抗等离子体辐照的防氚渗透材料的研究

本文研究了氚在经能量为１ｋｅＶ和２８ｋｅＶＨ＋离子辐照的３１６Ｌ不锈钢中，及其ＴｉＣ和ＴｉＮ＋ＴｉＣ表面镀层材料中的扩散渗透行为。结果表明，３１６Ｌ不锈钢表面经１ｋｅＶＨ＋离子辐照后，在３５２ｏＣ下氚在其中的渗透率比在有天然氧化膜的３１６Ｌ不锈钢中的渗透率高２４７倍，但只为表面镀钯的３１６Ｌ不锈钢中的渗透率的１／１．６５。３１６Ｌ不锈钢表面镀２—５μｍＴｉＣ，并经化学热处理在ＴｉＣ中生成防氚渗透阻挡层后，在下游面用１ｋｅＶ能量的Ｈ＋离子辐照，在３５９ｏＣ下氚在镀膜中的渗透率比没受辐照的样品的低５５．７％。在３１６Ｌ不锈钢表面镀有ＴｉＮ＋ＴｉＣ的材料中，其涂层的下游面用能量为２８ｋｅＶ的Ｈ＋离子辐照后，在３２６ｏＣ下氚在其中的渗透率比没受辐照的高了２倍。     

不锈钢表面激光熔覆层与喷焊层耐磨性对比研究

本文研究在１Ｃｒ１８Ｎｉ９Ｔｉ基体上采用激光熔覆和离子喷焊二种工艺形成的涂层对耐磨性的影响。使用５ｋＷ横流ＣＯ２激光器对预置在基体上的Ｃｏ基自熔合金粉末进行单道或多道扫描，得到的熔层与等离子焊层对比结果是：激光熔层缺陷率低，成品率高，其结构致密均匀，晶粒细小，成分稀释率更小，对基体热影响小，熔层硬度与强韧性更高。性能试验证明：激光熔层具有更高的抗擦伤磨损和抗冲击滑动高温磨损性能，耐磨性提高了一倍左右。     

氚在锆合金包壳材料中的扩散行为模拟

基于氚扩散基本模型建立了氚扩散行为一维模拟程序,对模拟程序进行了典型实验验证,模拟结果与实验结果符合较好。分析了不同氚浓度、温度分布对锆合金包壳材料中氚的扩散行为的影响。分析结果表明:包壳-芯块间隙内氚浓度的升高会导致进出包壳的氚扩散通量提高,渗透通量增大;由于包壳氧化层相对较低的扩散系数,包壳氧化层的存在对氚渗透有较大的限制作用;温度对氚扩散速率的影响很显著,温度越高,扩散速度越快;锆合金外表面氧化层的相对低温限制了氚渗透出包壳管的速率,温度梯度导致的热致扩散有利于氚向包壳冷测扩散。     

Cr（Ⅵ）离子在TiO2表面的光催化还原机理研究

采用ＸＰＳ和ＥＳＲ表征技术研究表明,Ｃｒ离子在ＴｉＯ２表面的光催化还原过程中,有Ｔｉ＾３＋物种生成并参与了Ｃｒ离子的还原反应。实验结果表明,Ｃｒ离子的光催化还原主要以从Ｔｉ＾３＋上得到离子的间接还原为主,同时也存在着从ＴｉＯ２导带捕获光激发电子发生直接还原的可能性。     

金红石TiO2晶体中F型色心电子结构及其吸收光谱研究

运用Ｆ型色心的类氢离子波函数结合电荷自洽离散变分法,对ＴｉＯ２晶体中Ｆ型色心的电子结构进行了计算,并利用能量最小原理优化了色心格点周围的Ｔｉ,Ｏ离子结构,得到了ＴｉＯ２晶体中Ｆ,Ｆ＋和Ｆ＾２＋心的能带、态「密度,并讨论了色心的光学跃迁模式,计算结构表明,Ｆ,Ｆ＾＋心在ＴｉＯ２晶体的禁带中引入的旋主能级,Ｆ＾２＋心在禁带中引入了浅受主能级,Ｆ和Ｆ＋心的光学跃有分别是０．８５ｅＣ,１．６７ｅＣ,经还原     

多元离子束增强沉积在新型薄膜材料上的应用

采用Ｎ＋＋Ｃｒ＋多元离子束增强沉积合成（ＴｉＣｒ）Ｎ膜层，对膜层进行了ＡＥＳ、ＴＥＭ和ＸＲＤ分析．测试了膜基体系的力学性能和电化学性能．与普通物理气相沉积相比，多元离子束增强沉积显示了开发新型薄膜材料的较强潜力． Multicomponent ion beam enhanced deposition was used to synthesize (TiCr)N films. The films were characterized by AES,TEM and XRD methods. The electrochemical property and mechanics property of the films were measured. The experimental results show that the multicomponent ion beam enhanced deposition has stronger potential of new material development than physical vapour deposition.     

