scholarly journals Optimization of Ruthenium Dioxide Solid Contact in Ion-Selective Electrodes

Membranes ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 182 ◽  
Author(s):  
Nikola Lenar ◽  
Beata Paczosa-Bator ◽  
Robert Piech
Keyword(s):  
Potentiometric Sensors ◽  
Ruthenium Dioxide ◽  
Ion Selective Electrodes ◽  
Electrical Capacitance ◽  
Hydrophobic Properties ◽  
Hydration Properties ◽  
Structural Water ◽  
X Ray ◽  
Electrochemical Tests ◽  
Porous Microstructure

Ruthenium dioxide occurs in two morphologically varied structures: anhydrous and hydrous form; both of them were studied in the scope of this work and applied as mediation layers in ion-selective electrodes. The differences between the electrochemical properties of those two materials underlie their diverse structure and hydration properties, which was demonstrated in the paper. One of the main differences is the occurrence of structural water in RuO2•xH2O, which creates a large inner surface available for ion transport and was shown to be a favorable feature in the context of designing potentiometric sensors. Both materials were examined with SEM microscope, X-ray diffractometer, and contact angle microscope, and the results revealed that the hydrous form can be characterized as a porous structure with a smaller crystallite size and more hydrophobic properties contrary to the anhydrous form. Potentiometric and electrochemical tests carried out on designed GCD/RuO2/K+-ISM and GCD/RuO2•xH2O/K+-ISM electrodes proved that the loose porous microstructure with chemically bounded water, which is characteristic for the hydrous form, ensures the high electrical capacitance of electrodes (up to 1.2 mF) with consequently more stable potential (with the potential drift of 0.0015 mV/h) and a faster response (of a few seconds).

scholarly journals Gas Transfer of Metals during the Destruction of Efflorescent Sulfates from the Belovo Plant Sulfide Slag, Russia

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 344
Author(s):  
Svetlana Bortnikova ◽  
Natalya Abrosimova ◽  
Nataliya Yurkevich ◽  
Valentina Zvereva ◽  
Anna Devyatova ◽  
...  
Keyword(s):  
Major And Trace Elements ◽  
Water Molecules ◽  
Gas Transfer ◽  
Structural Water ◽  
Fermentation Products ◽  
X Ray ◽  
Gas Condensates ◽  
Gas Phase Transport ◽  
Phase Transport

This paper demonstrates the results of experiments for the determination of the composition of gases during the dehydration of sulfates (Na-jarosite, melanterite, and chalcanthite) collected at the surface of pyrometallurgical waste heaps. The volatilization of various elements, and vapor–gas phase transport from three sulfate groups were investigated by stepwise laboratory heating at 45, 55, and 65 °C. The sample of yellow efflorescence mainly consisted of Na-jarosite, the white efflorescence contained melanterite as the major mineral, and the blue efflorescence sample consisted of chalcanthite. These all contained a few impurities up to 5 %. The highest total dissolved solids (TDS) was found in the gas condensates from melanterite (59 mg/L), followed by chalcanthite (29 mg/L) and Na-jarosite (17 mg/L). It was determined that major and trace elements in the condensate can be trapped by water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. X-ray diffractograms showed that Na-jarosite remained stable throughout the temperature range, whilst the separation of melanterite’s structural water occurred at 40 °C, and chalcanthite completely lost two water molecules at 50 °C. The gas condensates contained acetates and formates, which could be the fermentation products of bacterial communities. Some of the strains—Micrococcaceae sp., Bacillus sp., and Microbacteriaceae sp.—were cultivated.

MICROSTRUCTURE AND ELECTROCHEMICAL PROPERTIES OF Ni–B/GO ULTRASONIC-ASSISTED COMPOSITE COATINGS

2019 ◽  
Vol 26 (10) ◽  
pp. 1950080
Author(s):  
JIBO JIANG ◽  
HAOTIAN CHEN ◽  
LIYING ZHU ◽  
YAOXIN SUN ◽  
WEI QIAN ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Ultrasonic Field ◽  
Protective Material ◽  
X Ray ◽  
Electrochemical Tests ◽  
Ultrasonic Assisted ◽  
Corrosive Environments

Graphene oxide (GO) sheet and ultrasonic field (UF) were successfully employed to produce Ni–B/GO and UF–Ni–B/GO composite coatings on Q235 mild steel by electroless plating. The composite coatings’ structure and surface morphology were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Results showed that GO was successfully co-deposited in the Ni–B alloy. Moreover, UF–Ni–B/GO composite coatings have smoother surface and thicker cross-section than others. The microhardness and corrosion resistance of the sample coatings were determined using Vickers hardness tests, Tafel electrochemical tests and electrochemical impedance measurements (EIS) in 3.5[Formula: see text]wt.% NaCl solution to receive the effect of GO and ultrasonic. The findings indicated that UF–Ni–B/GO exhibited optimum hardness (856[Formula: see text]HV) and enhanced corrosion resistance (6.38 [Formula: see text][Formula: see text] over the Ni–B and Ni–B/GO coatings. Due to these interesting properties of the coating, it could be used as a protective material in the automotive and aerospace industries for parts of machines that were manipulated in high temperature and corrosive environments.

