scholarly journals Effect of Cast Defects on the Corrosion Behavior and Mechanism of UNS C95810 Alloy in Artificial Seawater

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1790 ◽  
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Jintao Wang ◽  
Zhanping Zhang ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Laser Scanning ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Testing ◽  
Alloy Microstructure

To study the effect of cast defects on the corrosion behavior and mechanism of the UNS C95810 alloy in seawater, an investigation was conducted by weight loss determination, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD) and electrochemical testing of the specimen with and without cast defects on the surface. The results show that the corrosion rate of the alloy with cast defects is higher than that of the alloy without cast defects, but the defects do not change the composition of the resulting corrosion products. The defects increase the complexity of the alloy microstructure and the tendency toward galvanic corrosion, which reduce the corrosion potential from −3.83 to −86.31 mV and increase the corrosion current density from 0.228 to 0.23 μA⋅cm−2.

scholarly journals Biogenic Gold Nanoparticles as Potent Antibacterial and Antibiofilm Nano-Antibiotics against Pseudomonas aeruginosa

Antibiotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 100 ◽  
Author(s):  
Syed Ghazanfar Ali ◽  
Mohammad Azam Ansari ◽  
Mohammad A. Alzohairy ◽  
Mohammad N. Alomary ◽  
Sami AlYahya ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Gold Nanoparticles ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Tinospora Cordifolia ◽  
Confocal Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Size

Abstract: Plant-based synthesis of eco-friendly nanoparticles has widespread applications in many fields, including medicine. Biofilm—a shield for pathogenic microorganisms—once formed, is difficult to destroy with antibiotics, making the pathogen resistant. Here, we synthesized gold nanoparticles (AuNPs) using the stem of an Ayurvedic medicinal plant, Tinospora cordifolia, and studied the action of AuNPs against Pseudomonas aeruginosa PAO1 biofilm. The synthesized AuNPs were characterized by techniques such as ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray diffraction, X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy. The AuNPs were spherically shaped with an average size of 16.1 nm. Further, the subminimum inhibitory concentrations (MICs) of AuNPs (50, 100, and 150 µg/mL) greatly affected the biofilm-forming ability of P. aeruginosa, as observed by crystal violet assay and SEM, which showed a decrease in the number of biofilm-forming cells with increasing AuNP concentration. This was further justified by confocal laser scanning microscopy (CLSM), which showed irregularities in the structure of the biofilm at the sub-MIC of AuNPs. Further, the interaction of AuNPs with PAO1 at the highest sub-MIC (150 µg/mL) showed the internalization of the nanoparticles, probably affecting the tendency of PAO1 to colonize on the surface of the nanoparticles. This study suggests that green-synthesized AuNPs can be used as effective nano-antibiotics against biofilm-related infections caused by P. aeruginosa.

Investigation of HgBr x I 2-x using confocal laser scanning microscopy and x-ray diffraction

1998 ◽  
Author(s):  
George A. Stanciu ◽  
J. L. Oud ◽  
E. K. Polychronyadis ◽  
Maria Daviti ◽  
Angelia Stanciu ◽  
...  
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser ◽  
X Ray Diffraction ◽  
X Ray

Application of levitation melting to the separation of oxide inclusions from nitrides and carbides in Ni-based superalloy

2020 ◽  
Vol 117 (2) ◽  
pp. 206
Author(s):  
Xiaoyong Gao ◽  
Lin Zhang ◽  
Xuanhui Qu ◽  
Yifeng Luan ◽  
Xiaowei Chen
Keyword(s):  
Laser Scanning ◽  
Separation Efficiency ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Separation Mechanism ◽  
X Ray Diffraction ◽  
Levitation Melting ◽  
X Ray ◽  
Automated Scanning

Oxides are usually surrounded by nitrides and carbides in superalloys, which contain high Ti and Nb contents. This makes it difficult to precisely characterize oxide size and composition. Separation of oxides from nitrides and carbides in FGH96 superalloy was carried out by levitation melting to accurately characterize oxides. Manual and automated scanning electron microscopy and energy-dispersive X-ray spectroscopy observations as well as X-ray diffraction were used to characterize inclusions. In the billet, nearly all oxides were surrounded by nitrides and carbides. After levitation melting, however, the majority of oxides were separated, agglomerated and floated to the top surface. The separation efficiency of oxides from nitrides is approximately 85.5%. Oxides were determined as MgO-Al2O3 spinel with the size of 1∼10 µm. Finally, in situ confocal laser scanning microscopy clarified the separation mechanism.

scholarly journals Investigation of Spin Coating Cerium-Doped Hydroxyapatite Thin Films with Antifungal Properties

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 464
Author(s):  
Simona Liliana Iconaru ◽  
Mihai Valentin Predoi ◽  
Patrick Chapon ◽  
Sofia Gaiaschi ◽  
Krzysztof Rokosz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Spin Coating ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
X Ray ◽  
Antifungal Properties ◽  
Scanning Electron