CFETR氦冷固态增殖包层多物理场氚输运分析

针对中国聚变工程实验堆(CFETR)外中平面氦冷固态增殖包层模块,开展了包层热、流、氚的多物理场耦合模拟分析,获得包层模块的氚分布、氚滞留量及氚渗透量。分析结果显示,在包层球床区无因吹洗气体流动滞缓而造成的氚滞留现象,其吹洗气体流道设计合理。同时,开展了入口吹洗气体掺氢量的参数敏感性分析。分析显示吹洗气体掺氢可以降低材料表面氚浓度,从而降低结构材料中的氚浓度梯度,抑制氚渗透;入口氢气浓度从 1ppm 增加到 1000ppm 时,氚渗透量降低为 1/20。     

铁电薄膜底电极对薄膜结构与电性能的影响

研究了电极材料（Ｐｔ／Ｔｉ）对铁电ＰＬＺＴ（７．５／６５／３５）陶瓷薄膜结构和性能的影响．认为在Ｐｔ层厚度一定时，Ｔｉ层的厚度对铁电薄膜的结构和性能有显著影响．当Ｔｉ层过厚或过薄时，铁电薄膜的结构较差；而当Ｔｉ层的厚度适中时，则铁电薄膜的显向下微结构均匀，电性能较好，典型的剩余极化强度和矫顽场分别为２７．８μＣ·ｃｍ^-2和６５．１ｋＶ·ｃｍ^-1． 关键词：     

Ti：Al2O3晶体的电子自旋共振谱研究

Ｔｉ：Ａｌ２Ｏ３晶体中的顺磁中心Ｔｉ＾３＋由于强烈的晶格自旋耦合而使其电子自旋共振吸收只有在液拟温度附近才能看到，本实验在液氮温度附近记录到由许多强的的吸收峰迭加于Ｔｉ＾３＋宽吸收线所组成的电子自旋共振谱，这些吸吸收峰被认为是Ａｌ２Ｏ３基质中的Ｆｅ＾３＋，Ｍｎ＾２＋，Ｃｒ＾３＋，Ｍｏ＾３＋，Ｆｅ＾２＋，Ｃｏ＾２＋等杂质的共振吸收及Ｔｉ＾２＋３Ａ２ｇ基态的双量子跃迁造成的。     

聚脲涂层复合结构抗侵彻机理实验研究

为研究聚脲涂层复合靶板的抗侵彻性能,利用球形弹丸开展了相近面密度下的钢质靶板与喷涂聚脲涂层复合结构的弹道冲击实验,得到了钢靶与采用不同涂覆方式制备的聚脲涂层复合结构的抗侵彻性能,分析了失效模式和吸能机理。结果表明:冲击过程中,前聚脲涂层能有效缓冲弹体与钢靶之间的撞击载荷,使钢靶产生预变形,降低弹体的相对侵彻速度,延缓钢靶绝热剪切破坏的发生,提高复合结构的弹道极限;后聚脲涂层可与钢靶协调变形,形成冲塞质量块吸能,吸收弹体动能,在弹速较高时有较好的吸能能力。     

Thermal conductivity degradation induced by heavy ion irradiation at room temperature in ceramic materials

The thermal conductivity degradation induced by irradiation with energetic heavy ions at room temperature is studied and quantified. Three semi-metallic systems: titanium and zirconium carbides, titanium nitride, as well as a covalent compound: 6H silicon carbide were irradiated by 25.8 MeV krypton ions at 10¹⁶ and 6 . 10¹⁶ ions.cm^-2 doses to produce defects. During ion irradiation, inelastic collisions and elastic collisions occur at a different depth in a material. Two collision domains can be defined. Modulated thermoreflectance microscopy measurements were performed at differing frequencies to characterize the thermal conductivity degradation in these two domains for each of the investigated materials. Our results reveal a significant thermal conductivity degradation in the two collision domains for all materials. Elastic collisions are shown to degrade more strongly the thermal properties than inelastic ones. Scattering of thermal energy carriers is larger in elastic collision domain because displacement cascades produce a very high concentration of point defects: vacancies, interstitials and implanted Kr ions. The degradation coming from electronic interactions that seems to be more important in SiC can be explained by the presence of large populations of generated extended defects, facing to generated individual point defects in TiC, TiN or ZrC.     

