C掺杂对Al中He行为的影响

用离子注入技术实现了Al表面C元素的掺杂,并利用XPS,XRD,TEM和SEM研究了C掺杂对Al中离子注入He行为的影响.结果表明,掺杂的C在Al表面形成了Al_4C_3,随着C掺杂量的增加,Al表面组织的择优取向和晶胞体积发生改变,从而影响了Al中的He离子注入行为.预先掺杂的C对He离子注入Al表面的鼓泡行为有重要影响,其影响程度与掺杂剂量有关.小剂量C掺杂后,能有效抑制鼓泡的长大,并使Al表面鼓泡均匀分布;更高剂量C掺杂后,C对表面鼓泡的抑制作用减弱,甚至加剧He离子的辐照损伤,Al表面出现孔洞和剥落现象.掺杂的C对Al基体的微观结构也有很大影响.     

XRD研究Fe、C掺杂对He离子注入Al表面晶格畸变的影响

用离子注入技术实现了Al表面Fe、C元素的掺杂,并用XRD研究Fe、C掺杂对He离子注入Al表面晶格畸变的影响。结果发现,预先掺杂的Fe、C在Al表面的晶格畸变中扮演重要角色,且影响程度与掺杂剂量有关。随着预先掺杂Fe剂量的增大,Al表面晶格畸变量先减小后增加,表明小剂量的Fe掺杂有助于降低He离子注入引起的晶格畸变。C掺杂后能进一步降低预先掺杂Fe引起的晶格畸变,降低程度随C剂量的增加而增加。可见,小剂量的Fe和高剂量的C共掺杂能有效降低He离子注入后Al表面的晶格畸变。     

Ti掺杂对ZrCo贮氚合金中氦行为的影响研究

采用掠入射X射线衍射（GIXRD）、弹性离子反冲（ERD）、氦热解吸（TDS）、扫描电镜（SEM）对直流磁控溅射法制备的含氦Zr-Co、Zr-Ti-Co薄膜进行分析，分别得到样品物相、氦的深度和浓度分布、氦热解吸图谱以及热解吸前后的表面形貌。氦热解吸实验曲线反映出Ti的掺杂有利于抑制ZrCo贮氚合金中氦的迁移、聚集和发展，提升相应捕陷位置中氦的释放温度；氦热解吸后，Zr0.8Ti0.2Co薄膜样品的晶界密度相比ZrCo薄膜样品更低，降低减少了氦泡迁移的通道，延缓高温下氦泡迁移合并的趋势，表明掺杂Ti可提升ZrCo合金的固氦能力,对高温条件下氦的释放具有抑制作用。     

铝合金等离子体基离子注入氮／钛层的结构

用X射线光电子能谱（XPS）和小掠射角X射线衍射（GXRD）研究了铝合LY12等离子体基离子注入氮／钛改性层的结构。结果表明。氮在注入层呈高斯分布,而钛沿注入方向逐渐减少。钛的注入对已注入的氮的分布有重要影响。钛的等离子体密度直接影响钛在改性层中的成分、相结构。改性层主要由TiO2,Al2O3,Aln,TiAl3,TiN或Ti组成。     

稀土Y对ASISI430不锈钢抗高温氧化性能影响的研究

本工作通过离子注入的方式,在AISI430合金表面注入不同剂量的稀土Y进行改性,研究了不同剂量的稀土Y对合金高温抗氧化性的影响。采用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、光电子能谱仪（XPS）分析氧化膜的物相构成、微观组织形貌、稀土Y的化学形态,并通过VL200DX超高温激光共聚焦显微镜对氧化过程进行原位观察。结果表明：合金表面注入稀土Y剂量为6×1017ions/cm2具有最佳抗氧化性和抗剥落性,相比原始试样,单位面积增重量以及剥落量分别减少了43.7%, 78.4%。合金表面注入Y优先氧化为Y2O3,一方面促进氧化膜的形成,另一方面抑制了晶粒长大。此外,晶界处Y2O3阻碍了金属阳离子通过晶界向外扩散。重要地,部分Y取代了MnCr2O4尖晶石中Mn2+、Cr3+占位,产生空穴缺陷,缓解了氧化层内应力,减少裂纹和孔洞的产生,使氧化层与基体结合紧密。     

