scholarly journals Dealloying of gold–copper alloy nanowires: From hillocks to ring-shaped nanopores

2016 ◽  
Vol 7 ◽  
pp. 1361-1367 ◽  
Author(s):  
Adrien Chauvin ◽  
Cyril Delacôte ◽  
Mohammed Boujtita ◽  
Benoit Angleraud ◽  
Junjun Ding ◽  
...  
Keyword(s):  
Copper Alloy ◽  
Surface Defects ◽  
Complex Surface ◽  
Metal Nanowires ◽  
Gold Nanowires ◽  
Porous Gold ◽  
Gold Silver ◽  
Nodular Growth ◽  
Alloy Nanowires ◽  
High Roughness

We report on a novel fabrication approach of metal nanowires with complex surface. Taking advantage of nodular growth triggered by the presence of surface defects created intentionally on the substrate as well as the high tilt angle between the magnetron source axis and the normal to the substrate, metal nanowires containing hillocks emerging out of the surface can be created. The approach is demonstrated for several metals and alloys including gold, copper, silver, gold–copper and gold–silver. We demonstrate that applying an electrochemical dealloying process to the gold–copper alloy nanowire arrays allows for transforming the hillocks into ring-like shaped nanopores. The resulting porous gold nanowires exhibit a very high roughness and high specific surface making of them a promising candidate for the development of SERS-based sensors.

scholarly journals Large-Scale Fabrication of Porous Gold Nanowires via Laser Interference Lithography and Dealloying of Gold–Silver Nano-Alloys

Micromachines ◽  
2017 ◽  
Vol 8 (6) ◽  
pp. 168 ◽  
Author(s):  
Adrien Chauvin ◽  
Nicolas Stephant ◽  
Ke Du ◽  
Junjun Ding ◽  
Ishan Wathuthanthri ◽  
...  
Keyword(s):  
Large Scale ◽  
Interference Lithography ◽  
Gold Nanowires ◽  
Laser Interference Lithography ◽  
Laser Interference ◽  
Porous Gold ◽  
Gold Silver

scholarly journals Laser Polishing of Ti6Al4V Fabricated by Selective Laser Melting

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 191 ◽  
Author(s):  
Chunyong Liang ◽  
Yazhou Hu ◽  
Ning Liu ◽  
Xianrui Zou ◽  
Hongshui Wang ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Surface Defects ◽  
Fatigue Behavior ◽  
Osteoblastic Differentiation ◽  
Laser Melting ◽  
Laser Polishing ◽  
Laser Process ◽  
High Roughness ◽  
Dental Applications

Selective laser melting (SLM) is emerging as a promising 3D printing method for orthopedic and dental applications. However, SLM-based Ti6Al4V components frequently exhibit high roughness values and partial surface defects. Laser polishing (LP) is a newly developed technology to improve the surface quality of metals. In this research, LP is applied to improve the surface finish of components. The results show that the laser beam can neatly ablate the aggregates of metallic globules and repair cracks and pores on the surface, resulting in a smooth surface with nanocomposites. Overall, the results indicate that using LP optimizes surface morphology to favor fatigue behavior and osteoblastic differentiation. These findings provide foundational data to improve the surface roughness of a laser-polished implant and pave the way for optimized mechanical behavior and biocompatibility via the laser process.

Facet Formation on Single Crystal TiO2 Surfaces Studied by Atomic Force Microscopy

1991 ◽  
Vol 237 ◽  
Author(s):  
M. D. Antonik ◽  
J. C. Edwards ◽  
R. J. Lad
Keyword(s):  
Atomic Force Microscopy ◽  
Single Crystal ◽  
Surface Defects ◽  
Complex Surface ◽  
Force Microscopy ◽  
Aspect Ratios ◽  
Atomic Force ◽  
Small Height ◽  
Low Energy Electron ◽  
Large Distribution

ABSTRACTAtomic force microscopy (AFM) and low energy electron diffraction (LEED) have been used to study the faceting behavior on (001) and (100) surfaces of a TiO2 single crystal. On the TiO2 (001) surface, LEED patterns characteristic of {011} facet planes develop after annealing below 900 °C in agreement with previous studies, but AFM shows a complex surface morphology consisting of a large distribution of facet sizes and orientations. After annealing at 1300 °C, facets do not form but rather a network of 5 – 30 nm high ridges develops over the entire surface. These ridges may be the result of surface defects produced by changes in bulk stoichiometry during annealing. On the TiO2 (100) surface, facets are also observed after annealing below 900 °C. However, these facets have extremely small height to width aspect ratios and are not discernible with LEED.

