超细晶/纳米晶钨——未来聚变堆面向等离子体材料

钨为未来高参数准稳态运行聚变堆最有前景的面向等离子体材料。超细晶/纳米晶结构有可能提高钨材料的热力学性能和抗粒子辐照性能,因而成为一个很有前途的研发方向。深度塑性变形和粉末冶金均已在制备超细晶/纳米晶钨方面开始了初步探索,深度塑性变形的等通道角挤压法因能制备致密度高、韧脆性能优异、大尺度的块体超细晶/纳米晶钨,极有可能在钨基面向等离子体材料制备方面取得突破。     

纳米和超细晶金属材料的退火强化

本文综述了纳米和超细晶金属材料的退火强化研究现状和发展趋势。本文关注致密纳米和超细晶材料的研究,首先介绍了电沉积纳米Ni、强塑性变形制得的超细晶金属钛和纯铝的退火强化的实验现象,随后综述了这一强化现象的微观机理,最后探讨了进一步的实验及理论分析的途径。     

铝诱导晶化法低温制备多晶硅薄膜

为了满足在普通玻璃衬底上制备多晶硅薄膜晶体管有源矩阵液晶显示器,低温（＜６００℃）制备高质量多晶硅薄膜已成为研究热点．本文研究了一种低温制备多晶硅薄膜的新工艺：金属诱导非晶硅薄膜低温晶化法．在非晶硅薄膜上蒸镀金属铝薄膜,并光刻形成铝膜图形,而后于氮气保护中退火．利用光学显微镜和拉曼光谱等测试方法,研究了Ａｌ诱导下非晶硅薄膜的晶化过程,结果表明;在５６０℃退火６ｈ后;铝膜下的非晶硅已完全晶化,确定了所制备的是多晶硅薄膜．初步探讨了非晶硅薄膜金属诱导横向晶化机理．     

纳米超细晶材料的制备方法

主要介绍了纳米超细晶材料的制备方法、应用状况以及研究发展趋势.认为除深度塑性加工方法外,传统的各种制备方法存在着不能获得大尺寸块体,材料内部有微孔隙存在,工艺过程复杂等不足.深度塑性变形解决了传统纳米超细晶材料制备方法存在的问题.纳米超细晶材料的应用并不是很广泛,因此在以后的研究中从研究到应用还需做大量工作.     

超细晶/纳米晶钛合金的研究与进展

原位生成超细晶/纳米晶钛合金是以钛基纳米材料为机体、微米级树枝晶为韧性增强相的合金，它不仅比一般的纳米金属具有更好的强度和韧性的匹配，而且比传统的铸造钛合金具有更优异的铸造性能，是有着广阔应用前景的新型合金。介绍了原位生成钛基纳米晶/超细晶亚共晶合金的发展、原理与研究现状。     

磁控溅射技术制备硅纳米晶多层膜及微观结构表征

在室温下,分别利用常规磁控溅射和反应磁控溅射技术交替沉积Si薄膜和Si1-xNx薄膜在单晶硅基体上制备了Si/Si1-xNx纳米多层膜。接下来,在高温下对Si/Si1-xNx多层膜进行退火诱发各层中形成硅纳米晶。研究了Si1-xNx层厚度和N2流量沉积对Si/Si1-xNx多层膜中Si量子点形成的影响。TEM检测结果表明,N2流量为2.5mL/min时沉积的多层膜退火后形成了尺寸为20～30nm的等轴Si3N4纳米晶;N2流量为5.0mL/min时沉积的多层膜退火后在Si层和Si1-xNx多层中均形成了硅纳米晶,而在7.5mL/min N2流量下沉积的Si/Si1-xNx多层膜退火后仅在Si层中形成了硅纳米晶。     

纳米晶ZnS薄膜的制备方法及应用进展

纳米晶ZnS薄膜具有带隙宽度大、光学透过率高、介电常数低、化学稳定性好等特点,在透明导电膜、铜铟镓硒(CIGS)薄膜太阳能电池、发光器件、功能玻璃等领域表现出巨大的应用潜力。综述了纳米晶ZnS薄膜常用的制备方法,如磁控溅射法、化学浴沉积法、真空蒸发法和化学气相沉积法,同时还介绍了纳米晶ZnS薄膜的掺杂改性研究及其在相关领域的应用进展。     

纳米晶PCT薄膜的合成与表征

纳米材料的制备技术结合Ｓｏｌ－Ｇｅｌ工艺在（１００）单晶硅上制备了粒径在２０￣８０ｎｍ的多晶ＰＬＴ（Ｐｂ１－ｘＬａｘＴｉＯ３）纳米晶膜，并用ＩＲ、ＴＧＡ、ＸＲＤ、ＳＥＭ等对膜的制备过程及结果进行了研究。结果表明，所制备的ＰＬＴ纳米晶膜属多晶钙钛矿结构，薄膜表面平整致密，厚度均匀，约为１ｕ，颗粒为球形或椭球形，粒度呈对称分布。     

