Potentiometric NO2 Sensor Based on YSZ and WS2

In this study, Yttria-stabilized zirconia (YSZ) electrochemical sensors attached with the WS2 sensing electrode (SE) were fabricated and examined for NO2 sensing properties. Due to its internal stratiform structure, surface and edge of the lamella have high chemical activity, WS2 was used as a kind of highly efficient catalyst. WS2 was partial oxidated to WO3 at 400°C, and with the increment of temperature, oxidation will accelerate. The ΔEMF to 500 ppm NO2 was as high as 125mv at 400°C, while the value of WO3-based sensor was as small as 10 mv in the same condition. These WS2-attached devices gave a linear correlation between EMF and the logarithm of NO2 concentration from 30 to 500 ppm in the temperature range 350–500°C. The response time of the device is about 1 min at 400°C.

Download Full-text

Substrate Influence in YBaCuO Melt-Texturing Growth

MRS Proceedings ◽

10.1557/proc-275-537 ◽

1992 ◽

Vol 275 ◽

Cited By ~ 1

Author(s):

N. Pellerin ◽

M. Gervais ◽

P. Odier

Keyword(s):

Chemical Activity ◽

High Chemical ◽

Melt Texturing ◽

Substrate Influence ◽

High Chemical Activity

Melt-texturing of YBaCuO is generally processed on substrates. Due to its high chemical activity, the non-stoichiometric liquid, mainly due to the barium element, generally reacts with the substrate which is therefore subjected to play a role in the crystallization of YBaCuO and in the development of the texture. The particular case of Y2O3, which is a reacting but non-polluting substrate, is treated in details. The comparison of textured YBaCuO in similar conditions but on different substrates: Al2O3, Y2O3 and MgO gives some insight in the texturing process.

Download Full-text

Electrochemical and Oxidation Behavior of Yttria Stabilized Zirconia Coating on Zircaloy-4 Synthesized via Sol-Gel Process

International Journal of Corrosion ◽

10.1155/2013/453835 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

S. Rezaee ◽

Gh. R. Rashed ◽

M. A. Golozar

Keyword(s):

Heat Treatment ◽

Electrochemical Impedance ◽

Sol Gel ◽

Dip Coating ◽

Open Circuit ◽

Treatment Temperature ◽

Yttria Stabilized Zirconia ◽

Coated Sample ◽

Stabilized Zirconia ◽

Temperature Oxidation

Sol-gel 8 wt.% Yttria Stabilized Zirconia (YSZ) thin films were prepared on zirconium (zircaloy-4 alloy) by dip-coating technique followed by heat treating at various temperatures (200°C, 400°C, and 700°C) in order to improve both electrochemical corrosion and high temperature oxidation properties of the substrate. Differential thermal analysis and thermogravimetric analysis (DTA-TG) revealed the coating formation process. X-ray diffraction (XRD) was used to determine the crystalline phase structure transformation. The morphological characterization of the coatings was carried out using scanning electron microscopy (SEM). The electrochemical behavior of the coated and uncoated samples was investigated by means of open circuit potential, Tafel, and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. The homogeneity and surface appearance of coatings produced was affected by the heat treatment temperature. According to the corrosion parameters, the YSZ coatings showed a considerable increase in the corrosion resistance, especially at higher heat treatment temperatures. The coating with the best quality, from the surface and corrosion point of view, was subjected to oxidation test in air at 800°C. The coated sample presented a 25% reduction in oxidation rate in comparison with bare substrate.