Preparation of New Anti-Slip Flooring Coatings: Hydrophobic MMA Floor Coatings

2013 ◽  
Vol 721 ◽  
pp. 73-76
Author(s):  
Shu Le Lin ◽  
Hui Hua Cai
Keyword(s):  
Electronic Spectroscopy ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Coating Properties ◽  
Hydrophobic Properties ◽  
X Ray ◽  
H Nmr ◽  
Potential Applications ◽  
Ft Ir ◽  
First Time

For the first time, hydrophobic MMA floor coatings were prepared based on the fluorine-containing methacrylic ester copolymers and applied as a new kind of anti-slip flooring coatings. The composition of the synthesized copolymers was characterized by FT-IR and 1H-NMR. The prepared hydrophobic MMA floor coatings were analyzed for their coating properties. The hydrophobic properties of the coatings were characterized by static and dynamic contact angles and X-ray photo-electronic spectroscopy (XPS). Results show that the newly prepared floor coatings are easy to apply and have excellent mechanical and hydrophobic properties, which indicates that the hydrophobic MMA floor coatings have great potential applications in anti-slip flooring coatings.

Electrochemical Properties of Li0.99Gd0.01FePO4/C Composite Cathode for Lithium-Ion Batteries

2010 ◽  
Vol 146-147 ◽  
pp. 1233-1237
Author(s):  
Bin Sun ◽  
Yi Feng Chen ◽  
Kai Xiong Xiang ◽  
Wen Qiang Gong ◽  
Han Chen
Keyword(s):  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Composite Cathode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Tests ◽  
Capacity Loss ◽  
Lattice Doping ◽  
Scanning Electron

Li0.99Gd0.01FePO4/C composite was prepared by solid-state reaction, using particle modification with amorphous carbon from the decomposition of glucose and lattice doping with supervalent cation Gd3+. All samples were characterized by X-ray diffraction, scanning electron microscopy, multi-point Brunauer Emmett and Teller methods. The electrochemical tests show Li0.99Gd 0.01FePO4/C composite obtains the highest discharge specific capacity of 154 mAh.g-1 at C/10 rate and the best rate capability. Its specific capacity reaches 131 mAh.g-1 at 2 C rate. Its capacity loss is only 14.9 % when the rate varies from C/10 to 2 C.

Comparative study of corrosion and corrosion-wear behavior of TiN and CrN coatings on UNS S17400 stainless steel

2018 ◽  
Vol 36 (4) ◽  
pp. 403-412 ◽  
Author(s):  
Hossein Olia ◽  
Reza Ebrahimi-Kahrizsangi ◽  
Fakhreddin Ashrafizadeh ◽  
Iman Ebrahimzadeh
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Physical Vapor Deposition ◽  
Wear Behavior ◽  
Open Circuit ◽  
Corrosion Wear ◽  
Nacl Solution ◽  
Compact Structure ◽  
X Ray ◽  
Electrochemical Tests

AbstractPhysical vapor deposition (PVD) multilayered coatings with titanium nitride and chromium nitride top layers were deposited on UNS S17400 alloy in an attempt to improve the corrosion and corrosion-wear resistance of this stainless steel in corrosive environments. The coatings were produced in an industrial chamber by cathodic arc PVD on heat-treated and mechanically polished stainless steel specimens. The microstructures of the substrates and coatings were characterized by X-ray diffraction and scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy system. To evaluate the corrosion and corrosion-wear resistance, reciprocating-sliding tribometer and electrochemical tests were conducted in 3.5% NaCl solution. The results showed that nitride coatings possess, in general, better corrosion and corrosion-wear resistance compared with bare S17400 substrates. Specimens with CrN top coating revealed a typical compact structure and superior corrosion resistance compared with substrate and TiN top coating. However, the sliding motion damaged the surface with some microcracks on the coating, which act as the diffusion channels for NaCl solution; both TiN and CrN top coats experienced approximately similar behavior in corrosion-wear open-circuit potential testing.

scholarly journals Enhanced Electrochemical Performances of Cobalt-Doped Li2MoO3 Cathode Materials

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 843 ◽  
Author(s):  
Zhiyong Yu ◽  
Jishen Hao ◽  
Wenji Li ◽  
Hanxing Liu
Keyword(s):  
Cathode Materials ◽  
Photoelectron Spectroscopy ◽  
Solid Phase ◽  
Phase Method ◽  
Electrochemical Performances ◽  
X Ray ◽  
Electrochemical Tests ◽  
Co Doping ◽  
Solid Phase Method ◽  
Better Than