直接氮化法制备纳米晶TiN薄膜

首先采用溶胶-凝胶法在Al2O3基体上制备了TiO2纳米晶薄膜，然后在管式气氛炉中，用氨气作为还原剂，直接氮化制备TiO2纳米晶薄膜；从而成功地的α-Al2O3陶瓷基片上制备了纳米晶TiN薄膜。利用XRD、XPS、FE-SEM等分析技术，研究了制备的纳米晶TiN薄膜的相组成及形貌。结果表明最佳工艺条件为：氮化温度为700℃，氮化时间为1h。     

铝诱导非晶硅薄膜低温晶化及结构研究

介绍了一种非晶硅薄膜低温晶化的新工艺－金属诱导非晶硅薄膜低温晶化。在非晶硅膜上蒸镀金属铝薄膜,而后于氮气保护中退火,实现了非晶硅薄膜的低温（＜600℃）晶化。利用X射线衍射、光学显微镜及透射电等测试方法,研究了不同退火工艺对非晶硅薄膜低温晶化的影响,确定了所制备的是多晶硅薄膜。     

Characterization of (Al, Si)N films deposited by balanced magnetron sputtering

Hard and transparent nanocomposite (Al, Si)N films are attractive for optical applications. In this paper, experimental results will be reported on nanocomposite (Al, Si)N films prepared by balanced magnetron sputtering. Microstructure and properties of the films were systematically characterized as a function of Si content of the films. It is shown that the (Al, Si)N films are transparent and exhibit no absorption in a wide range of wavelengths from ~ 0.3 to ~ 9 µm, i.e. from ultraviolet to mid-infrared region. Maximum hardness exceeding 25 GPa has been obtained when the Si content of the films is above 25 at.% and the microstructure of the films undergoes a transformation from nanocrystalline to amorphous states. It is demonstrated that the microstructure detail of the films is different, as compared with that of the films prepared by using unbalanced magnetron sputtering, and the reasons for this discrepancy is discussed.     

磁控共溅射Ni3 Al合金薄膜的微观结构及电阻特性

研究了室温下采用直流磁控共溅射法在抛光玻璃和Si基底上沉积Ni3Al合金薄膜的制备工艺、微观结构和电阻特性.采用SEM、EDX、AFM、TEM等测试分析了不同基底、溅射功率、工作气压等因素对薄膜微观结构、成分比和电阻特性的影响.结果表明:采用大功率混合溅射可以得到多晶态Ni3Al纳米合金薄膜,且呈多层岛状生长.所得薄膜具有良好的导电性,与玻璃相比,在Si基底上的薄膜表面光滑平整,晶粒更小,电阻率略大.然而随着厚度的减小,薄膜的电阻率增加迅速,发生金属向绝缘体过渡的相变,而厚度较大时这种现象不明显,这表明Ni3Al薄膜相变与厚度及晶格中氧含量有关.     

纳米高频软磁薄膜材料研究进展

由于高频软磁薄膜材料具有巨大的应用前景因此获得了人们广泛的关注。对纳米合金软磁薄膜、纳米软磁颗粒膜、多层膜以及图形化薄膜进行了分类综述,分别介绍了各类薄膜的制备方法、化学成分、微观结构特点和高频物理性能,并对影响其性能的主要因素进行了讨论。由于纳米高频软磁薄膜材料相对于传统磁性材料具有显著优势,所以纳米合金软磁薄膜有望取代铁氧体作为制作高频磁性器件的主要应用材料。由于纳米软磁颗粒膜、多层膜以及新兴的图形化薄膜具有材料结构设计和物性剪裁的自由度,因此将是今后的重点研究方向。     

Al2O3基陶瓷及玻璃基底制备Ta-N薄膜微结构与电学特性的比较研究

在N2、Ar气氛中,采用反应直流磁控溅射法在Al2O3基陶瓷及玻璃基底上制备了Ta-N薄膜,并对各样品的形貌结构、化学组分及电学特性进行了比较分析研究。结果表明,沉积于Al2O3陶瓷及玻璃基底的Ta-N薄膜分别呈团簇状生长与层状紧密堆积生长;Al2O3陶瓷基底沉积的Ta-N为单相薄膜,而玻璃基底上的Ta-N薄膜,随N2、Ar流量比增加,呈单相向多相共存转变;薄膜表面形貌和微结构与基底材料的原始形貌和微结构紧密相关,这说明基底材料对薄膜的形成有重要的影响;N2、Ar流量比相同时,玻璃基底上沉积的Ta-N薄膜电性能优于Al2O3基陶瓷基底上沉积的Ta-N薄膜。     

Effect of thickness on the properties of FeAlN films

The magnetic properties, microstructure, and morphology of thin nanocrystalline FeAlN films synthesized by RF magnetron sputtering were studied as dependent on the film thickness. The best soft magnetic properties were observed for the films with thicknesses above 800 nm. These films consist predominantly of nanocrystalline α-Fe particles with an average size of ∼15 nm and are characterized by crystal lattice expansion in the (110) plane approaching a critical level of 0.28%. FeAlN films with a thickness of 1000 nm are characterized by μ₁ ∼ 2000.     