氦离子预注入对钨中氘滞留行为的影响

利用高能离子注入机和直线等离子体模拟装置,本文研究了高能氦离子预注入对氘等离子体辐照后钨中氘滞留行为的影响。采用FIB-SEM、TEM、GD-OES和TDS等分析方法,分析了氦离子预注入对钨中氘滞留行为的影响。结果表明：氦离子预注入在辐照损伤区域形成大量氦泡,钨经过氘等离子体辐照后,表面的氘泡数量明显低于未经过氦离子预注入的样品。GD-OES分析中可以看到在氦捕获位处氘滞留浓度明显升高,同时氦离子预注入增加了氘在钨中的扩散深度,结合TDS分析可知氦离子预注入增加了氘在钨中的滞留总量,这是由于氦离子预注入后,形成的缺陷又为钨中氘的俘获提供大量新的位点,从而导致钨中的氘滞留量明显提高。     

氮离子注入TiNi形状记忆合金表面改性

采用1×1016ions/cm2的注入剂量对TiNi形状记忆合金进行氮离子注入,注入加速电压为50 keV。采用X射线衍射和X射线光电子能谱对氮离子注入前后TiNi形状记忆合金表面的物相以及化学成分进行了分析。结果表明,氮离子注入前后TiNi合金表面都被氧化。氮离子注入前TiNi形状记忆合金表面存在少量TiO2、Ti3O5和Ti2O3。氮离子注入后的TiNi形状记忆合金表面有TiN新相生成,且在氮离子注入后的TiNi形状记忆合金表面还存在少量TiO2、Ti3O5。     

钴离子注入对Fe基非晶合金摩擦磨损行为的影响

利用金属气相真空电弧(MEVVA)法对由电弧熔炼、喷铸法制备的大块Fe基非晶Fe41Co7Cr15Mo14C15B6Y2进行Co离子注入,注入剂量为3×1017ion/cm2.利用纳米压入法表征了离子注入对铁基非晶力学性能的影响,采用SRV球-盘式高温摩擦磨损试验机进行干摩擦磨损试验,分析了离子注入和晶化处理对Fe基大块非晶摩擦磨损性能的影响.利用形貌仪测定磨痕横截面形貌,SEM观察磨损表面形貌,EDS进行成分分析.结果表明,对非晶进行离子注入后,硬度从15 GPa提高到了21 GPa,弹性模量从230GPa提高到了290 GPa;离子注入和晶化处理后抗磨损性能得到了很大的提高;铁基非晶磨损机理以脆性剥落为主,同时伴随着氧化磨损;而经离子注入后,脆性剥落块明显减小,晶化后的磨损机理主要是硬质相从非晶基体中剥离.     

Al离子高温注入Fe靶的表面合金化研究

利用能量120 keV的Al离子注入250和500℃的Rj靶,研究了高温注入条件下Fe靶表层合金化过程.Fe靶表 层A1的浓度一深度分布和相结构分别采用Rutherford背散射谱(RBS)和X射线衍射谱(XRD)分析.实验结果表明:注 入剂量为1×10"cm一。时, AI离子注入250和500℃Fe靶的注入深度分别为180和200 nrn,峰值浓度均为10％(原子 分数).离子注入层中形成了金属间化合物AllaFe4相,同时记录到少量残留氧造成的氧化物A1Ee03相.利用有效形成热模型 合理解释了Al离子高温注入Fe靶的合金相形成规律,利用相应金属离子高温注入金属靶传质模型可获得与实验相符的结果.     

Ni离子注入纯铜的表面改性

采用MEVVA源离子注入设备进行了纯铜表面镍离子注入的改性实验研究,采用透射电镜和X射线衍射仪对改性层显微组织进行分析表征.结果表明随着Ni离子注入剂量的增加,铜表面改性层发生一系列强化过程.纳米硬度和摩擦磨损实验结果表明当注入剂量达到7.5×1017ion/cm2时,注入层的硬度值可达基体的2倍,滑动摩擦因数仅为基体的47%.高剂量的离子注入是对纯铜进行表面改性的一种有效的方法.     

Influence of iron doping on morphological,structural and optical properties of zinc oxide thin films prepared by dip-coating method

Undoped zinc oxide and iron-doped zinc oxide thin films have been deposited by the sol-geldipcoating method. The Fe/Zn nominal volume ratio was 5% in the solution. The effects of Fe incorporation on morphological, structural, and optical properties of ZnO films were investigated. The scanning electron microscopy measurements showed that the surface morphology of the prepared thin films was affected by Fe doping. The X-ray diffraction patterns of the thin films showed that doped incorporation leads to substantial changes in the structural characteristics of ZnO thin films. The optical absorption measurements indicated a band gap in the range of 3.31 to 3.19 eV. The X-ray photoelectron spectroscopy demonstrated that Fe is incorporated in the ZnO matrix with 6.5 atomic percent (at %). The energy dispersive spectroscopy studies indicated the formation of ZnO with high efficiency.     

