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Combustion synthesis of Hf-doped zirconolite-rich composite waste forms and the aqueous durability

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先进陶瓷（英文） 2019年第3期8卷 448-455页

作者： kuibao zhang Dan YIN Zongsheng HE Baozhu LUO Haibin zhang State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang621010China National Defense Key Discipline Lab of Nuclear Waste and Environmental Safety Southwest University of Science and TechnologyMianyang621010China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang621900China

Zirconolite is recognized as one of the most durable waste matrices for the disposal of high-level radioactive wastes(HLWs).In this study,HfO2 was employed as the surrogate of tetravalent ***-bearing zirconolite-based composite waste forms(CaZr1–xHfxTi2O7)were rapidly prepared by combustion synthesis(CS)using CuO as the oxidant,where quick pressing(QP)was introduced to obtain densified *** as solid state reaction process,the Zr site of zirconolite can be totally occupied by Hf(x=1.0)under the CS *** original 2M zirconolite structure was maintained and a small amount of perovskite impurity phase was generated in the final *** aqueous durability of representative sample(Cu-Hf-0.6)was tested,where the 42-day normalized leaching rates(LRi)of Ca,Cu,and Hf are 0.25,3.10×10–2,and 1.11×10–8 g·m–2·d–1.

关键词： combustion synthesis(CS) nuclear waste HfO2 zirconolite aqueous durability

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硅改性酚醛树脂物理性能的分子动力学模拟

计算物理 2024年第3期41卷 345-356页

作者：许铋立景昭刘骁代波姬广富张魁宝葛妮娜西南科技大学环境友好能源材料国家重点实验室四川绵阳621010 北京航天长征飞行器研究所北京100076 中国空气动力研究与发展中心四川绵阳621000 中国工程物理研究院流体物理研究所四川绵阳621900

采用分子动力学模拟方法研究纳米SiO2以及甲基苯基二甲氧基硅烷改性酚醛树脂的物理性能。研究表明:300 K下未改性酚醛树脂玻璃转化温度为362 K,弹性模量、剪切模量分别为5.45 GPa和2.19 GPa,热导率和热膨胀系数分别为0.37 W·(m·k)-1和... 详细信息

采用分子动力学模拟方法研究纳米SiO2以及甲基苯基二甲氧基硅烷改性酚醛树脂的物理性能。研究表明:300 K下未改性酚醛树脂玻璃转化温度为362 K,弹性模量、剪切模量分别为5.45 GPa和2.19 GPa,热导率和热膨胀系数分别为0.37 W·(m·k)-1和3.8×10-5 K-1,添加纳米SiO2后玻璃转化温度提高了1.6%,弹性模量、剪切模量分别提高了34.9%和28.8%,热导率和热膨胀率分别降低了11%和31.6%。SiO2表面接枝3%、5%、7%和10%硅烷偶联剂以及甲基苯基二甲氧基硅烷改性酚醛树脂玻璃转化温度分别提高了10.5%、15.2%、16.8%、19.3%和1.5%,弹性模量分别提高了44.4%、53.2%、53.8%、63.5%和13.4%,而热导率分别降低了12.4%、13.5%、11.2%、7%和10%。此外甲基苯基二甲氧基硅烷改性的酚醛树脂的热膨胀系数较未改性酚醛树脂提高15.7%。研究表明:掺杂纳米SiO2、SiO2表面接枝硅烷偶联剂以及甲基苯基二甲氧基硅烷改性都能够提高酚醛树脂的玻璃转化温度,机械性能同时降低热导率,而对于热膨胀系数,纳米SiO2掺杂使其减小,甲基苯基二甲氧基硅烷改性则会使其明显增大。

关键词：硅改性酚醛树脂玻璃转化温度热导率力学性能分子动力学模拟

Combustion synthesis and characterizations of Sm2O3 doped zirconolite-rich waste forms with CuO as oxidant

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Journal of Rare Earths 2019年第12期37卷 1359-1365页

作者： kuibao zhang Dan Yin Zongsheng He Jiali Xue Wenwen Zhao Haibin zhang State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010China National Defense Key Discipline Lab of Nuclear Waste and Environmental Safety Southwest University of Science and TechnologyMianyang 62W10China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China

