原子层沉积PI修饰摩擦纳米发电机的研究

我们通过旋涂法在铜片表面制备出一层PVDF薄膜,并通过原子层沉积技术进行表面修饰,以PMMA和EDA为原料,在制备出的微纳米孔PVDF表面沉积不同厚度的聚酰亚胺(PI)。PI是一种电负性较强的材料,通过沉积不同厚度的PI,并以其作为摩擦层制备摩擦纳米发电机,通过对器件的输出电压和输出电流检测,我们发现通过原子层沉积PI修饰摩擦层表面的微纳米结构能够有效提高器件的输出性能。     

纳米金刚石含量对电沉积在45碳钢表面的复合镀层性能的影响

采用直流电沉积方式,研究镀液中纳米金刚石浓度对45#钢基体上电沉积制备镍/纳米金刚石复合镀层性能的影响规律.采用线性扫描伏安法,探讨了镀液中纳米金刚石浓度的Ni2+阴极还原行为,用数显立式光学计以及DU H-W201型显微硬度计测试镀层厚度、显微硬度,以及用扫描电镜对复合镀层形貌及组分进行分析.实验结果表明,随着镀液中...     

电沉积纳米复合镀层的研究现状

纳米复合电沉积是一种新兴的复合表面技术。阐述了纳米颗粒与金属共沉积的机理、工艺条件对纳米复合电沉积的影响。以及纳米复合共沉积的应用。纳米与金属共沉积可明显提高镀层的硬度、耐磨、耐蚀、光催化和电接触性能。指出了纳米复合电沉积现存的问题，并为今后的研究提出了建议。     

工艺条件对电沉积Ni-金刚石复合镀层性能的影响

研究了温度、电流密度、pH等工艺条件对镍-金刚石复合镀层性能的影响。实验表明,在金刚石含量为40 g/L的瓦特镀镍液中,当电流密度为1.5 A/dm2、温度为40℃、pH为3.8时,在45#钢上可获得性能较好的镍-金刚石复合镀层,且沉积速率适中。镀层中金刚石微粒含量为11%~13%(质量分数),镀层硬度为2100 MPa左右,耐磨性能较好。     

大尺寸陶瓷膜原子层沉积过程的CFD模拟

陶瓷膜具有耐高温、耐酸碱、强度高等优点,在液体分离领域得到了广泛应用。对陶瓷膜进行表面改性,可进一步提升其性能,但基于表面化学反应的改性方法工艺过程复杂,难于控制。原子层沉积（atomic layer deposition,ALD）是基于表面自限制化学反应过程的气固相薄膜沉积技术,可以在纳米尺度精确调控孔道结构,特别适用于多孔分离膜的改性和功能化。目前尚无适用于大尺寸陶瓷膜的ALD设备,需要对ALD过程进行专门的优化设计。通过CFD模型对1 m长的单通道陶瓷膜的ALD过程进行了研究,在数学模型中考虑了两种气体源交替进入腔体中所引发不同的表面反应,并考虑了脉冲边界的影响。模拟计算结果与实验比较平均相对误差为1.69%。在数值模拟的基础上,提出了双向交替旋转脉冲的ALD模式,为陶瓷膜的ALD沉积改性的装备设计和过程优化提供了理论依据。     

电沉积纳米晶镍制备金刚石工具

介绍了纳米晶镍作为新型胎体材料制备电镀金刚石工具的方法及其特点.纳米晶镍是在瓦特型槽液中通过调整方波电流而得到的,脉冲参数为:电流导通时间3 ms,关断时间45 ms,峰值电流密度100 A·dm-2.其显微硬度达到595 MPa,没有气孔之类缺陷,表面较平整,晶粒尺寸在50 nm左右.工具平均寿命要比常用的Ni-Co胎体材料工具高15.8%.新工艺还有其它诸多优点,如生产周期短、所用试剂的成本低、电解液成分简单等.电镀纳米晶体材料作为金刚石工具的胎体材料是较为理想的.     

