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Effects of Er^(3+)doping on structure and thermal properties of(Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7)ceramics for thermal barrier coating

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Journal of Rare Earths 2022年第12期40卷 1920-1926,I0004页

作者： Min Xie Shengli An xiwen song Jinxiao Bao Fen Zhou School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010China Inner Mongolia Key Laboratory of Advanced Ceramic Materials and Devices Baotou 014010China

Rare earth Er^(3+)doped(Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7)(x=0.1,0.2,and 0.3)ceramic samples were synthesized using a solid state reaction *** microstructure and thermal properties of these ceramics were investigated to evaluate their potential as thermal barrier coating *** results show that ceramics are compact with regular-shaped grains of 1-5μm size.(Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7)has a pyrochlore structure mainly determined by ionic radius ratio,but the ordering degree decreases with increase of the Er_(2)O_(3)*** is no phase transformation from 1000 to 1200℃,and the(Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7)ceramics exhibit excellent phase stability during thermal treatment at 1200℃for 100 h and 1400℃for 50 *** thermal conductivities of dense(Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7)ceramics range from 1.52 to 1.59 W/(m·K),which is lower than that of Sm_(2)Zr_(2)O_(7),and decrease as the Er2O3content ***,the thermal expansion coefficient of(Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7)is higher than that of Sm_(2)Zr_(2)O_(7).

关键词： (Sm_(1-x)Er_(x))_(2)Zr_(2)O_(7) Pyrochlore structure Thermal-physical properties Er^(3+)doping Rare earths

Effect of Nb^(5+)and Cu^(2+)codoping on thermal properties of Gd_(2)Zr_(2)O_(7)ceramic

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Journal of Rare Earths 2021年第2期39卷 180-185页

作者： Tao Jiang Min Xie Lili Guan Xuanli Wang xiwen song School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010China

In this work,Nb^(5+)and Cu^(2+)were selected to partially substitute Zr4+in Gd_(2)Zr_(2)O_(7)for studying the phase structure,microscopic morphology and thermal ***_(2)(Zr_(1-3 x/2)Nb_(x)CU_(x/2))_(2)O_(7)(x=0,0.05,0.1,0.15,0.2,0.25)ceramic materials were synthesized by high-temperature solid-state reaction *** results show that the Gd_(2)(Zr_(1-3 x/2)Nb_(x)Cu_(x)/2)_(2)O_(7)ceramics present cubic pyrochlore structure with clear grain boundaries and dense cell *** the thermal expansion coefficient of Gd_(2)(Zr_(1-3 x/2)Nb_(x)Cu_(x/2))_(2)O_(7)ceramics gradually decreases because of the incorporation of Nb^(5+)and Cu^(2+)into Zr-site in Gd_(2)Zr_(2)O_(7).Meanwhile,its thermal conductivity decreases firstly and then increases with the doping of Nb^(5+)and Cu^(2+),which reaches the lowest value for the composition of Gd_(2)(Zr_(0.85)Nb_(0.1)Cu_(0.05))_(2)O_(7).

关键词： Gd_(2)Zr_(2)O_(7) Co-doping Pyrochlore structure Thermal properties Rare earths

Development of a high-performance green Fe-Al_(2)O_(3)composites using Bayan Obo minerals:Enhancement effects of CeO_(2)

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Journal of Rare Earths 2023年第5期41卷 747-757,I0005页

作者： Yuxin Chen Ning Wang Shengli An Changkun Cai Manyi Xie xiwen song School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010China Inner Mongolia Key Laboratory of Advanced Ceramic Materials and Devices Baotou 014010China Key Laboratory of Green Extraction&Efficient Utilization of Light Rare-Earth Resources Ministry of EducationBaotou 014010China

With the deepening understanding for the concept of sustainable development,the utilization of minerals is no longer limited to the traditional *** this study,an environment friendly method for preparing Fe-Al_(2)O_(3)composites by using natural minerals was ***,the effects of CeO_(2)on the properties of composites were *** mechanical properties of Fe-Al_(2)O_(3)composites prepared by natural minerals are affected by the brittleness of glass *** strength and toughness of the glass phase in the composite are improved successfully by using rare earth oxides,indicating that the natural rare earths in Bayan Obo minerals have an enhanced influence on the properties of composite *** results show that the properties of glass phase can be significantly improved by addition of CeO_(2).At the optimal addition of 3 wt%CeO_(2),the composite achieves the density of 4.21 g/cm^(3),flexural strength of 401 MPa,Vickers hardness of 13.07 GPa and fracture toughness of 6.58 MPa·m^(1/2).The composite has excellent mechanical properties,which can be used in engineering as a cheap structural *** study aims at reducing waste emissions,improving energy efficiencies and avoiding waste of rare earth resources during the preparation of composite materials.

