scholarly journals Influence of W Addition on Microstructure and Resistance to Brittle Cracking of TiB2 Coatings Deposited by DCMS

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4664
Author(s):  
Edyta Chudzik-Poliszak ◽  
Łukasz Cieniek ◽  
Tomasz Moskalewicz ◽  
Kazimierz Kowalski ◽  
Agnieszka Kopia ◽  
...  

The aim of this work was to determine the influence of the tungsten addition to TiB2 coatings on their microstructure and brittle cracking resistance. Four coatings of different compositions (0, 7, 15, and 20 at.% of W) were deposited by magnetron sputtering from TiB2 and W targets. The coatings were investigated by the following methods: X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). All coatings had a homogeneous columnar structure with decreasing column width as the tungsten content increased. XRD and XPS analysis showed the presence of TiB2 and nonstoichiometric TiBx phases with an excess or deficiency of boron depending on composition. The crystalline size decreased from 27 nm to 10 nm with increasing W content. The brittle cracking resistance improved with increasing content of TiBx phase with deficiency of B and decreasing crystalline size.

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Angela De Bonis ◽  
Agostino Galasso ◽  
Antonio Santagata ◽  
Roberto Teghil

A MgB2target has been ablated by Nd:glass laser with a pulse duration of 250 fs. The plasma produced by the laser-target interaction, showing two temporal separated emissions, has been characterized by time and space resolved optical emission spectroscopy and ICCD fast imaging. The films, deposited on silicon substrates and formed by the coalescence of particles with nanometric size, have been analyzed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. The first steps of the films growth have been studied by Transmission Electron Microscopy. The films deposition has been studied by varying the substrate temperature from 25 to 500°C and the best results have been obtained at room temperature.


Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 612 ◽  
Author(s):  
Nancy Tepale ◽  
Víctor V. A. Fernández-Escamilla ◽  
Clara Carreon-Alvarez ◽  
Valeria J. González-Coronel ◽  
Adan Luna-Flores ◽  
...  

The fundamental aspects of the manufacturing of gold nanoparticles (AuNPs) are discussed in this review. In particular, attention is devoted to the development of a simple and versatile method for the preparation of these nanoparticles. Eco-friendly synthetic routes, such as wet chemistry and biosynthesis with the aid of polymers, are of particular interest. Polymers can act as reducing and/or capping agents, or as soft templates leading to hybrid nanomaterials. This methodology allows control of the synthesis and stability of nanomaterials with novel properties. Thus, this review focus on a fundamental study of AuNPs properties and different techniques to characterize them, e.g., Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), UV-Visible spectroscopy, Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy, Small-angle X-Ray Scattering (SAXS), and rheology. Recently, AuNPs obtained by “green” synthesis have been applied in catalysis, in medicine, and as antibacterials, sensors, among others.


Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 310 ◽  
Author(s):  
Wenhao Qian ◽  
Tao Song ◽  
Mao Ye ◽  
Haiyan Zhang ◽  
Chun Feng ◽  
...  

A facile strategy to prepare GO-based nanocomposites with both gold nanoparticles (AuNPs) and ferrocene (Fc) moieties was developed. The surface of GO was modified with PFcMAss homopolymer by surface-initiated atom transfer radical polymerization of a new methacrylate monomer of 2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocene-carboxylate (FcMAss), consisting of disulfide as an anchoring group for stabilizing AuNPs and Fc group as an additional functionality. AuNPs with an average diameter of about 4.1 nm were formed in situ on the surface of PFcMAss-decorated GO (GO-PFcMAss) via Brust-Schiffrin method to give GO-PFcMAss-AuNPs multifunctional nanocomposites bearing GO, AuNPs and Fc groups. The obtained nanocomposites were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Since disulfide-containing polymers, rather than the commonly used thiol-containing compounds, were employed as ligands to stabilize AuNPs, much more stabilizing groups were attached onto the surface of GO, and thus more AuNPs were able to be introduced onto the surface of GO. Besides, polymeric chains on the surface of GO endowed GO-PFcMAss-AuNPs nanocomposites with excellent colloidal stability, and the usage of a disulfide group provides possibility to efficiently incorporate additional functionalities by easily modifying structure of disulfide-based monomer.


2009 ◽  
Vol 24 (1) ◽  
pp. 212-216
Author(s):  
Srinivas Sathiraju ◽  
Paul N. Barnes ◽  
Robert A. Wheeler

We report the systematic substitution of Nb at the Cu1 site of YBa2Cu3Oy in thin films to form a new phase of YBa2Cu2NbO8. These films were deposited on SrTiO3(100) crystals using pulsed laser deposition and deposited at an optimal temperature of 850 °C. Films were characterized using x-ray diffraction (XRD), atomic force microscopy, x-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, and transmission electron microscopy. XRD of these films indicate c-axis oriented YBa2Cu2NbOy formation. XPS and micro-Raman spectroscopy analysis suggests Cu exists in the +2 state.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Chutima Paksunchai ◽  
Somyod Denchitcharoen ◽  
Surasing Chaiyakun ◽  
Pichet Limsuwan

Nanostructured TiCrN films were grown on Si (100) wafers by reactive DC unbalanced magnetron cosputtering technique without external heating and voltage biasing to the substrates. The effects of Ti sputtering current on the chemical composition, chemical state, electronic structure, crystal structure, and morphology of the TiCrN films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM), respectively. The results showed that all prepared films were formed as an understoichiometric (Ti, Cr)N solid solution with the fcc B1 type phase. The films exhibited a nanostructure with a crystallite size of less than 14 nm. The deconvolution of XPS spectra revealed the chemical bonding between Ti, Cr, N, and O elements. The addition of Ti contents led to the decrease of valence electrons filled in the d conduction bands which result in the change of binding energy of electrons in core levels. The roughness of the films was found to increase with increasingITi. The cross-sectional morphology of the films showed columnar structure with dome tops.


2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.


Nanomedicine ◽  
2022 ◽  
Author(s):  
Hossein Danafar ◽  
Marziyeh Salehiabar ◽  
Murat Barsbay ◽  
Hossein Rahimi ◽  
Mohammadreza Ghaffarlou ◽  
...  

Aim: To prepare a novel hybrid system for the controlled release and delivery of curcumin (CUR). Methods: A method for the ultrasound-assisted fabrication of protein-modified nanosized graphene oxide-like carbon-based nanoparticles (CBNPs) was developed. After being modified with bovine serum albumin (BSA), CUR was loaded onto the synthesized hybrid (labeled CBNPs@BSA–CUR). The structure and properties of the synthesized nanoparticles were elucidated using transmission electron microscopy (TEM), atomic force microscopy (AFM), ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) methods. Results: CBNPs@BSA–CUR showed pH sensitivity and were calculated as controlled CUR release behavior. The drug-free system exhibited good biocompatibility and was nontoxic. However, CBNPs@BSA–CUR showed acceptable antiproliferative ability against MCF-7 breast cancer cells. Conclusion: CBNPs@BSA–CUR could be considered a highly promising nontoxic nanocarrier for the delivery of CUR with good biosafety.


2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.


2016 ◽  
Vol 689 ◽  
pp. 55-59
Author(s):  
Serge Zhuiykov

Electrical properties and morphology of orthorhombic β–WO3 nano-flakes with thickness of ~7-9 nm were investigated at the nanoscale using energy dispersive X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNATM). CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nano-flakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β–WO3 nano-flakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro- and nano-structured WO3 synthesized at alternative temperatures.


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