Zirconolite is one of the most important matrix materials for nuclear waste *** this study,Sm was employed as the surrogate of trivalent ***-doped zirconolite-rich waste forms were readily prepared by combustion synthesis(CS)using CuO as the *** different schemes with or without Al2O3 as the charge compensator were carried out *** results demonstrate that Al2O3 addition results in complex phase *** the other hand,the samples without Al2O3 addition show desirable products of zirconolite and *** EDX analysis shows that Sm is concurrently incorporated into the Ca and Zr sites of zirconolite,which transforms to pyrochlore structure with high Sm2O3 *** aqueous durability of representative Sm-doped sample(Sm-0.6)was *** 42 days normalized leaching rate of Sm is as low as 6.41×10-7 g/(m2 d),which exhibits high durability of Sm-doped sample.

关键词： Combustion synthesis Sm2O3 Zirconolite Pyrochlore Aqueous durability Rare earths

Solid-state reaction synthesis and chemical stability studies in Nd-doped zirconolite-rich ceramics

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Journal of Rare Earths 2018年第5期36卷 492-498页

作者： Dan Yin kuibao zhang Le Peng Zongsheng He Yuan Liu Haibin zhang Xirui Lu State Key Laboratory Cultivation Base for Nonmetal Composite and Foundational Materials Southwest University of Science and Technology Mianyang 621010 China National Defense Key Discipline Lab of Nuclear Waste and Environmental Safety Southwest University of Science and Technology Mianyang 621010 China Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China

In this study, Nd-bearing zirconolite-rich ceramics were prepared by solid-state reaction process using CaF2,ZrO2, Ti,TiO2, Fe2 O3 and Nd2O3 as the raw materials. Neodymium was used as trivalent actinide surrogate and designed to substitute the Ca and Zr sites of zirconolite with general stoichiometry of Ca1-xZr1-xNd2 xTi2O7（0≤x≤0.3）. Density of Fe-Nd-O sample reaches a maximum value of 4.13 g/cm^2 after being sintered at 1325 ℃ for 42 h. Three major phases, namely zirconolite, perovskite and pseudobrookite, are observed in all these samples. The EDX result shows that Nd2O3 can be successfully incorporated into the lattice structure of the prepared zirconolite-rich minerals and replace the Ca sites of zirconolite and perovskite with Fe3＋ as the charge-compensating ion. Furthermore, the thermal conductivities are all in the range of 1.51-1.67 W/（m·K）. The normalized elemental leaching rates of Ca and Nd in the Fe-Nd-0.2 sample keep in low values of 6.20 × 10^-2 and 4.86 × 10^-4 g/（m^2·d） after 42 d.

关键词： Zirconolite Perovskite Pseudobrookite Nd2O3 Chemical stability Rare earths

Synthesis,microstructure,and properties of high purity Mo_(2)TiAlC_(2) ceramics fabricated by spark plasma sintering

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Journal of Advanced Ceramics 2020年第6期9卷 759-768页

作者： Yunhui NIU Shuai FU kuibao zhang Bo DAI Haibin zhang Salvatore GRASSO Chunfeng HU State Key Laboratory of Environment-Friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010China Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China

The synthesis,microstructure,and properties of high purity dense bulk Mo_(2)TiAlC_(2) ceramics were *** purity Mo_(2)TiAlC_(2) powder was synthesized at 1873 K starting from Mo,Ti,Al,and graphite powders with a molar ratio of 2:1:1.25:*** synthesis mechanism of Mo_(2)TiAlC_(2) was explored by analyzing the compositions of samples sintered at different *** was found that the Mo_(2)TiAlC_(2) phase was formed from the reaction among Mo3Al2C,Mo2C,TiC,and *** Mo_(2)TiAlC_(2) bulk sample was prepared by spark plasma sintering(SPS)at 1673 K under a pressure of 40 *** relative density of the dense sample was 98.3%.The mean grain size was 3.5μm in length and 1.5μm in *** typical layered structure could be clearly *** electrical conductivity of Mo_(2)TiAlC_(2) ceramic measured at the temperature range of 2-300 K decreased from 0.95×10^(6) to 0.77×10^(6)Ω^(-1)·m^(-1).Thermal conductivity measured at the temperature range of 300-1273 K decreased from 8.0 to 6.4 W·(m·K)^(-1).The thermal expansion coefficient(TEC)of Mo_(2)TiAlC_(2) measured at the temperature of 350-1100 K was calculated as 9.0×10^(-6) K^(-1).Additionally,the layered structure and fine grain size benefited for excellent mechanical properties of low intrinsic Vickers hardness of 5.2 GPa,high flexural strength of 407.9 MPa,high fracture toughness of 6.5 MPa·m^(1/2),and high compressive strength of 1079 *** at the indentation load of 300 N,the residual flexural strength could hold 84% of the value of undamaged one,indicating remarkable damage ***,it was confirmed that Mo_(2)TiAlC_(2) ceramic had a good oxidation resistance below 1200 K in the air.

