316L不锈钢基体上反应溅射添加YOx粘接层的Y2O3/Er2O3复合涂层的研究

为了研究添加粘接层对复合涂层的影响,采用脉冲反应溅射在316L不锈钢基体上制备了调制周期为700 nm左右(5层)的Y2O3/Er2O3复合涂层,通过调整氧氩比制备了不饱和氧化钇(YOx,x＜1.5)作为粘接层,研究了添加粘接层对复合涂层相组成、组织形貌以及涂层与基底结合情况的影响.X射线衍射(XRD)、扫描电子显微镜(SEM)、结合力及纳米硬度分析结果表明,当氧分压为0.036 Pa制备YO1.401粘接层时,Y2O3/Er2O3/YOx涂层的结合力相比于Y2O3/Er2O3复合涂层,涂层与基体的结合力增大了约60％,纳米硬度增大了近30％,绝缘电阻率测试结果表明,Y2O3/Er2O3/YOx涂层绝缘电阻率在1×109Ω·cm～1×1011Ω ·cm,绝缘性能良好.     

氧化铒涂层制备技术的研究进展

核聚变环境中材料的防氚渗透问题是聚变堆材料研究的重要课题之一.近年来,Er2O3涂层凭借着优良的热稳定性和防氚渗透性能引起了人们极大的关注.影响Er2O3涂层大规模应用在于其制备工艺及性能.综述了Er2O3涂层的制备技术及相关发展现状,展望了今后的发展趋势.     

硅酸钙及硅酸钠浓度对钛合金表面生物活性涂层的影响EI北大核心CSCD

使用微弧氧化技术,在恒压工作模式下,脉冲电压400 V,脉冲频率600 Hz,占空比15%,氧化时间10 min,电解液由CaSiO3,Na2SiO3·9H2O,EDTA-2Na和K2HPO4·3H2O组成,以不同浓度(0.0835-0.15 mol/L)的CaSiO3及不同浓度(0-0.06 mol/L)的Na2SiO3·9H2O,在3D打印基体钛片表面制备生物活性涂层。利用扫描电子显微镜、能谱仪、电化学工作站、涡流膜厚仪、Image-Pro Plus 6.0、轮廓仪、划痕仪等对涂层进行结构、性能及微观形貌表征,研究CaSiO3和Na2SiO3·9H2O浓度对涂层的影响。结果表明:随着CaSiO3浓度的增加,涂层厚度、粗糙度、微孔孔径及孔隙率、涂层钙磷元素比逐渐增大,耐腐蚀性能及膜基结合力变差;随着Na2SiO3·9H2O浓度的增加,涂层孔隙率及孔径先增大后减小,涂层厚度、粗糙度、涂层钙磷元素比逐渐增大,膜基结合效果和耐腐蚀性先变差后变好。当CaSiO3和Na2SiO3·9H2O的浓度分别为0.15 mol/L和0.015 mol/L时,涂层的性能最佳。     

EYTO粉末的光致发光特性

以柠檬酸为络合剂、钛酸丁酯为前驱体,制备了Er3 掺杂浓度(摩尔分数)为0.1%-5.0%的(Er,Y)2Ti2O7(EYTO)粉末.在700℃烧结EYTO粉末中EYTO相的晶化不完全,随着烧结温度的升高晶化程度显著提高,-OH基团的含量逐渐减少;在1000℃烧结,得到结晶完全且不含-OH基团的EYTO相.不完全晶化的EYTO相的PL谱为半高宽112 nm的单一宽峰,结晶完全的EYTO相其PL谱为发生Stark分裂的分立发光峰.随着烧结温度的升高EYTO粉末的PL强度和荧光寿命连续提高,归因于粉末中-OH基团的逐步脱除和EYTO相晶化程度的提高;Er3 浓度在0.1%-1.5%区间均呈现上升趋势,源于EYTO相为Er3 提供了均匀分散;Er3 浓度为1.5%时均达到最大值、荧光寿命为20.9 ms.当Er3 浓度超过1.5%时,Er3 -Er3 间的交互作用增强导致1.53μm的PL强度和荧光寿命持续下降.     