Synthesis and Microstructure Evolution of Nano-Titania Doped Silicon Coatings

The Anatase phase of Titania (TiO₂) in nanocrystalline form is a well known photocatalyst. Photocatalysts are commercially used to accelerate photoreactions and increase photovoltaic efficiency such as in solar cells. This study investigates the in-flight synthesis of Titania and its doping into a Silicon matrix resulting in a catalyst-dispersed coating. A liquid precursor of Titanium Isopropoxide and ethanol was coaxially fed into the plasma gun to form Titania nanoparticles, while Silicon powder was externally injected downstream. Coatings of 75-150 μm thick were deposited onto flat coupons. Further, Silicon powder was alloyed with aluminum to promote crystallization and reduce the amorphous phase in the Silicon matrix. Dense coatings containing nano-Titania particles were observed under electron microscope. X-ray diffraction showed that both the Rutile and Anatase phases of the Titania exist. The influence of process parameters and aluminum alloying on the microstructure evolution of the doped coatings is analyzed and presented.     

Salt Spray Corrosion Resistance of Aluminized Coatings on X70 Pipeline Steel by Laser Thermal Radiation

利用激光热辐射对X70管线钢表面进行渗铝处理,通过SEM观察了渗铝层表面和界面形貌,并对其结合界面的化学元素进行了EDS线能谱分析。对盐雾腐蚀后界面化学元素进行了EDS面能谱分析,用XRD分析了盐雾腐蚀前后渗铝层表面的物相,研究了渗铝层对X70管线钢抗盐雾腐蚀性能的影响。结果表明,激光热辐射渗铝处理后X70管线钢表层为氧化铝层,化学元素在表面和界面分布均匀,无富集现象,在结合界面处相互渗透,形成冶金结合形式;盐雾腐蚀后原始试样表面点蚀严重,形成全面腐蚀;渗铝处理后试样表面生成致密的Al2O3保护膜,阻止了腐蚀性介质Cl-离子和基体活性Fe的接触,提高了X70管线钢抗盐雾腐蚀能力。     

铬铁原矿粉掺杂制备CrFeNiSiAl0.5高熵合金涂层及其组织性能

目的 以40Cr钢为基体,制备掺杂铬铁原矿粉的CrFeNiSiAl0.5高熵合金涂层,提高其硬度与耐磨性.方法 在Cr、Fe、Ni、Al、Si纯金属粉末中掺杂铬铁原矿粉,矿粉有效原子数分数为0％、5％、10％、15％时,采用激光熔覆技术,在40Cr钢基体上制备CrFeNiSiAl0.5高熵合金涂层.利用X射线衍射仪、金相显微镜、扫描电子显微镜,表征高熵合金涂层的物相结构及微观组织.利用硬度计、磨粒磨损机,对涂层的硬度及耐磨性能进行表征.结果 不含铬铁原矿粉时,高熵合金涂层为单一的BCC相,铬铁原矿粉为10％时,出现FCC相.高熵合金涂层微观组织以胞状树枝晶为主,涂层与结合区存在明显分界,与基体呈良好的冶金结合.不含铬铁原矿粉时,高熵合金涂层平均硬度值为643.5HV;铬铁原矿粉为15％时,涂层平均硬度值为838.1HV,是基体的3.4倍.磨损率随铬铁原矿粉占比的增加而降低,铬铁原矿粉有效原子数分数为15％时,磨损率约为0.14 mg/mm2,耐磨性能最好.结论 在40Cr钢基体上成功制备出了以铬铁原矿粉为掺杂组元的高熵合金涂层,铬铁原矿粉的掺入,提升了CrFeNiSiAl0.5高熵合金涂层的硬度与耐磨性.     