Download Full-text

The use of 19F in Medicine in Poland and in the World

Biointerface Research in Applied Chemistry ◽

10.33263/briac126.85618572 ◽

2021 ◽

Vol 12 (6) ◽

pp. 8561-8572

Keyword(s):

Chemical Element ◽

Chemical Activity ◽

Toxic Effects ◽

Large Impact ◽

High Chemical ◽

High Affinity ◽

The World ◽

Living Organisms ◽

Very High ◽

High Chemical Activity

Fluorine is a chemical element belonging to the group of halogens. Due to its many properties, it has been used in various fields of medicine, mainly in dentistry, pharmacology, oncology, and radiology. It is an element that occurs naturally in the environment with a very high chemical activity. In addition, it has a high affinity for calcium or magnesium [1], which may have a large impact on the body's functioning when a higher dose of fluoride is taken. Moreover, fluorine is an element that has toxic effects, not only on living organisms but also on the environment. Fluoride-based preparations are widely used in several areas of medicine. This paper presents the use of fluoride in its various branches of medicine.

Download Full-text

Carbon as an Effective Modifier of Silicon Dioxide and Reagent for Obtaining Nanostructurized SHS-Composites

Eurasian Chemico-Technological Journal ◽

10.18321/ectj96 ◽

2011 ◽

Vol 14 (1) ◽

pp. 31

Author(s):

Z.A. Mansurov ◽

N.N. Mofa

Keyword(s):

Silicon Dioxide ◽

Chemical Activity ◽

Powder Materials ◽

Redox Processes ◽

Nanosized Particles ◽

High Chemical ◽

Structure And Morphology ◽

Composition Materials ◽

Composition Structure ◽

High Chemical Activity

The peculiarities of the structure and morphology of quartz particles modified by carbon depending on MCT conditions and type of specific carbonaceous modifier were studied. Powder materials with the composition structure of the materials, which are hybrid formations organics-inorganics with a high chemical activity of its components, were obtained by combined MCT of carbon or carbon containing organic compounds with quartz. A high chemical activity of quartz particles modified by carbon is effectively realized when producing SHS-ceramics composition materials. The rate of redox processes increases, the initial reagents are most completely realized and nanosized particles of silicon carbide are formed. It is shown how one can regulate the process of combustion in SH-synthesis and produce the material of the necessary quality by modifying silicon dioxide particles in the course of MCT.

Download Full-text

A second species of the genus Thermochiton Saito et Okutani, 1990 (Mollusca: Polyplacophora)

Ruthenica, Russian Malacological Journal ◽

10.35885/ruthenica.2021.30(1).2 ◽

2020 ◽

Vol 30 (1) ◽

pp. 7-12

Author(s):

B. I. Sirenko

Keyword(s):

New Species ◽

Papua New Guinea ◽

New Guinea ◽

Chemical Activity ◽

High Chemical ◽

Deep Waters ◽

A New Species ◽

High Chemical Activity

The paper describes a new species of the genus , sp. nov., found in deep waters off Papua New Guinea. This species differs from primarily in the dorsal scales, the marginal spicules, sculpture of the jugal area and the shape of the central teeth of radula. There are apparent similarities between the species of the genus Thermochiton , Connexochiton platynomenus , C. kaasi and Ischnochiton crassus. The last species is proposed to be transferred to . Owing to the friable, rusty brown deposits that densely cover the shell and girdle of both specimens of , the latter probably lives in areas of high chemical activity.

Download Full-text

Rapid Growth of Tin Whiskers on the Surface of Sn3.8Ag0.7Cu1.0Y Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.557-559.1397 ◽

2012 ◽

Vol 557-559 ◽

pp. 1397-1403

Author(s):

Jun Tian ◽

Hu Hao

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Rapid Growth ◽

Trace Amount ◽

Volume Expansion ◽

Solder Matrix ◽

Chemical Activity ◽

Tin Whiskers ◽

High Chemical ◽

High Chemical Activity

It is known that rare-earth elements exhibit high chemical activity and adding trace amount of rare-earth Y in the solder can significantly improve the properties of solder alloy. However, adding excessive rare-earth Y in the solder will result in rapid growth of tin whiskers. The research results show that: if the YSn3 precipitates formed in the interior of Sn3.8Ag0.7Cu1.0Y were exposed to the air, YSn3 precipitates will oxidize and expand in volume, and the tremendous compressive stress produced by the surrounding solder matrix constraining the volume expansion will accelerate the growth of tin whiskers.

Download Full-text