双层辉光离子渗金属技术制备Al-Y-Si氧化物涂层

本文采用双层辉光离子渗金属技术,在316L不锈钢表面进行Al-Y-Si共渗后氧化处理,制备致密的氧化物阻氚渗透涂层。通过XRD、SEM和EDS分析制备涂层的组织和结构,通过划痕试验、电化学测试和抗热震实验对其进行性能测试。结果表明,Y、Si元素的掺入能够生成连续致密的Al2O3涂层。用Y含量为10%的靶材制备的氧化涂层的组织和性能最佳,结合力为70.5N,涂层有很强的耐腐蚀性能,热震实验后表面无裂纹出现。     

不锈钢表面涂覆C-SiC涂层及其阻氢性能的研究

采用磁控溅射结合离子束混合技术在不锈钢基体上制备C-(50～90)％ SiC涂层,对涂层进行加热处理及氢离子注入.对各种条件下制备的涂层进行元素深度分布分析.结果表明,SiC组分含量高的涂层具有更好的阻氢性能,而C组分含量高的涂层与基体具有更好的结合性能,综合考虑今后在氚废物包装桶涂覆的实际使用工况来看,采用C-(75～85)％SiC作为涂层似乎更合适些.通过对涂层阻氢性能的分析发现,C-SiC涂层经加热处理后,涂层的阻氢能力得到进一步的提高,并且可以提高氢离子在涂层中的稳定性.     

液态锂铅与阻氚涂层材料相容性的研究进展

在聚变堆液态锂铅包层设计中，结构材料表面需覆盖一层阻氚涂层。涂层一般需要兼顾两方面功能：(1)高阻氢渗透因子，能够稳定地抑制氢渗透以维持反应堆的氚安全；(2)较高的耐腐蚀性能，以保证结构材料的结构完整性及热力学性能稳定性。阻氚涂层与锂铅直接接触会发生腐蚀，产生缺陷(如腐蚀坑等),影响涂层结构稳定性和阻氢渗透效率，进而直接影响涂层的服役寿命。本文重点综述了液态锂铅与阻氚涂层的相容性以及液态锂铅腐蚀对阻氚涂层阻氢性能影响的相关研究进展。已有的研究显示，Cr₂O₃-Er₂O₃-ZrO₂涂层、铝基涂层等在静止液态锂铅环境中均展现了良好的相容性和稳定的阻氢性能。本文还指出了目前相关研究存在的共性问题及未来可能的研究发展趋势。相关领域还需进行更为全面、系统的研究，为未来聚变增殖包层中阻氚涂层的服役寿命评估提供支撑。     

316L不锈钢表面激光熔覆Stellite6合金组织及其耐液态铅铋腐蚀性能

为提高316L不锈钢耐高温液态铅铋的腐蚀能力,通过使用同轴送粉的激光熔覆方式,在316L不锈钢表面制备一层Stellite6合金涂层,将其放入400℃的高温液态铅铋中进行500 h高速流腐蚀试验,其中相对流速设置为2.56 m/s.分析涂层的微观组织、物相组成、元素分布、显微硬度值等的变化规律,以及该涂层耐液态铅铋的腐蚀性能.涂层组织由等轴晶、树枝晶、胞状晶及平面晶组成,搭接区晶粒沿不同方向长大;涂层主要有γ-Co、CoCx、(Cr,Fe)7 C3及M23 C6等物相;各组分元素在涂层表面均匀分布,Co、Cr与Fe等元素在基体316L与涂层之间发生明显扩散;Stellite6涂层的硬度平均值为基体材料316L的2.3倍,且最高达到556.8HV.在进行高温液态铅铋高速流腐蚀后,316L不锈钢表面生成了大面积且连续的氧化物,存在大量微型腐蚀坑,Stellite6涂层表面仅存在少量氧化物,未发现明显的腐蚀坑,较好地维持了原貌;Stellite6涂层表面粗糙度值为1.0μm,而316L经腐蚀后的表面粗糙度为2.4μm.Stellite6合金涂层能够有效地提高316L不锈钢基体在高温液态铅铋合金中的耐腐蚀性能.     

