ions on the Mo electrode in the LiCl-KCl molten salt with YCl_3(3wt%) in the temperature range of 450～530℃ has been investigated using cyclic voltammetry and chronopotentiometry.The convolution technique has been applied to the treatment of cyclic voltammogram.The results show that the reduction mechanism of Y^(3+) ion is Y^(3+)+3e=Y,a simple one-step process.The cathodic process is very close to a reversible process under lower scanning rates,and is diffusion-controlled.The cathodic product is an insoluble product.
基金Supported by the program of International S&T Cooperation(No.2014D FG60230)the National Natural Science Foundation of China(Nos.51371189 and 51371188)+1 种基金Science and Technology Commis sion of Shanghai Municipality(No.11JC1414900)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Microstructure and oxidation behavior of modified Ni-16Mo-7Cr-4Fe alloys by yttrium microalloying were investigated by scanning electron microscopy, transmission electron microscopy, grazing incident Xray diffraction and synchrotron radiation X-ray fluorescence. M6 C and Ni17Y2 phases were observed and the amount of Ni17Y2 increased with yttrium concentration. When the yttrium concentration increased to 0.43 wt.%,some Ni17Y2 chains and multi phase regions containing Ni17Y2, M6 C and γ phase appeared, which is harmful for the oxidation resistance. The alloy containing 0.05 wt.% yttrium showed the best oxidation resistance, which derives its oxidation resistance from the adequate concentration of yttrium in the solid-solution(γ phase), the formation of the protective layer of YCr O3 and chromia oxide and the strengthening effect of yttrium on oxide boundaries.
文摘目的研究一种绿色环保的表面处理方法,以提高镁合金的耐蚀性。方法采用化学浸泡法,以硝酸钇为成膜物质,在AZ31B镁合金表面成功制备一种新型稀土盐转化膜,并以氧化石墨烯为阻隔剂对该转化膜进行复合掺杂。采用扫描电镜(SEM)对膜层的表面形貌进行观察,采用析氢实验和电化学测试对不同试样在3.5%Na Cl溶液中的耐蚀性进行了研究。结果镁合金钇盐转化膜表面平整均一,覆盖良好。氧化石墨烯掺杂后的钇盐膜层表面出现了大小不均一的瘤状物质,膜层完整,未出现裂痕。析氢实验结果显示,经过处理的转化膜试样可以极大地抑制腐蚀反应的发生。由极化曲线可知,钇盐转化膜的存在使镁合金的腐蚀电位发生了明显正移,正移了150 m V;而氧化石墨烯掺杂的钇盐膜层的腐蚀电位相对于掺杂前变化不大,但其腐蚀电流密度是掺杂前的1/28。电化学交流阻抗谱的测试结果显示,氧化石墨烯掺杂钇盐转化膜的电荷转移电阻最大,Rct为2485?·cm2;钇盐转化膜的电荷转移电阻次之,Rct为1224?·cm2。两者的电荷转移电阻相对于未经处理的镁合金都有明显提升。结论钇盐转化膜可以明显提高AZ31B镁合金的耐蚀性,氧化石墨烯的加入可以进一步提高转化膜层的耐蚀性。
基金Project supported by the National Natural Science Foundation of China (5076403)
文摘Electrodeposition of magnesium-yttrium alloys from molten salts was studied by electrochemical techniques.LiF-YF3 was electrolyte system with magnesium oxide and Yttrium oxide as raw materials.It was proved that Mg2+ and Y3+was deposited more prior than other ions during cyclic voltammetry and potential step measurement at 1050 °C.Voltammograms showed Mg2+ could be deposited at-0.5 V,and Y3+ could be deposited at-0.7 V on tungsten electrode compared with platinum electrode.The sedimentation of Mg2+ was more positive about 230 mV than that of other ions in electrolyte.The electrolytic codeposition of yttrium and magnesium was 0.58 V on condition that the weight ratio of Y2O3/MgO was 4:1.Chronopotentiogram indicated that the process of electrodeposition of magnesium-yttrium alloys on tungsten electrode was controlled by diffusion of ions from electrolyte to electrode interface.It was feasible to prepare Magnesium-Yttrium alloys by controlling content of ions in molten salt electrolyte.
基金Project supported by the National Natural Science Foundation of China (No. 29371023).
文摘The equilibrium solubility of one CsCl-YCl3-H2O ternary section of CsCl-YCl3-9.5%HCl-H2O quaternary sys-tem at T=298.15 K was investigated by the physico-chemical analysis method and the corresponding phase dia-gram was plotted. The crystallization of two new double salts Cs4YCl710H2O (4∶1 type) and Cs3Y2Cl914H2O (3∶2 type) was successful and they were obtained from the complicated system directly. Both were identified and characterized by X-ray, thermal analysis method of TG-DTG, DSC. The fluorescence experiments show that up-conversion phenomenon does not exist in compounds Cs4YCl7·0H2O and Cs3Y2Cl9·4H2O.