Reactive plasma cladding of TiC/Fe cermet coating using asphalt as a carbonaceous precursor

A new process of preparing Ti-Fe-C composites powder for reactive plasma cladding, precursor carbonization-composition process, was developed. TiC/Fe cermet coatings were synthesized by reactive plasma cladding of the composite powder. XRD and SEM were employed to analyze the phase composition and microstructure of the composite powder and coating. The hardness and wear resistance of the coating was tested. Results show that: The compound powder prepared by precursor carbonization-composition process has very tight structure, which can avert the question of raw powder breaking-up in cladding process. The TiC/Fe cermet coating by reactive plasma cladding consists of alternate, laminated layers as following: the layers in which the round nanoscale TiC particles are dispersed within the α-Fe matrix and the layers of TiC accumulation. The TiC/Fe cermet coating by reactive plasma cladding shows superior hardness and wear resistance: The surface hardness of the TiC/Fe cermet coating is 68 ± 6 (HR30 N). In the same fretting conditions, the wear resistance of Ni60 coating is twelve times than that of the TiC/Fe cermet coating.     

Comparative study of titanium carbide and nitride coatings grown by cathodic vacuum arc technique

Titanium nitride (TiN), titanium carbide (TiC) thin films and TiC/TiN bilayers have been deposited on AISI 304 stainless steel substrates by plasma assisted physical vapor deposition technique—reactive pulsed vacuum arc method. The coatings were characterized in terms of crystalline structure, microstructure and chemical nature by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. Tribological behavior was investigated using ball on disc technique. The average coefficient of friction was measured, showing lower values for the TiN/TiC bilayer. Dynamic wear curves were performed for each coating, observing a better wear resistance for TiN/TiC bilayers, compared to TiN and TiC monolayers. On the other hand, the TiCN formation in the TiN/TiC bilayer was observed, being attributed to the interdiffusion between TiN and TiC at the interface. Moreover, the substrate temperature influence was analysing observing a good behavior at T_S = 115 °C.     

Microstructural analysis of TiC reinforced ferrous surface composites processed by accelerated electron beam irradiation

The present study aims to analyze microstructures of TiC reinforced ferrous surface composites processed by accelerated electron beam irradiation. Two kinds of powder/flux mixtures, i.e., TiC and (Ti + C) powders with 40 wt% of CaF₂ flux, were deposited evenly on an AISI 304 stainless steel substrate, which was then irradiated with electron beam. TiC agglomerates and pores were found in the surface composite specimen processed by irradiation of TiC powders because of insufficient melting of TiC powders. In the specimen processed by irradiation of Ti and C powders having lower melting points than TiC powders, a lot of large TiC carbides were precipitated in the melted region, together with a few TiC agglomerates or pores. This indicated the more effective TiC precipitation obtained from the melting of Ti and C powders, instead of TiC powders. The hardness of the surface composite layer was about two times higher than that of the AISI 304 substrate mainly due to the precipitation of TiC carbides.     

One-step synthesis of TiC/multilayer graphene composite by thermal plasma

Graphene hybrid materials have been attracting a great deal of attention due to their superior properties. Nevertheless, problems such as expensive and complicated production processes have limited their application to industrial fields. Here, we introduce a one-step synthesis of titanium carbide (TiC) nanoparticles on multilayer graphene nanosheet (TiC/multilayer graphene) composites using thermal plasma. Although there are three types of titanium alkoxides (titanium ethoxide, titanium isopropoxide and titanium n-butoxide), the TiC/multilayer graphene was synthesized from only titanium isopropoxide. The injection temperature of the precursor was varied to investigate the effects of the precursor concentration in the plasma region. A TiC/multilayer graphene hybrid material with crystalline TiC nanoparticles below 50 nm on graphene nanosheets was observed. The number of graphene nanosheet layers varied from one to over 10 according to the injection temperature. When titanium ethoxide and titanium butoxide were injected, TiC with amorphous carbon and graphite were synthesized. The formation of graphene is considered to be affected by the structure of the carbon chain in the precursors and the concentration in the plasma region.     