电沉积液初始pH值对电沉积制备钽基RuO2·nH2O薄膜的影响

以RuCl3·2H2O水溶液为电沉积液,通过恒流电沉积法在钽箔上电沉积一层RuO2·nH2O薄膜;研究了电沉积液初始pH值对制备RuO2·nH2O薄膜的影响.分别采用SEM、EDS、XRD、粒度分析仪(DELSA 440SX analyzer control)对薄膜的形貌、薄膜元素、溶胶的Zeta电位及薄膜的物相进行观察与测试.结果表明,电沉积液初始pH值越高,RuO2·nH2O薄膜越疏松,龟裂纹越大,与基体结合力也越差.初始pH值为2.3时,薄膜的孔隙率最佳,综合性能指标最好.     

碱性镀液电沉积非晶-纳米晶Ni-Mo合金工艺探讨

用非晶态合金和纳米晶合金作电极材料各有利弊,而用酸性溶液制备的Ni-Co合金镀层存在内应力较大且电流效率低等不足.为此,采用电沉积技术在碱性镀液中制备了非晶-纳米晶Ni·Mo合金,利用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)、极化曲线等研究了电沉积工艺对镀层Mo含量、结构及形貌的影响.结果表明:镀层Mo含量随镀液中钼酸盐浓度增加而增加,随柠檬酸盐浓度增加、镀液温度升高、电流密度增大先增加后减小,pH值对镀层结构有显著影响;镀层Mo含量在21.00%～26.00%时,Ni-Mo合金镀层为非晶与纳米晶混合结构,非晶态相含量占60%以上,纳米晶的晶粒尺寸较小,镀层表面均匀、颗粒细小、致密性较高;10.0 g/LNa2MoO4·2H2O,64.0 g/L Na3C6H5O7·H2O,pH值10.0,电流密度5～8 A/dm2,温度35℃时,获得的镀层为非晶与纳米晶混合结构,且表面质量较好.     

Magnetic coupling in La0.67Ca0.33MnO3/La0.67Sr0.33CoO3/La0.67Ca0.33MnO3 sandwiches

La_0.67Ca_0.33MnO₃ (LCMO)/La_0.67Sr_0.33CoO₃ (LSCO)/LCMO trilayer films are fabricated on single-crystal substrates NdGaO₃ (110) and the interlayer coupling are investigated. Compared with LCMO single layer, sandwiches showed the enhanced metal-insulator transition temperature of LCMO layers. The magnetoresistance is dependent on spacer thickness and the peak value dramatically decreases when LSCO layer is thick enough because of shorting by the LSCO layer. The magnetic coercivity H_C shows a nonmonotonic behavior with changing spacer layer thickness and the waist-like hysteresis indicates that there is an indirect exchange coupling between the top and bottom LCMO layers across the spacer layer.     

Varistor properties of ZnO-Pr6O11-CoO-Cr2O3-Y2O3-In2O3 ceramics

The varistor properties of the ZnO-Pr₆O₁₁-CoO-Cr₂O₃-Y₂O₃-In₂O₃ ceramics were investigated for different concentrations of In₂O₃. The increase of In₂O₃ concentration slightly increased the sintered density (5.60-5.63 g/cm³) and slightly decreased the average grain size (3.4-2.9 μm). The breakdown field increased from 6023 to 14822 V/cm with increasing concentration of In₂O₃. The nonlinear coefficient increased from 17.6 to 44.6 for up to 0.005 mol%, whereas the further doping caused it to decrease to 36.8. In₂O₃ acted as an acceptor due to the donor concentration, which decreases in the range of 1.02 × 10¹⁷ to 0.24 × 10¹⁷/cm³ with increasing concentration of In₂O₃.     

