scholarly journals Microstructures and Metallographic Characterization of Superalloys

2019 ◽  
Vol 6 ◽  
Author(s):  
Patrice Berthod
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Chemical Properties ◽  
Metallic Alloys ◽  
Industrial Scale ◽  
Chemical Compositions ◽  
Electronic Microscopy ◽  
Different Types ◽  
And Chemical Properties

Superalloys are metallic alloys with specific microstructures and atoms in solid solution allowing good mechanical and chemical properties at high temperature, typically higher than 1000°C. They present many different types of {matrix – precipitates} combinations which can be characterized at each step of their elaboration, by specifying the chemical compositions and the crystalline network of the phases present. After test on a sample (laboratory scale), or after the deterioration in service of a component leading to its replacement by a new one (industrial scale), the superalloys constituting these pieces are often usefully examined. This aims to specify the changes occurred in their microstructures as well as in their surface or sub-surface, due to the endured thermal, mechanical and chemical solicitations. These characterizations can be simply done using basic low-magnification optical microscopic examinations. Other means such as electronic microscopy and other advanced apparatus may be usefully involved for further investigations. After a brief history about superalloys, an overview of the phenomenological aspects of their mechanical and chemical solicitations during their use at high temperature, the metallographic techniques which are usually employed to characterize them are presented and illustrated in the case of a chosen family of superalloys.

Characterization of Shivirtui Zeolite Modified with Aluminum Oxyhydroxide Nanofibers

2019 ◽  
Vol 942 ◽  
pp. 40-49
Author(s):  
Yulia Murashkina ◽  
Olga B. Nazarenko
Keyword(s):  
Chemical Properties ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
X Ray ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Aluminum Oxyhydroxide

Natural zeolite of Shivirtui deposit (Russia) was modified with nanofibers of aluminum oxyhydroxide AlOOH. Aluminum oxyhydroxide nanofibers were produced at the heating and oxidation of aluminum powder with water. The properties of modified zeolite were investigated by means of X-ray diffraction, transmission electronic microscopy, scanning electronic microscopy, low-temperature nitrogen adsorption, thermal analysis, and Fourier transform infrared spectroscopy. It was found that water content in the modified sample of zeolite was about 15 %. Based on the study of the physical and chemical properties, shivirtui zeolite modified with nanofibers of aluminum oxyhydroxide can be proposed for use as a flame-retardant additive to polymers.

scholarly journals Preparation and Characterization of Sulfonated Carbon Cryogel Doped Zinc as a Catalyst for Glucose Ethanolysis to Ethyl Levulinate

2021 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
Muzakkir Mohammad Zainol ◽  
Mohamad Nor Fitri Roslan ◽  
Mohd Asmadi ◽  
Nor Aishah Saidina Amin
Keyword(s):  
Chemical Properties ◽  
Catalyst Loading ◽  
Solid Catalyst ◽  
Ethyl Levulinate ◽  
Different Types ◽  
Carbon Cryogel ◽  
Physical And Chemical ◽  
Catalytic Effects ◽  
And Chemical Properties

In this study, sulfonated carbon cryogel (CC) doped with zinc was prepared and used as a solid catalyst. Carbon cryogel was prepared by mixing urea and furfural, freeze-drying, and calcination. The CC was then sulfonated and impregnated with zinc (II) nitrate for ethyl levulinate production from ethanolysis of glucose. Experiment results showed that different types of catalyst prepared from CC precursor had different catalytic effects on the ethanolysis of glucose. Sulfonated carbon cryogel doped with zinc (SCC-Zn) which prepared at a calcination temperature of 300 °C showed better performance as a catalyst for the ethanolysis reaction of glucose. In addition, the 10 wt.% of Zn was recommended as optimum loading for the impregnation on the catalyst. The ethyl levulinate yield of 19.6 mol% was obtained at 180 °C for 6 h with 0.15 g catalyst loading and 0.4 g of glucose feed. The selected SCC-Zn catalyst was further characterized by using FTIR, TGA XRD, and SEM-EDX to evaluate its physical and chemical properties as a catalyst.

Vulcanization and Vulcanizate Properties of a Fluoroelastomer Containing Epoxy Groups as Cure Sites

1981 ◽  
Vol 54 (4) ◽  
pp. 779-796 ◽  
Author(s):  
G. Kojima ◽  
H. Kojima ◽  
M. Morozumi ◽  
H. Wachi ◽  
M. Hlsasue
Keyword(s):  
High Temperature ◽  
Vinyl Ether ◽  
Room Temperature ◽  
Chemical Properties ◽  
Complex Shapes ◽  
Different Types ◽  
Hostile Environments ◽  
Epoxy Groups ◽  
And Chemical Properties ◽  
Glycidyl Vinyl Ether

Abstract The vulcanization behavior and vulcanizate properties of tetrafluoroethylene-propylene elastomer containing a small amount of glycidyl vinyl ether as cure site was investigated both at room temperature and at high temperature with different types of the vulcanizing agents. The conclusions are: 1. Glycidyl vinyl ether incorporates into the tetrafluoroethylene-propylene copolymerization system without disturbing the alternating microstructure and works as an efficient cure site. 2. The room-temperature vulcanization of the terpolymer proceeds at an adequate rate when tris(dimethylaminomethyl)phenol is used as the curative together with phenol as the accelerating agent. 3. Coatings of the terpolymer make a tough finish on many substrates such as steel and hydrocarbon rubbers and protect the substrates from hostile environments. 4. The vulcanization behavior of the terpolymer at high temperature is much influenced by the kind of curative. The carboxylate of hexamethylenediamine [e.g., hexamethylenediamine-N,N′-bis(p-isopropylbenzoate)] provides balanced vulcanization behavior and mechanical properties suitable for molding articles of complex shapes. 5. The mechanical and chemical properties of the high-temperature vulcanizate thus obtained are similar to those of the tetrafluoroethylene-propylene binary system vulcanized by peroxide.