Porous Gold Nanowires: Plasmonic Response and Surface-Enhanced Infrared Absorption

2016 ◽  
Vol 4 (11) ◽  
pp. 1838-1845 ◽  
Author(s):  
Ina Schubert ◽  
Christian Huck ◽  
Philipp Kröber ◽  
Frank Neubrech ◽  
Annemarie Pucci ◽  
...  
Keyword(s):  
Infrared Absorption ◽  
Gold Nanowires ◽  
Porous Gold ◽  
Surface Enhanced

scholarly journals Classification of Magnetic Tile Surface Defects Based on Efficientnet Network with Attention

2021 ◽  
Vol 2137 (1) ◽  
pp. 012062
Author(s):  
Chengshuai Fan
Keyword(s):  
Classification Accuracy ◽  
Surface Defects ◽  
Learning Algorithm ◽  
Complex Surface ◽  
Detection Algorithm ◽  
Image Features ◽  
Low Contrast ◽  
Deep Learning Algorithm ◽  
Model Size

Abstract The magnetic tile image has the characteristics of uneven illumination, complex surface texture, and low contrast. Aiming at the problem that the traditional defect detection algorithm is difficult to accurately identify the defects, and the deep learning algorithm is difficult to balance the classification accuracy and the size of the speed model, a defect classification algorithm based on attention-based EfficientNet is proposed. The algorithm first enhances the network’s spatial and location information for image features by integrating the Convolutional Block Attention Module, and improves the network’s ability to identify defects. Then, on this basis, Criss-Cross Attention is added to the network, so that the network can better the context information of the horizontal and vertical cross of image features, so that each pixel can finally capture the full image dependency of all pixels. Experimental results show that the algorithm has higher classification accuracy than EfficientNet-B0, reached 99.11%, and has a better balance between accuracy, speed and model size than other classification models.

Comparative study of how additives affect sintered silver microstructure in die-attach applications

2019 ◽  
Vol 2019 (HiTen) ◽  
pp. 000061-000065
Author(s):  
Ming Lo ◽  
Seyed Amir Paknejad ◽  
Harry Borrill ◽  
Wan K. Kong ◽  
Addo Addo-Kwabena ◽  
...  
Keyword(s):  
New Technology ◽  
Thermal Ageing ◽  
Chemical Characteristics ◽  
Ag Nanoparticle ◽  
Porous Gold ◽  
Die Attach ◽  
Gold Silver ◽  
Wide Range ◽  
Physical And Chemical

Abstract Die attach materials based on silver nanoparticles which sinter at temperatures in the range 200–300 °C are a comparatively new technology. The properties of the sintered structure can be affected by a wide range of additives which can alter the physical and chemical characteristics of the joints. In this study, a commercially available Ag nanoparticle paste has been used as the base, and a range of additives have been added principally to determine the effect of each additive on the sintered microstructure immediately after sintering, and after long term thermal ageing. The additives trialled include Au, Sn, Cu, and Zn. In each case the additive powder was mixed with the original paste and the microstructure after sintering was compared to the microstructure after ageing at 250 °C for 24 h. Another method of introducing an additive into the system is adding it as a mesh, interposed between die and substrate and immersed in the silver paste. Au was added in both this form, and in the form of a powder additive. The mesh results in a thermodynamically stable microstructure up to at least 500 °C. The design takes advantage of solid–solid interdiffusion bonding which results in a die attach assembly with a continuous, non-porous gold-silver interdiffusion layer running all the way from the die to the substrate.

scholarly journals Versatile method for template-free synthesis of single crystalline metal and metal alloy nanowires