Nanocrystallization of SrBi2Nb2O9 from glasses in the system Li2B4O7---SrO---Bi2O3---Nb2O5

Transparent glasses in the system (100−x)Li₂B₄O₇–x(SrO---Bi₂O₃---Nb₂O₅) (10≤x≤60) (in molar ratio) were fabricated by a conventional melt-quenching technique. Amorphous and glassy characteristics of the as-quenched samples were established via X-ray powder diffraction (XRD) and differential thermal analyses (DTA) respectively. Glass–ceramics embedded with strontium bismuth niobate, SrBi₂Nb₂O₉ (SBN) nanocrystals were produced by heat-treating the as-quenched glasses at temperatures higher than 500 °C. Perovskite SBN phase formation through an intermediate fluorite phase in the glass matrix was confirmed by XRD and transmission electron microscopy (TEM). Infrared and Raman spectroscopic studies corroborate the observation of fluorite phase formation. The dielectric constant (_r) and the loss factor (D) for the lithium borate, Li₂B₄O₇ (LBO) glass comprising randomly oriented SBN nanocrystals were determined and compared with those predicted based on the various dielectric mixture rule formalism. The dielectric constant was found to increase with increasing SBN content in LBO glass matrix.     

Syntheses of hollandite type Rb2Cr8O16, K2Cr2V6O16 and K2V8O16

Hollandite-type compounds, Rb₂Cr₈O₁₆, K₂Cr₂V₆O₁₆ and K₂V₈O₁₆, were synthesized under high P-T conditions up to 1200°C and 7GPa. The structural refinement using a single crystal of Rb₂Cr₈O₁₆ confirms that the structure is similar to that of K₂Cr₈O₁₆. Magnetic measurements indicate that Rb₂Cr₈O₁₆ is ferromagnetic below 295K, K₂Cr₂V₆O₁₆ paramagnetic down to 77K and K₂V₈O₁₆ has susceptibility anomaly at 175K. These compounds are all semiconductive and show discontinuities in temperature-resistivity curves at points corresponding to magnetic anomalies.     

PbSbBiS4-Sb2S3 and PbSbBiS4-Bi2S3 joins in the PbS-Sb2S3-Bi2S3 system

Phase equilibria along the PbSbBiS₄-Sb₂S₃ and PbSbBiS₄-Bi₂S₃ joins of the PbS-Sb₂S₃-Bi₂S₃ system have been studied for the first time using differential thermal analysis, X-ray diffraction, microstructural analysis, microhardness tests, and density measurements, and the phase diagrams of the joins have been mapped out. The joins are shown to be pseudobinary with limited series of terminal solid solutions. The solid solutions are p-type semiconductors.     

Microstructures of YBa2Cu3O7/La0.7Ca0.3MnO3 and La0.7Ca0.3MnO3/YBa2Cu3O7 bi-layers grown on (001)LaAlO3

Epitaxial YBa₂Cu₃O₇/La_0.7Ca_0.3MnO₃ (YBCO/LCMO) bi-layers and La_0.7Ca_0.3MnO₃/YBa₂Cu₃O₇ (LCMO/YBCO) bi-layers were grown on (001)LaAlO₃ by pulsed laser deposition, and their microstructures were compared by transmission electron microscopy investigation. In the YBCO(100 nm)/LCMO(150 nm) bi-layers, the LCMO layer consists of columnar grains of ~ 17 nm in diameter and contains mixed orientation domains of [100]_c, [010]_c and [001]_c. The YBCO layer is totally c-axis oriented and the YBCO lattices are tilted − 2.5° to + 2.5° as they grew on the rough surfaces of LCMO columnar grains. For the LCMO(140 nm)/YBCO(140 nm) bi-layers, the LCMO/YBCO interface is sharp and flat. The initial 12-nm thickness of the YBCO layer is composed of c-axis oriented domains, and the upper part of YBCO layer is [100] oriented. The LCMO layer was predominantly [001]_c oriented while [100]_c-oriented domains were occasionally observed.     