关键词： MAX phase Mo_(2)TiAlC_(2) synthesis microstructure properties

Self-propagating high-temperature synthesis of ZrO_2 incorporated Gd_2Ti_2O_7 pyrochlore

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Journal of Advanced Ceramics 2018年第1期7卷 41-49页

作者： Le PENG kuibao zhang Zongsheng HE Dan YIN Jiali XUE Chen XU Haibin zhang State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials Southwest University of Science and Technology Science and Technology on Surface Physics and Chemistry Laboratory China Academy of Engineering Physics Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics

In this research, Zr-doped Gd_2Ti_2O_7 pyrochlores, with the composition of Gd_2(Ti_(1-x)Zr_x)_2O_7, were firstly synthesized by self-propagating high-temperature synthesis plus quick pressing(SHS/QP) using CuO as the oxidant and Ti as the reductant. To improve the radiation resistance of titanate–pyrochlore, up to 35 at% Zr was incorporated to substitute the Ti site of Gd_2Ti_2O_7 pyrochlore(Gd_2(Ti_(0.75)Zr_(0.35))_2O_7). XRD and SEM microstructural characterizations showed the formation of a composite ceramic with the major pyrochlore phase and the minor Cu phase. The generated temperature of samples decreased from 1702to 1011 ℃ with increasing Zr content. The effects of sintering temperature and pressure time on phase composition and microstructure were systematically studied. Besides, the influence of thermal transmission on the whole combustion process was also explored. The pyrochlore-based waste form possessed high bulk density of 6.25 g/cm^3 and Vickers hardness of 10.81 GPa. The MCC-1 leaching test showed the normalized elemental leaching rates(42d) of Cu, Gd, and Zr are 1.27×10^(-2), 1.33×10^(-3), and 8.44×10^(-7)g·m^(-2)·d^(-1), respectively.

关键词： self-propagating high-temperature synthesis plus quick pressing (SHS/QP) pyrochlore thermal transmission waste form aqueous leachability

有机硅改性酚醛树脂气凝胶及其复合材料的制备与性能

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西南科技大学学报 2024年第3期39卷 1-8,41页

作者：邵忠武张魁宝周琳李博王春雅张军西南科技大学环境友好能源材料国家重点实验室四川绵阳621010 中国空气动力研究与发展中心四川绵阳621000

纤维增强酚醛树脂气凝胶复合材料由于其低密度、低导热和优异的热稳定性而在高温热防护领域备受关注。为满足日益苛刻的热防护服役环境,通过水解法原位共聚将硅烷链段引入酚醛树脂,制备了一种具有优异抗氧化和耐烧蚀性能的硅改性酚醛气... 详细信息

纤维增强酚醛树脂气凝胶复合材料由于其低密度、低导热和优异的热稳定性而在高温热防护领域备受关注。为满足日益苛刻的热防护服役环境,通过水解法原位共聚将硅烷链段引入酚醛树脂,制备了一种具有优异抗氧化和耐烧蚀性能的硅改性酚醛气凝胶,并将其与石英纤维复合,得到纤维增强杂化酚醛气凝胶复合材料。性能测试表明:在1300℃丁烷火焰下处理15 s后,纤维增强杂化酚醛气凝胶复合材料质量烧蚀率为0.0879 g/s,线性烧蚀率为0.0347 mm/s,对比纯酚醛气凝胶复合材料分别下降了52.0%和15.6%;在40 kW石英灯下加热20 min后,质量烧蚀率为0.230 g/min,线性烧蚀率为0.051 mm/min,对比纯酚醛气凝胶复合材料分别下降了57.9%和67.3%。结果显示硅烷链段的引入提高了复合材料的抗氧化性能和耐烧蚀性能,该纤维增强杂化酚醛气凝胶复合材料在航空航天热防护领域具有广阔的应用前景。