Comments on surface electronic properties of TiC and TiN

Some recent experimental and theoretical results on surface electronic properties of a special class of refractory transition metal compounds (TiC, TiN and ZrN) and particularly, on surface states, the surface charge self-consistency and the stability of the polar (111) surface, are discussed within a simple qualitative framework based on the use of energy weighted averages as the main tool of the analysis.     

The method of laser-sustained arc ignition

The method of laser-assisted vacuum arc deposition (laser-arc) was developed to effectively produce high-quality coatings, especially multilayer coatings with a reduced number of droplets. The efficiency of this method depends mainly on the ignition probability of the vacuum arc discharges. In the present work, the process of arc initiation by laser irradiation is studied and the influencing factors such as power density of laser irradiation, target material, and electrode configuration are discussed. It is shown that a high ignition probability (ρ>50%) on such coating materials at Ti, TiC, TiN, and C can be guaranteed with a laser power density of about 10⁸ W/cm², which can be achieved with a low-cost Nd-YAG pulse laser. Measurements of the plasma current preceding the arc ignition and microscopic investigations of the erosion pattern caused by the laser irradiation suggest that the process of plasma-sustained are ignition (unipolar arcing) plays an important role during the buildup phase of the vacuum arc discharge     

CLAM钢表面Fe-Al合金渗层的制备

FeAl/Al2O3阻氚涂层具有高阻氚因子、耐腐蚀和耐高温等优良性能,是ITER首选的阻氚涂层.Fe-Al合金渗层对Al2O3膜层的形成质量有重要的影响.本文采用了AlCl3-EMIC离子液体电镀法在CLAM钢表面镀铝,然后利用热处理使Al与基体相互扩散制备Fe-Al合金渗层.采用X射线衍射仪、扫描电子显微镜和能量散射谱仪研究了热处理时间和温度对渗层组织结构的影响.结果表明:渗层厚度随着热处理温度和时间的提升而增大,试样表面逐渐由富铝相向贫铝相转化.在不同热处理条件下获得的渗层与CLAM钢基体结合紧密,无孔洞等缺陷.热处理时间一定时,热处理温度对渗层生长速率的影响符合Arrhenius关系,拟合计算出CLAM钢的渗铝Arrhenius活化能为78.48 kJ/mol.在640℃和760℃时,渗层中金属间化合物的生长受晶界扩散速率与体扩散速率的共同影响.在综合考虑合理的渗层厚度、表面Fe-Al合金相、热处理成本的情况下,较优的热处理工艺为700℃/10 h.     

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Helium cooled ceramic breeder test blanket module (HCCB TBM) was introduced. The TBM system is mainly composed of test blanket, helium coolant system, tritium extraction system, coolant purification system, tritium measurement system and neutron activation system. The structural safety analysis of TBM mainly includes electromagnetic safety analysis, thermal-hydraulic safety analysis and neutronics safety analysis. The material safety analysis of TBM is divided into safety analysis of structural material, safety analysis of functional materials, such as tritium permeation barrier and tritium treatment materials. The research progress made by scholars at home and abroad in the above-mentioned security analysis research work was summarized, and the future safety analysis of the TBM tritium system was looked forward to, with a view to providing reference for the safety design of tritium systems.     

High performance nanostructured ZrO2 based thermal barrier coatings deposited by high efficiency supersonic plasma spraying

In this paper, the nanostructured zirconia (ZrO₂) based thermal barrier coatings (TBCs) deposited by high efficiency supersonic atmospheric plasma spraying (SAPS), were described. The phase composition, microstructure, thermal conductivity and thermal shock resistance of as-sprayed coating were studied. The results revealed that the as-sprayed coating was composed of tetragonal zirconia and consisted of some unmelted nanoparticles (30-50 nm) and nanograins (60-110 nm), and the latter was the main microstructure of the coating. The nanograins and homogeneously distributed micro-cracks of coating resulted in not only low thermal conductivity, but also high thermal cycling lives. Besides, the failure process of coating during thermal cycles was also investigated in the present work.