高速电弧喷涂FeAlNbB非晶纳米晶涂层的组织与性能

为了提高钢铁材料的耐磨性和硬度,利用高速电弧喷涂技术在45钢基体上制备了FeAlNbB非晶纳米晶涂层.采用扫描电镜(SEM)、能谱分析仪(EDAX),透射电镜(TEM)和X射线衍射仪等设备对涂层的组织结构和相组成进行了分析,研究了非晶纳米晶的形成机制.实验结果表明:FeAlNbB非晶纳米晶涂层是非晶相、α-Fe、FeAl纳米晶和Fe3Al微晶共存的多相组织,涂层中非晶相含量约36.2%,纳米晶尺寸约14.1 nm;涂层组织均匀,结构致密,平均孔隙率约2.3%;非晶纳米晶涂层具有较高的硬度,其耐磨性是相同实验条件下制备的3Cr13涂层的2.2倍.     

Microstructure characterization in cryomilled Al 5083

Nanocrystalline metals and alloys processed by severe plastic deformation (SPD) generally have improved mechanical strength compared with conventionally processed materials. In this work, we survey the microstructure of an Al 5083 alloy prepared by ball-milling powders at cryogenic temperatures (cryomilling) then consolidated by hot-isostatic pressing (HIPing) and extrusion into cylindrical billets. After milling, the particles are comprised of nanocrystalline grains, which are maintained following extrusion. We identify MgO, Al₆(FeMnCr), Al(MnFe)Si, AlCrMg, Mg₂Si, and SiO₂ phases as precipitates or dispersoids in the microstructure. This synthesis method results in a yield strength that is approximately twice that of typical wrought Al 5083 alloys. We find that the microhardness is essentially unchanged after annealing at temperatures up to 0.8T_m. The influence of the components of the microstructure on the measured mechanical properties is discussed.     

Nb–Al–N thin films: Structural transition from nanocrystalline solid solution nc-(Nb,Al)N into nanocomposite nc-(Nb,Al)N/a–AlN

Structures and mechanical properties of thin films of the Nb–Al–N system produced by magnetron sputtering of targets from niobium and aluminum in the Ar–N₂ atmosphere have been studied. It has been shown that as the aluminum concentration increases, the structure of a thin film transforms from the nanocrystalline into the nanocomposite one, which consists of nanocrystallites of solid solutions in a matrix of amorphous aluminum nitride. Hardness, elastic modulus, and yield strength of Nb–Al–N thin films have been studied by nanoindentation in the mode of continuous control of the contact stiffness. It has been found that the transition of the structures of Nb–Al–N thin films from the nanocrystalline to the nanocomposite structures results in an increase of hardness and decrease of elastic modulus due to the formation of a thin amorphous interlayer between grains of nanocrystallites. A high hardness to elastic modulus ratio of Nb–Al–N nanocomposite thin films indicates that the films are a promising material for wear-resistant coatings.     

In-situ X-ray-diffraction studies of hydrogenated nanocrystalline gadolinium films

There is a great deal of interest in ultra-fine grained and nanocrystalline microstructure as a means of achieving enhanced strengths and interesting combinations of properties. Thin Pd-capped rare-earth metallic films switch reversibly from their initial reflecting state (metal phase) to visually transparent state (insulator or semiconductor phase) when exposed to gaseous hydrogen. Reversion to the reflecting state is achieved by exposure to air. Palladium-capped nanocrystalline gadolinium films with different grain sizes were prepared by rf-sputtering technique. Exposure of these metallic films to hydrogen resulted in formation of hydrides and increased disorder. The microstructure of the nc-Gd films were characterized by in-situ X-ray-diffraction studies during hydrogen loading. The grain size, the microstrain, and the lattice parameters were determined.     

Nanoindentation Measurements of the Mechanical Properties of Ni Thin Films: Effects of Film Microstructure and Substrate Modulus

This paper presents the results of nanoindentation measurements of the hardness and moduli of normally and obliquely deposited nanocrystalline Ni films on substrates of SiO₂, Si, and bulk Ni. Following an initial characterization of film microstructure and surface topography with atomic force microscopy (AFM), the paper examines the effects of film microstructure, film thickness, and substrate modulus on the measured film mechanical properties. Obliquely deposited films are shown to have lower hardness values than normally deposited films. The measured hardness values and material pile-up are also shown to depend significantly on the mismatch between the film modulus and substrate modulus. A framework is presented for quantifying the effects of substrate modulus mismatch on basic film mechanical properties.