Ti和Fe添加剂对氢化锂铝放氢性能的影响

通过PCT设备和XRD对掺杂Ti和Fe的LiAlH4试样进行了研究.结果表明:掺杂Ti和Fe都明显地降低了LiAlH4的放氢温度、放氢量和放氢速率,其中掺杂5mol?试样的放氢温度降低最低,并且放氢量明显地高于掺杂Ti试样的放氢量;和掺杂5 mol% Ti的试样相比,掺杂5 mol?的试样在第一分解阶段的分解速率明显低于前者;对于经过250 ℃热分解后的掺杂5 mol% Fe和1、3、5 mol%Ti的试样的XRD分析结果显示,掺杂催化剂并没有引起晶体结构的变化,也没有发现Ti和Fe相或含Ti和Fe的第二相的存在     

He and Cr effects on radiation damage formation in ion-irradiated pure iron and Fe–5.40 wt.% Cr: A transmission electron microscopy study

The first walls of future fusion reactors will be exposed to 14 MeV neutron irradiation. In order to gain insight into their radiation resistance, model materials (a high purity iron and a Fe–5.40 wt.% Cr alloy) have been ion-irradiated in the JANNuS facility to high doses with and without helium. The materials were self-ion-irradiated at 500 °C up to ～100 displacements per atom (dpa) with gas implantation rates equal to 0, 2.5 and 25 appm He dpa^?1. He and Cr effects on the radiation damage formation have been studied at the microscopic scale by transmission electron microscopy. In pure Fe, a coarse dislocation network was observed after irradiation, irrespective of helium implantation rate. Concerning the V-containing features (nanobubbles or cavities), few large cavities were observed in pure iron irradiated without helium. The main effect of helium implantation was to increase their density and diminish their size. The main effect of chromium was to reduce the swelling for all the He implantation rates. Furthermore, in both materials, the cavity formation was mainly heterogeneous.     

激光增材制造WC增强铁基复合材料组织结构及性能研究

目的采用激光增材制造技术制备WC增强铁基复合材料,并对其显微组织结构及性能进行表征测试,为后续制备大体积激光增材做技术理论及工艺储备。方法加入质量分数为10%的WC粉末,利用激光增材制造技术在40Cr钢表面制备WC增强铁基复合材料层,采用X射线衍射仪(XRD)、金相显微镜(OM)、扫描电子显微镜(SEM)、硬度计、磨粒磨损机、电化学工作站等,分析激光增材层逐层组织结构、力学性能及其变化规律。结果激光增材层与基体呈良好冶金结合,相组成为α-(Fe,Cr)、Fe2C、Fe2W、Fe3B。表层、亚表层及中层区显微组织为鱼骨状树枝晶,在其周围存在硬质颗粒,随着表面距离的增加,底层区出现胞状晶。亚表层区晶粒最为细小均匀,硬度最高,为1057HV,是基体的4.2倍。中层区磨损率最低(0.29 mg/mm^2),耐磨性最好,自腐蚀电位最高(-205.86 mV),耐蚀性能最好。底层区钝化电流密度最小,为0.1865μA/cm^2,腐蚀速度最慢。结论加入的WC颗粒与铁基粉反应生成的Fe2C与Fe2W形成第二相强化,提高了基体的硬度、耐磨性及耐蚀性,且增材层亚表层区硬度最高,中层区耐磨性、耐蚀性最好。     

Optimization of dielectric constant temperature coefficient of pyrochlores containing bismuth

1　INTRODUCTIONDielectric ceramics are widely used with ad vances in microelectronic technologies. Bismuth based pyrochlores exhibit well known high fre quency dielectric properties for multilayer capaci tor. Group of pyrochlore structured compounds isof general formula A2B2O7(where A is trivalent orbivalent cations and B is quadrivalent and quinque valent cations). As a member of the pyrochlorefamily of compound, bismuth zinc niobate is a typi cal high frequenc…     

Vapor growth of SiC bulk crystals and its challenge of doping

The paper reviews the so-called Modified-PVT (M-PVT) technique which combines the state of the art PVT technique for SiC crystal growth with physical and chemical vapor deposition (PVD and CVD) for fine tuning of growth parameters and improved doping. Using this technique, currently the highest aluminum doping levels and lowest resistivity values in p-type bulk SiC were achieved that for the first time meet device fabrication needs. The paper will address fundamentals of the Modified-PVT technique including a comparison of experimental results with numerical modeling of the gas flow. As additional gas feeding helium, helium-aluminum vapor for p-type doping, phosphine for n-type doping and propane for fine tuning of the C/Si gas phase composition will be discussed. So far, the M-PVT concept, i.e. mixture of conventional PVT and fine tuning by PVD/CVD, enables the most flexible doping of SiC single crystals.