In this study, the cerium-doped hydroxyapatite (Ca10−xCex(PO4)6(OH)2 with xCe = 0.1, 10Ce-HAp) coatings obtained by the spin coating method were presented for the first time. The stability of the 10Ce-HAp suspension particles used in the preparation of coatings was evaluated by ultrasonic studies, transmission electron microscopy (TEM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The surface morphology of the 10Ce-HAp coating was studied by SEM and atomic force microscopy (AFM) techniques. The obtained 10Ce-HAp coatings were uniform and without cracks or unevenness. Glow discharge optical emission spectroscopy (GDOES) and X-ray photoelectron spectroscopy (XPS) were used for the investigation of fine chemical depth profiling. The antifungal properties of the HAp and 10Ce-HAp suspensions and coatings were assessed using Candida albicans ATCC 10231 (C. albicans) fungal strain. The quantitative antifungal assays demonstrated that both 10Ce-HAp suspensions and coatings exhibited strong antifungal properties and that they successfully inhibited the development and adherence of C. albicans fungal cells for all the tested time intervals. The scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) visualization of the C. albicans fungal cells adherence to the 10Ce-HAp surface also demonstrated their strong inhibitory effects. In addition, the qualitative assays also suggested that the 10Ce-HAp coatings successfully stopped the biofilm formation.

scholarly journals Influence of Salt Support Structures on Material Jetted Aluminum Parts

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4072
Author(s):  
Benedikt Kirchebner ◽  
Maximilian Ploetz ◽  
Christoph Rehekampff ◽  
Philipp Lechner ◽  
Wolfram Volk
Keyword(s):  
Molten Salts ◽  
Laser Scanning ◽  
Water Soluble ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Support Structures ◽  
Micro Hardness ◽  
X Ray ◽  
Melting Temperatures ◽  
Economic Support

Like most additive manufacturing processes for metals, material jetting processes require support structures in order to attain full 3D capability. The support structures have to be removed in subsequent operations, which increases costs and slows down the manufacturing process. One approach to this issue is the use of water-soluble support structures made from salts that allow a fast and economic support removal. In this paper, we analyze the influence of salt support structures on material jetted aluminum parts. The salt is applied in its molten state, and because molten salts are typically corrosive substances, it is important to investigate the interaction between support and build material. Other characteristic properties of salts are high melting temperatures and low thermal conductivity, which could potentially lead to remelting of already printed structures and might influence the microstructure of aluminum that is printed on top of the salt due to low cooling rates. Three different sample geometries have been examined using optical microscopy, confocal laser scanning microscopy, energy-dispersive X-ray spectroscopy and micro-hardness testing. The results indicate that there is no distinct influence on the process with respect to remelting, micro-hardness and chemical reactions. However, a larger dendrite arm spacing is observed in aluminum that is printed on salt.

scholarly journals Effect of Sn Addition on Microstructure and Corrosion Behavior of As-Extruded Mg–5Zn–4Al Alloy

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2069 ◽  
Author(s):  
Jian Ding ◽  
Xin Liu ◽  
Yujiang Wang ◽  
Wei Huang ◽  
Bo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Corrosion Current ◽  
Electrochemical Measurements ◽  
Corrosion Mechanism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Average Grain Size

The effect of Sn addition on the microstructure and corrosion behavior of extruded Mg–5Zn–4Al–xSn (0, 0.5, 1, 2, and 3 wt %) alloys was investigated by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical measurements, and immersion tests. Microstructural results showed that the average grain size decreased to some degree and the amount of precipitates increased with the increasing amount of Sn. The extruded Mg–5Zn–4Al–xSn alloy mainly consisted of α-Mg, Mg32(Al,Zn)49, and Mg2Sn phases as the content of Sn was above 1 wt %. Electrochemical measurements indicated that the extruded Mg–5Zn–4Al–1Sn (ZAT541) alloy presented the best corrosion performances, with corrosion potential (Ecorr) and corrosion current density (Icorr) values of −1.3309 V and 6.707 × 10−6 A·cm−2, respectively. Furthermore, the corrosion mechanism of Sn is discussed in detail.

Microcontact Printed Protein Micropatterns on Titanium Surface Characterized by Confocal Laser Scanning Microscopy

2012 ◽  
Vol 487 ◽  
pp. 730-734 ◽  
Author(s):  
Chang Jiang Pan ◽  
Yu Dong Nie ◽  
Yun Xiao Dong
Keyword(s):  
Laser Scanning ◽  
Photoelectron Spectrum ◽  
Titanium Surface ◽  
Microcontact Printing ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Water Contact ◽  
X Ray ◽  
Replication Errors ◽  
Titanium Surfaces

In this paper, two kinds of stamps (squares (a×a)) separated by spacing b, the values of a and b were varied from 2.5 µm to 50 µm), i.e. positive and negative stamps, were prepared. The stamps inked with the rhodamine-labeled bovine serum albumin (BSA) were then microcontacted with the aldehyde-functionalized titanium surfaces. Water contact angle and X-ray photoelectron spectrum (XPS) indicated that BSA can be covalently immobilized on aldehyde modified titanium surface by microcontact printing. The experimental results of CLSM showed that the patterns with resolution from 2.5 µm to 50 µm were obtained successfully. Both positive stamp and negative stamp were deformed when the value of a was less than or equal to 5 µm, which resulted in replication errors. Furthermore, the larger spacing (50 µm) resulted in stamp collapse when the value a of the positive stamp was less than or equal to 10 µm, leading to whole fluorescence on substrates.

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