Nanoscale ◽  
2016 ◽  
Vol 8 (5) ◽  
pp. 2804-2810 ◽  
Author(s):  
John A. Scott ◽  
Daniel Totonjian ◽  
Aiden A. Martin ◽  
Toan Trong Tran ◽  
Jinghua Fang ◽  
...  
Keyword(s):  
Metal Alloy ◽  
Solution Phase ◽  
Metal Nanowires ◽  
Growth Technique ◽  
Single Crystalline ◽  
Alloy Nanowires ◽  
Template Free ◽  
Free Growth ◽  
Crystalline Metal

A versatile, template-free growth technique for single crystalline metal nanowires using gas or solution phase precursors.

scholarly journals Gold-Silver Alloy Nanowires Electrochemically Grown in the Nanopores of Aluminum Anodic Oxidation Film from Cyanide-Free Bath and Their Color Properties

2006 ◽  
Vol 57 (9) ◽  
pp. 670-675 ◽  
Author(s):  
Akihito YASUI ◽  
Toshikazu KANOH ◽  
Mitsunobu IWASAKI ◽  
Tetsuro KAWAHARA ◽  
Subbian KARUPPUCHARMY ◽  
...  
Keyword(s):  
Anodic Oxidation ◽  
Silver Alloy ◽  
Color Properties ◽  
Gold Silver ◽  
Alloy Nanowires

Segregation of Fission Products to Surfaces of UO2

2000 ◽  
Vol 654 ◽  
Author(s):  
C.R. Stanek ◽  
Robin W. Grimes ◽  
Mark R. Bradford
Keyword(s):  
Fission Product ◽  
Oxygen Vacancies ◽  
Surface Defects ◽  
Repeat Unit ◽  
Fission Products ◽  
Complex Surface ◽  
Surface Structures ◽  
Release Rates ◽  
Single Oxygen ◽  
Charged Defects

AbstractIn order to predict the release rates of fission products from UO2 nuclear fuel, it is necessary to determine the energetics associated with their segregation from the bulk to surfaces. Here segregation is determined by calculating the total energy of a simulation repeat unit which includes a fission product, as a function of the distance of the fission product from the surface. We have investigated the possibility that specific fission products segregate preferentially to certain surfaces. In particular, Ce4+ and Zr4+ segregate to the (100) surface, while Ba2+ and Sr2+ segregate to the (111) surface. Two issues make these calculations more complex. First, charged defects need to be compensated by oxygen vacancies. For example, divalent Ba2+ and Sr2+ substituting on uranium sites are compensated by a single oxygen vacancy. Second, certain surfaces, such as the (100), are inherently unstable, but can be stabilized by oxygen vacancies. Arrangements of these surface defects lead to complex surface structures that affect segregation energetics.

scholarly journals Testing New Coatings for Outdoor Bronze Monuments: A Methodological Overview

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 131
Author(s):  
Paola Letardi
Keyword(s):  
Copper Alloy ◽  
Complex Surface ◽  
Special Focus ◽  
Efficacy Evaluation ◽  
Acceptable Solution ◽  
Methodological Choices ◽  
Cleaning Methods ◽  
New Treatments ◽  
Selection Of

Coatings to be used for cultural heritage protection face peculiar challenges. In the last few decades, several projects addressed the issue of new treatments in the field of copper alloy artworks. Nonetheless, no one has yet been recognised as a more acceptable solution with respect to traditional choices, with their known limits. The lack of standard methods to test new coatings that can be effectively applied to artworks make it more difficult to compare different studies and open the way to practical use in restoration. Over the years, several issues have gradually been better focused, even though they are not yet widely considered in new coatings efficacy evaluation for application on copper alloy artifacts. They are mainly linked to the quite complex surface of this category of heritage objects and the role it plays on coating effectiveness. An overview of the variety of relevant surface properties is provided (presence of corrosion products and old protective treatments, cleaning methods, surface unevenness, just to name a few) with a special focus on the role of coating performance. Some methodological choices are discussed for the selection of mock-ups, testing techniques and weathering procedures, with peculiar attention to comparison with real artworks.

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