关键词： Cleaner production Natural minerals Alumina matrix composites Energy saving Rare earth oxides

Substituent Influence of Yttria by Gadolinia on the Tetragonal Phase Stability for Y_2O_3-Ta_2O_5-ZrO_2 Ceramics at 1300℃

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Journal of Materials Science & Technology 2014年第4期30卷 381-386页

作者： Xiaoqing Niu Min Xie Fen Zhou Rende Mu xiwen song Shengli An Inner Mongolia Key Laboratory of Advanced Ceramics and Device School of Materials and MetallurgyInner Mongolia University of Science and Technology Beijing Institute of Aeronautical Materials

The influences of equimolar substitution of yttria by gadolinia on the phase constituent and stability for Y203- Ta2Os-Zr02 ceramics have been investigated. The ceramics with the Gd content lower than 8 tool% exhibit pure tetragonal phase as well as high tetragonal phase stability. However, the high Gd containing ceramics consist of t-Zr02, m-Zr02 and monoclinic GdTa04 and show complicated phase evolution behaviors. The fractions of monoclinic Zr02 and GdTa04 increase with increasing Gd content, indicating that the excessive substitution of Gd for Y results in a reduction in the tetragonal phase stability. In addition, the lower Gd containing ceramics show an almost invariable tetragonality, while the higher Gd containing ceramics reveal a composition-dependent tetragonality. Accordingly, an association of the tetragonal phase stability and tetragonality with the Gd concentration is established, which provides us a clue to understand the phase stability of these ceramics.

关键词： Ceramics Zr02 X-ray diffraction Thermal stability

The role of CO_(2)dissociation in CO_(2)hydrogenation to ethanol on CoCu/silica catalysts

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Nano Research 2023年第5期16卷 6128-6133页

作者： Zhongyan Wang Chengsheng Yang Xianghong Li xiwen song Chunlei Pei Zhi-Jian Zhao Jinlong Gong Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

CoCu-based catalysts are widely used in CO_(x) hydrogenation reactions to produce higher alcohols due to the C–C coupling ability of Co and the ability of Cu to produce *** work describes the role of easily happened CO_(2)dissociation on the CoCu surface during the reaction,using different silica support to tune the metal–support interaction,reaches different selectivity to *** supported on mesoporous silica MCM-41 shows ethanol selectivity as high as 85.3%,the ethanol space-time yield(STY)is 0.229 mmol/(gmetal∙h),however,poor selectivity to ethanol as low as 28.8%is observed on CoCu supported on amorphous *** different selectivity is due to the different intensities of CO_(2)dissociation on the *** adsorbed O*produced via CO_(2)dissociation can occupy the cobalt hollow sites on CoCu surfaces,which are also the adsorption sites of C1 intermediates for further C–C coupling.

关键词： CO_(2)hydrogenation bimetallic catalysts cobalt catalysts CO_(2)dissociation ethanol synthesis

Study on rare earth/alkaline earth oxide-doped CeO_2 solid electrolyte

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Rare Metals 2007年第4期26卷 311-316页

作者： YAN Kai ZHEN Qiang song xiwen School of Materials Science and Engineering Shanghai University Shanghai 200072 China Research Center of Nanoscience and Nanotechnology Shanghai Univeesity Shanghai 200444 China School of Materials Science and Engineering Inner Mongolia University of Science and Technology B aotou 014010 China

Five types of rare earth/alkaline earth oxide-doped CeO2 superfine-powders were synthesized by a low-temperature combustion technique. The relevant solid electrolyte materials were also sintered by pressureless sintering at different temperatures. The results of X-ray diffraction and transmission electron microscopy showed that the grain size of the powders was approximately 20-30 nm, and rare earth/alkaline earth oxides were completely dissolved into ceria-based solid solution with fluorite structure. The electrical conductivities of the SmzO3-CeO2 system were measured by the ac impedance technique in air at temperatures ranging from 513-900℃. The results indicated that the ionic conductivities of Srno.2oCe0.8Ol.875 solid electrolyte increase with increasing sintering temperature, and the relationship between the conductivities and measuring temperature obeys the An＇henius equation. Then the SmzO3-CeO2 material was further doped with other rare earth/alkaline earth oxide, and the conductivities improve with the effective index.