Co-doped Li2MoO3 was successfully synthesized via a solid phase method. The impacts of Co-doping on Li2MoO3 have been analyzed by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) measurements. The results show that an appropriate amount of Co ions can be introduced into the Li2MoO3 lattices, and they can reduce the particle sizes of the cathode materials. Electrochemical tests reveal that Co-doping can significantly improve the electrochemical performances of the Li2MoO3 materials. Li2Mo0.90Co0.10O3 presents a first-discharge capacity of 220 mAh·g−1, with a capacity retention of 63.6% after 50 cycles at 5 mA·g−1, which is much better than the pristine samples (181 mAh·g−1, 47.5%). The enhanced electrochemical performances could be due to the enhancement of the structural stability, and the reduction in impedance, due to the Co-doping.

scholarly journals Effects of Mo Concentration on the Structural and Corrosion Properties of Cu–Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1307
Author(s):  
Oscar Hernández ◽  
Claudio Aguilar ◽  
Ariosto Medina
Keyword(s):  
Mechanical Alloying ◽  
Load Transfer ◽  
High Energy ◽  
Corrosion Properties ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Electrochemical Tests ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Electron Microscopy Analysis

Mechanical Alloying (MA) has the ability to extend the solubility limits of immiscible alloys in a solid state. In this work, a Cu-10 wt% Mo alloy was synthesized by mechanical alloying, using a high-energy mill type SPEX. The X-ray diffraction and Rietveld results show a crystallite size of 24 and 22 nm of Cu and Mo, respectively, with an occupation value of Mo inside the Cu structure of 27%, which was identificated by Energy Dispersive X-ray Spectroscopy and High-Resolution Transmission Electron Microscopy analysis. After that, the alloy was sinterized in an oven, heating the alloy to 1000 °C—close to the melting point of Cu (1085 °C). Electrochemical tests were carried out under a saline environment of synthetic seawater. The results show that the polarization curve of the alloy showed a pitting corrosion at about 134.83 mV, as well as a repasivation phenomenon (Erp = 241.47 mV) in the cathodic branch. Finally, three time constants were observed in the Nyquist diagrams: formation of a corrosion product film, load transfer, and diffusion, indicating that the corrosion properties in this alloy were improved compared with other Cu–alloys.

Various Types of Pt-Ni Binary Catalysts Supported on the Carbon Nanotubes as Cathode Catalysts for DMFC

2007 ◽  
Vol 119 ◽  
pp. 247-250 ◽  
Author(s):  
Yon Ki Seo ◽  
Yong Hwan Kim ◽  
Uoo Chang Chung ◽  
Won Sub Chung
Keyword(s):  
Carbon Nanotubes ◽  
Diffraction Pattern ◽  
Xrd Analysis ◽  
Metal Catalysts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Tests ◽  
Cathode Catalysts ◽  
Ni Alloy ◽  
Binary Catalysts

Several methods for loading of Pt-Ni binary catalysts on the CNTs were tested. Using the CNTs treated HNO3, the catalysts supported Pt, Ni separately(Pt&Ni/CNT) and Pt-Ni alloy(Pt- Ni/CNTs) were made respectively. The results of supporting were confirmed by TEM and XRD analysis. TEM images show that metal catalysts were loaded uniformly and finely on the CNTs. By XRD analysis, the peaks of Pt&Ni/CNTs displayed Pt and Ni peaks respectively. Also it was found that the peaks of Pt were shifted to the higher 2theta angle in X-ray diffraction pattern which indicated that Pt-Ni alloy was formed successfully(Pt-Ni/CNTs). In addition, electrochemical tests for cathode catalysts of DMFC were performed. As the results, Pt-Ni/CNTs was most suitable for cathode catalysts of DMFC.

Study on Properties of Zn-Al-Mg-RE Coatings by Arc Spraying

2013 ◽  
Vol 804 ◽  
pp. 79-84
Author(s):  
Fei Lu ◽  
Zhao Qian Xie ◽  
Yu Feng Lu ◽  
Miao Lou ◽  
Meng Zhou ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Arc Spraying ◽  
Long Term Effects ◽  
Electrochemical Protection ◽  
X Ray ◽  
Electrochemical Tests ◽  
Excellent Corrosion Resistance ◽  
Corrosion Reaction ◽  
High Velocity Arc Spraying

In order to improve the organization, reduce the porosity, compact the structure and enhance the corrosion resistance of the coating, Zn-Al-Mg-RE coating system was prepared by high velocity arc spraying. The surface appears, phase composition and electrochemical properties of the coating were characterized by scanning electron microscope, X-ray radiation diffaction and electrochemical workstation. The results indicated that the coatings were compact. The coatings were mainly zinc and aluminum phase. In corrosion of immersion, the reaction resistance and coating resistance of coatings quickly become bigger, the surface of coatings become more compact, and the corrosion reaction is more difficult. Electrochemical tests showed that the coating had excellent corrosion resistance. The electrochemical protection and self-sealing effect of coatings can have long-term effects on anticorrosion.

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