Vapour-liquid equilibria in the ternary mixtures N2---CH4---C2H6 and N2---C2H6---C3H8

A systematic study was performed with mixtures consisting of N₂, CH₄, C₂H₆ and C₃H₈, to investigate experimentally phase equilibria and caloric properties and to test the accuracy of thermodynamic correlations. The first part of this Paper reports results of T---p---x---y measurements on ternary systems in the range 20 < p < 120 bar and 140 < T < 220 K. The results are compared with data calculated by generalized equations of state.     

Characterization of YBa2Cu3O7/PrBa2Cu3O7 superlattices

We investigated the structural and superconducting properties ofc-axis oriented (YBa₂Cu₃O₇) _nY /(PrBa₂Cu₃O₇) _npr superlattices with thicknesses of the individual layers down to one unit cell (10nY1; 18>nPr 1). By transmission electron microscopy and X-ray diffraction we find an excellent structural quality of the samples, though the quantitative analysis shows the existence of defects. In superlattices with decoupled YBa₂Cu₃O₇ layers of two unit cell thickness we find a highT _c value of 75 K. We probed the flux line structure in the superlattices by measurements of the critical current density in magnetic fields. The experiments show that the flux-line dynamics is dominated by the movement of pancake vortices.     

Structural study of Sr0.3Ba0.7Nb2O6 and La0.030Sr0.255Ba0.700Nb2O6 ceramic systems

Sr_0.3Ba_0.7Nb₂O₆ (SBN) and La_0.030Sr_0.255Ba_0.700Nb₂O₆ (LSBN) ceramic compounds have been prepared using the traditional ceramic method at two different calcination temperatures (900 and 1000 °C) and later sintered both at 1400 °C. A study of the effects of the calcination temperatures and La substitution on the morphological, compositional, and structural properties of SBN and LSBN is presented using scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. From Rietveld refinement processes, the XRD patterns were interpreted to evaluate such effects in the structural parameters and the site occupation factors of the heavy metals and oxygen atoms. The effect of the incorporation of La resulted in a 0.25% cell contraction and turned out to be higher than the 0.08% dilation effect produced by the increase of calcination temperature. The La ion with similar effective ionic radius and higher electronegativity is incorporated into the structure occupying the A₁ site just like the Sr ions in the SBN compound. Differences in the site occupation factors between the SBN and LSBN samples lead to substantial changes in the physical properties such as temperature of relative dielectric constant maximum, relative dielectric constant, and dielectric loss, correlated with the distortion and the relative orientation of the oxygen octahedra.     

The effect of Bi1.5Zn0.5Nb0.5Ti1.5O7 cover layer on the dielectric and tunable properties of Ba0.6Sr0.4TiO3/Bi1.5Zn0.5Nb0.5Ti1.5O7 bilayered thin films

Bi_1.5Zn_0.5Nb_0.5Ti_1.5O₇ (BZNT) thin films with different thicknesses as cover layers were deposited on the Ba_0.6Sr_0.4TiO₃ (BST) thin films on the Pt/Ti/SiO₂/Si substrates by radio frequency magnetron sputtering method. The microstructure, surface morphology, dielectric and tunable properties of BST/BZNT heterogeneous bilayered films were investigated as a function of the thickness of BZNT films and the effect of BZNT films on the asymmetric electrical properties of BST/BZNT bilayered films was discussed. It was found that BZNT cover layer significantly improved the leakage current and the dielectric loss, and the dielectric constant and tunability of BST/BZNT bilayered thin films simultaneously decreased with the increasing thickness of BZNT films. The BST/BZNT bilayered thin film with a 50 nm BZNT cover layer gave the largest figure of merit (FOM) of 33.48 with the upper tunability of 55.38%. The asymmetric electrical behavior of BST/BZNT bilayered films is probably related to an internal electric field caused by built-in voltages at Pt/BST and BZNT/Au interfaces.