原子层沉积构建高性能催化剂的研究进展

催化剂在能源化工领域具有重要应用,精确设计及调控催化剂结构可有效改善催化剂的性能。原子层沉积（ALD）是基于饱和自限制的气-固界面反应技术,被认为是调控活性相的组成、尺寸及落位最有效的方式之一。本文综述了ALD技术在调控催化剂活性相结构、设计多功能型催化剂及提高催化剂稳定性等方面的研究进展。重点阐述了ALD技术在调控催化剂活性相颗粒尺寸和表界面结构、设计多功能核壳结构及多孔材料限制性催化剂等方面的应用。ALD设计及控制金属沉积的技术优势可实现对催化剂活性、产物选择性和稳定性的有效调控,但其在复杂结构载体的沉积机理方面仍未得到充分研究,是今后研究工作重点。此外,利用ALD技术设计结构清晰、功能多样的催化剂来进一步提高催化性能及认识其反应机理也是未来的研究方向。     

电沉积纳米镍-钴合金制备金刚石工具

介绍了采用纳米镍-钴镀层作为新型胎体材料,制备电镀金刚石工具的方法及其特点.纳米镀层是在瓦特型槽液中通过方波电流而得到的,脉冲参数为电流导通时间1 ms,电流关断时间15 ms,峰值电流密度100 A/dm2.镀层中钴的质量分数量为8.5%,表面较光整,晶粒尺寸在15 nm左右,显微硬度达到6 000 MPa,与纯镍纳米镀层的相近,但抗拉强度明显高于纯镍纳米镀层的.由其制得的工具平均寿命比纯镍纳米胎体材料工具高15.5%.     

Nanopatterning by direct-write atomic layer deposition

A novel direct-write approach is presented, which relies on area-selective atomic layer deposition on seed layer patterns deposited by electron beam induced deposition. The method enables the nanopatterning of high-quality material with a lateral resolution of only ～10 nm. Direct-write ALD is a viable alternative to lithography-based patterning with a better compatibility with sensitive nanomaterials.     

Two-step growth of ZnO films on silicon by atomic layer deposition

Two-step growth of ZnO by atomic layer deposition at low temperatures was performed to grow quality ZnO films on silicon substrates: first, the growth of a buffer layer at 130 ?C and second, the growth of the main layer at 210 ?C. Structural and optical properties of the ZnO films deposited on ZnO-buffer/Si(111) were investigated as a function of buffer layer thickness. The films showed a strong UV emission at 380 nm and a weak green emission at 520–570 nm. The ZnO films deposited on a 327 å buffer layer showed overall the best surface morphology and structural and optical properties.     

Iridium wire grid polarizer fabricated using atomic layer deposition

In this work, an effective multistep process toward fabrication of an iridium wire grid polarizer for UV applications involving a frequency doubling process based on ultrafast electron beam lithography and atomic layer deposition is presented. The choice of iridium as grating material is based on its good optical properties and a superior oxidation resistance. Furthermore, atomic layer deposition of iridium allows a precise adjustment of the structural parameters of the grating much better than other deposition techniques like sputtering for example. At the target wavelength of 250 nm, a transmission of about 45% and an extinction ratio of 87 are achieved.     

Robust nanoporous alumina monoliths by atomic layer deposition on low-density carbon-nanotube scaffolds

Synthesis of nanoporous alumina monoliths with controlled morphology and density is a challenge. Here, we demonstrate mechanically robust alumina monoliths synthesized by conformal overcoating of graphitic nanoligaments of low-density carbon-nanotube-based aerogels (CNT-CAs) by using atomic layer deposition. Young’s modulus of resultant monoliths increases superlinearly with the monolith density with an exponent of ∼2.4, defined by the morphology and connectivity of the CNT-CA scaffold. As a result, for a given monolith density, alumina-carbon composites have moduli comparable to those of CNT-CAs and significantly superior to those of pure alumina aerogels reported previously.     