Preparation and Characterization of Nanostructured FeS2 and CoS2 for High-Temperature Batteries

2002 ◽  
Vol 730 ◽  
Author(s):  
Ronald A. Guidotti ◽  
Frederick W. Reinhardt ◽  
Jinxiang Dai ◽  
David E. Reisner
Keyword(s):  
High Temperature ◽  
Single Cells ◽  
Scale Up ◽  
Chemical Properties ◽  
Plant Size ◽  
Physical And Chemical Properties ◽  
Commercial Source ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractIn this paper, we report on the preparation of synthetic FeS2 and CoS2 using a relatively inexpensive aqueous process. This avoids the material and handling difficulties associated with a high-temperature approach. An aqueous approach also allows ready scale-up to a pilot-plant size facility. The FeS2 and CoS2 were characterized with respect to their physical and chemical properties. The synthetic disulfides were incorporated into catholyte mixes for testing in single cells and batteries over a range of temperatures. The results of these tests are presented and compared to the performance of natural FeS2 (pyrite) and a commercial source of CoS2.

scholarly journals Mineralogical and chemical properties inversed from 21-lunar-day VNIS observations taken during the Chang’E-4 mission

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qinghong Zeng ◽  
Shengbo Chen ◽  
Yuanzhi Zhang ◽  
Yongling Mu ◽  
Rui Dai ◽  
...  
Keyword(s):  
Impact Crater ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Chemical Properties ◽  
Landing Site ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Chemical Compositions ◽  
Impact Melt ◽  
And Chemical Properties

AbstractWe report on the mineralogical and chemical properties of materials investigated by the lunar rover Yutu-2, which landed on the Von Kármán crater in the pre-Nectarian South Pole–Aitken (SPA) basin. Yutu-2 carried several scientific payloads, including the Visible and Near-infrared Imaging Spectrometer (VNIS), which is used for mineral identification, offering insights into lunar evolution. We used 86 valid VNIS data for 21 lunar days, with mineral abundance obtained using the Hapke radiative transfer model and sparse unmixing algorithm and chemical compositions empirically estimated. The mineralogical properties of the materials at the Chang’E-4 (CE-4) site referred to as norite/gabbro, based on findings of mineral abundance, indicate that they may be SPA impact melt components excavated by a surrounding impact crater. We find that CE-4 materials are dominated by plagioclase and pyroxene and feature little olivine, with 50 of 86 observations showing higher LCP than HCP in pyroxene. In view of the effects of space weathering, olivine content may be underestimated, with FeO and TiO2 content estimated using the maturity-corrected method. Estimates of chemical content are 7.42–18.82 wt% FeO and 1.48–2.1 wt% TiO2, with a low-medium Mg number (Mg # ~ 55). Olivine-rich materials are not present at the CE-4 landing site, based on the low-medium Mg #. Multi-origin materials at the CE-4 landing site were analyzed with regard to concentrations of FeO and TiO2 content, supporting our conclusion that the materials at CE-4 do not have a single source but rather are likely a mixture of SPA impact melt components excavated by surrounding impact crater and volcanic product ejecta.

The Extraction of Main Chemical Compositions in Rumex Root

2011 ◽  
Vol 382 ◽  
pp. 372-374
Author(s):  
Yong Jiang ◽  
Zhi Bin Jiang ◽  
Guo Jie Shao ◽  
Dong Cheng Guo ◽  
Yu Tian ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Chemical Properties ◽  
Ethanol Extract ◽  
Chemical Compositions ◽  
Physical And Chemical Properties ◽  
Experimental Basis ◽  
Development And Utilization ◽  
Physical And Chemical ◽  
Root Methods ◽  
And Chemical Properties

Purpose: The purpose of this study was to study the compositions of the polygonaceae medicinal plants called rumex root. Methods: Solvent method and chromatography was used to purificate the chemical compositions of Rumex, and the molecular structure of the compound was identified by physical and chemical properties and spectral data. Results: Two compounds were obtained from the ethanol extract of rumex root, which were identified as Chrysophanol and Physcione. Conclusions: Experimental basis was provided for the further study of the active ingredients of rumex root and the development and utilization of medical resources.

Influence of Regeneration Condition on Physical and Chemical Properties of High Temperature Coal Gas Desulfurization Sorbent

2014 ◽  
Vol 521 ◽  
pp. 658-661
Author(s):  
Lei Yang ◽  
Shang Guan Ju ◽  
Yu Kun Gao ◽  
Yan Hui Hu
Keyword(s):  
High Temperature ◽  
Circulatory System ◽  
Chemical Properties ◽  
Space Velocity ◽  
Physical And Chemical Properties ◽  
Coal Gas ◽  
Regeneration Condition ◽  
Atmosphere Temperature ◽  
Physical And Chemical ◽  
And Chemical Properties

Physical and chemical properties are closely related to desulfurization, regeneration performance and cycle stability for high temperature coal gas desulfurizer. This review focuses on influence rules of changes in regeneration atmosphere, temperature and space velocity on physical and chemical properties. A large number of experimental researches have shown that regeneration atmosphere, regeneration temperature, space velocity have an important influence on mechanical strength, active component and texture change for high temperature coal gas desulfurizer. The different regeneration atmosphere obviously results in different active ingredients for desulfurization sorbent after regeneration, and regeneration at a higher regeneration temperature will easily cause desulfurizer sintering, as well as small regeneration space velocity can lead to the formation of sulfates. In order to make the circulatory system of sulfidation-regeneration-sulfidation need to the requirements in industrial application, the further research of influence rules of regeneration condition on physical and chemical properties will be crucial.

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