关键词：有机硅改性酚醛树脂纤维复合材料热防护

Self-propagating High-temperature Synthesis of Sm and Zr Co-doped Gd2Ti2O7 Pyrochlore Ceramics as Nuclear Waste Forms

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Journal of Wuhan University of Technology(Materials Science) 2021年第2期36卷 196-202页

作者： XIE Dayan zhang kuibao LI Weiwei LUO Baozhu GUO Haiyan State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang 621010China National Defense Key Discipline Lab of Nuclear Waste and Environmental Safety Southwest University of Science and TechnologyMianyang 621010China

We reported a rapid synthesis of Sm^(3+)/Zr^(4+)co-doped Gd2Ti2O7 pyrochlore simulated nuclear wastes solidification by self-propagation plus quick pressing *** increment excess contents of Sm2O3 and ZrO2 from 0 to 10wt%,the phase composition of the products is a mixed phase of pyrochlore structure and defective fluorite structure by X-ray diffraction(XRD)analysis and Raman *** addition,the SEM results demonstrate the fracture surface and microstructure of Gd2Ti2O7-based *** densified pyrochlore waste form exhibits high bulk density of 5.56 g·cm^(-3) and vickers hardness of 11.20±0.2 *** leaching tests show that the elemental leaching rates of Gd,Sm,and Cu after 42 days are 1.92×10^(-4),1.51×10^(-4),and 3.90×10^(-3) g·m^(-2)·d^(-1),respectively.

关键词： SHS pyrochlore immobilization of nuclear wastes excess

Platelet function monitoring guided antiplatelet therapy in patients receiving high-risk coronary interventions

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Chinese Medical Journal 2014年第19期127卷 3364-3370页

作者： Xu Li Wang Lefeng Yang Xinchun Li kuibao Sun Hao zhang Dapeng Wang Hongshi Li Weiming Ni Zhuhua Xia Kun Liu Yu Heart Center Beijing Chaoyang.Hospital CapitalMedicl UniversityBeijing 100020

Background Large-scale clinical trials have shown that routine monitoring of the platelet function in patients after percutanous coronary intervention （PCI） is not necessary. However, it is still unclear whether patients received high-risk PCI would benefit from a therapy which is guided by a selective platelet function monitoring. This explanatory study sought to assess the benefit of a therapy guided by platelet function monitoring for these patients. Methods Acute coronary syndrome （ACS） patients （n=384） who received high-risk, complex PCI were randomized into two groups. PCI in the two types of lesions described below was defined as high-risk, complex PCI： lesions that could result in severe clinical outcomes if stent thrombosis occurred or lesions at high risk for stent thrombosis. The patients in the conventionally treated group received standard dual antiplatelet therapy. The patients in the platelet function monitoring guided group received an antiplated therapy guided by a modified thromboelastography （TEG） platelet mapping： If inhibition of platelet aggregation （IPA） induced by arachidonic acid （AA） was less than 50% the aspirin dosage was raised to 200 mg/d; if IPA induced by adenosine diphosphate （ADP） was less than 30% the clopidogrel dosage was raised to 150 mg/d, for three months. The primary efficacy endpoint was a composite of myocardial infarction, emergency target vessel revascularization （eTVR）, stent thrombosis, and death in six months. Results This study included 384 patients; 191 and 193 in the conventionally treated group and platelet function monitoring guided group, respectively. No significant differences were observed in the baseline clinical characteristics and interventional data between the two groups. In the platelet function monitoring guided group, the mean IPA induced by AA and ADP were （69.2＋24.5）% （range, 4.8% to 100.0%） and （51.4＋29.8）% （range, 0.2% to 100.0%）, respectively. The AA- induced IPA of forty-three （22.2%） patients wa

关键词： platelet function antiplatelet therapy, percutanous coronary intervention, acute coronary syndrome