关键词： doped ceria rare earth/alkaline earth oxide solid electrolyte conductivity effective index

Synthesis and Characterization of Sm_xGd_yCe_(1-x-y)O_(2-δ) Nanopowders

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Journal of Materials Science & Technology 2005年第1期21卷 131-134页

作者： xiwen song, Yongwang ZHAO, Zhefeng WANG, Jun PENG,Wenguang ZHAO and Shengli AN School of Materials Science and Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaAssoc. Prof. Sch. of Mat. Sci. and Eng. Inner Mongolia Univ. of Sci. Baotou 014010 China Sch. of Metall. and Ecological Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

SmxGdyCe1-x-yO2-δ (x+y=0.2 and x=0, 0.04, 0.08, 0.12, 0.16, 0.2) nanopowders were prepared by a copre-cipitation method. The zeta potential and sedimentation volume of Ce(OH)4 aqueous dispersions at different pH values were measured. The isoelectric point (IEP) of Ce(OH)4 suspensions is 7.0. The maximum potential value of -18.5 mV and maximum sedimentation volume of 19 ml are reached at pH=10. The evolution behaviors of the xSm(OH)3·yGd(OH)3·(1-x-y)Ce(OH)4 dried powders in the heating process was characterized by DTA/TG and XRO. The powders decompose to ceria based solid solution at a temperature below 300℃ and forms cubic fluorite structure ceria at about 650℃. The properties of SmxGdyCe1-x-yO2-δ solid solutions were characterized by XRD, TEM and BET. The lattice parameter of doped Ce02 increases linearly with increasing Sm3+ substitution (or decreasing Gd3+ substitution). The particle size of the doped ceria powders is from 5 nm to 10 nm.

关键词： Coprecipitation Sm2O3 Gd2O3 Doped Ceria Nano-powders

Mn掺杂对(Y_(0.4)Er_(0.6))_(3)Al_(5)O_(12)热障涂层材料的微观结构和导热性能的影响

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材料研究学报 2024年第6期38卷 463-470页

作者：王俊王炫力刘爽宋蕊宋希文内蒙古科技大学材料科学与工程学院包头014010

采用固相合成法制备(Y_(0.4)Er_(0.6))_(3)(Al_(1-y)Mn_(y))5O12(y=0,0.02,0.04,0.06,0.08,0.1)陶瓷材料,使用X射线衍射仪及Rietveld精修、X射线光电子能谱仪、扫描电子显微镜、X射线能谱仪、透射电子显微镜和激光导热仪等手段对其表征... 详细信息

采用固相合成法制备(Y_(0.4)Er_(0.6))_(3)(Al_(1-y)Mn_(y))5O12(y=0,0.02,0.04,0.06,0.08,0.1)陶瓷材料,使用X射线衍射仪及Rietveld精修、X射线光电子能谱仪、扫描电子显微镜、X射线能谱仪、透射电子显微镜和激光导热仪等手段对其表征,研究了Mn掺杂对其微观结构和导热性能的影响。结果表明:(Y_(0.4)Er_(0.6))_(3)(Al_(1-y)Mn_(y))5O12陶瓷材料均为单一的YAG相,随着Mn掺杂量的提高晶格常数和晶胞体积先减小后增大,Mn2+逐渐占据晶胞中的Al3+位置但是Y_(3)Al_(5)O_(12)的晶体结构不变;Mn掺杂使(Y_(0.4)Er_(0.6))_(3)(Al_(1-y)Mn_(y))5O12陶瓷材料的热导率显著降低,y=0.06的陶瓷材料热导率最低,在1100℃热导率约为1.38 W/(m·K),比纯YAG陶瓷的热导率(2.1 W/(m·K))降低了约34.6%。

关键词：无机非金属材料热障涂层钇铝石榴石双位掺杂微观结构热导率

Impedance Characteristics of MgO-ZrO_2 Ceramics Doped with CeO_2

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Journal of Rare Earths 2006年第2期24卷 201-201页

作者： Zhao Wenguang An Shengli song xiwen School of Materials and Metallurgy Inner Mongolia University of Science and Technology Baotou 014010 China

The ultrafine CexMg0.06Zr1-xO1.94 （ x = 0 16% ） powders were synthesized by a chemical co-precipitated method. The pressed compacts were sintered in air at 1300, 1400, 1500, 1600℃ for 3 h, respectively. The phase of the ceramics was characterized by the X-ray diffraction （XRD） method. The conductivity of the ceramics was measured by the AC complex impedance technique at 700- 1200 ℃. The ratio of the cubic phase in the ceramics improves with increasing CeO2 content, leading to a enlargement of the oxygen ionic migration channel. The contact resistance between conductive phase particles decreases with increasing CeO2 content, leading to a lower migration hindrance of the oxygen ionic. Consequently, the ionic conductivity of the ceramics improves with increas- ing CeO2 content. Additionally, an analysis for this phenomenon was also presented.

关键词： inorganic nonmetallic materials CexMg0.06Zr1-xO1.94 ceramics AC complex impedance ionic conductivity activation energy for conduction rare earths