Electrodeposition of Ru by atomic layer deposition (ALD)

Studies are presented describing attempts to form a cycle for the growth of Ru nanofilms using the electrochemical form of atomic layer deposition (ALD). Au substrates have been used to form Ru nanofilms, based on layer by layer growth of deposits, using surface limited reactions. These deposits were formed using surface limited redox replacement (SLRR), where an atomic layer of a sacrificial element is first deposited by underpotential deposition (UPD), and is then exchanged for the element of interest. The use of the UPD atomic layer limits subsequent growth by limiting the number of electrons available for deposition. In the present study, Pb atomic layers were used, and exposed to solutions of Ru³⁺ ions at open circuit. This process can then be repeated to grow films of the desired thickness. It was shown that less than an at.% of Pb was evident in the deposits, using electron probe microanalysis (EPMA), and even that could be removed if a stripping step was added to the ALD cycle. The deposits displayed the expected Ru voltammetry, as well as the Ru hcp XRD pattern. There were some differences in the first 20 cycles, compared with subsequent, suggesting some nucleation process that must be investigated. However, after 20 cycles, the deposit showed the linear growth with the number of cycles expected for an ALD process. The morphology of Ru films, deposited on template-stripped Au was studied using ex situ scanning tunneling microscopy (STM), and showed no evidence of 3D growth.     

Characterization of silicon films grown by atomic layer deposition on nanocrystalline diamond

Ultrathin silicon films were deposited on nanocrystalline diamonds by means of atomic layer deposition (ALD) from gaseous monosilane. The silicon deposition was achieved through the sequential reaction of SiH₄ saturated adsorption and in-site pyrogenation. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution electron microscopy (HREM) and Fourier transform infrared (FTIR) spectra were utilized to investigate the structure and the morphology of Si-coated nanocrystalline diamonds. The results confirmed that continuous silicon films were successfully deposited on both basal planes and edges of nanocrystalline diamond particles by this ALD method and the structure of the film was mainly determined by deposition temperature and deposition cycle.     

Nanoengineering and interfacial engineering of photovoltaics by atomic layer deposition

Investment into photovoltaic (PV) research has accelerated over the past decade as concerns over energy security and carbon emissions have increased. The types of PV technology in which the research community is actively engaged are expanding as well. This review focuses on the burgeoning field of atomic layer deposition (ALD) for photovoltaics. ALD is a self-limiting thin film deposition technique that has demonstrated usefulness in virtually every sector of PV technology including silicon, thin film, tandem, organic, dye-sensitized, and next generation solar cells. Further, the specific applications are not limited. ALD films have been deposited on planar and nanostructured substrates and on inorganic and organic devices, and vary in thickness from a couple of angstroms to over 100 nm. The uses encompass absorber materials, buffer layers, passivating films, anti-recombination shells, and electrode modifiers. Within the last few years, the interest in ALD as a PV manufacturing technique has increased and the functions of ALD have expanded. ALD applications have yielded fundamental understanding of how devices operate and have led to increased efficiencies or to unique architectures for some technologies. This review also highlights new developments in high throughput ALD, which is necessary for commercialization. As the demands placed on materials for the next generation of PV become increasingly stringent, ALD will evolve into an even more important method for research and fabrication of solar cell devices.     

Modification of interparticle forces for nanoparticles using atomic layer deposition

Silica and titania nanoparticles were individually coated with ultrathin alumina films using atomic layer deposition (ALD) in a fluidized bed reactor. The effect of the coating on interparticle forces was studied. Coated particles showed increased interactions which impacted their flowability. This behavior was attributed to modifications of the Hamaker coefficient and the size of nanoparticles. Stronger interparticle forces translated into a larger mean aggregate size during fluidization, which increased the minimum fluidization velocity. A lower bed expansion was observed for coated particles due to enhanced interparticle forces that increased the cohesive strength of the bed. Increased cohesiveness of coated powders was also determined through angle of repose and Hausner index measurements. The dispersability of nanopowders was studied through sedimentation and z-potential analysis. The optimum dispersion conditions and isoelectric point of nanoparticle suspensions changed due to the surface modification. A novel atomic force microscope (AFM) technique was used to directly measure interactions between nanoparticles dispersed on a flat substrate and the tip of an AFM cantilever. Both Van der Waals and electrostatic interactions were detected during these measurements. Long and short range interactions were modified by the surface coating.     

原子层沉积技术在银工艺饰品抗变色中的应用

分析了电镀贵金属、无机钝化膜、有机保护膜等几类常见银合金表面处理方法的特点及存在的问题,概述了原子层沉积技术的发展背景、基本原理、工艺特点、研究及应用状况,介绍了该技术应用于银工艺饰品抗变色上的效果.