Improvement of the Oxidation Behavior of Yb-Gd-Si Ternary Alloys at Low Temperatures via Ti Addition

2021 ◽  
Author(s):  
Yutaro Arai ◽  
Hiroki Morigayama ◽  
Takuya Aoki ◽  
Ryo Inoue
Keyword(s):  
Thermogravimetric Analysis ◽  
Low Temperatures ◽  
Oxidation Rate ◽  
Oxidation Behavior ◽  
Ternary Alloys ◽  
Temperature Range ◽  
Arc Melting ◽  
Ti Addition ◽  
O Phase ◽  
Oxidation Behaviors

Abstract To improve the oxidation behavior of Yb-Gd-Si, 0.5 and 1 at% of Ti-containing Yb-Gd-Si (denoted as YGTS-0.5 and YGTS-1, respectively) were fabricated by arc melting. The oxidation behaviors of both YGTS specimens were evaluated by oxidation tests performed in a temperature range of 600–1200 °C for 1, 2, 4, and 8 h in air. Additionally, thermogravimetric analysis (TGA) was conducted at the abovementioned temperature range in air and steam. Oxidation tests at 1200 °C revealed no significant changes in the oxidation rate. Moreover, the oxidation tests revealed that Yb-Gd-Si and YGTS-0.5 became powdery after oxidation, whereas YGTS-1 maintained its form. Detailed microstructural observations indicated that the formation of TiO2 and other oxides in the Yb-Ti-O phase and oxide-containing Yb, Gd, Ti, and Si suppressed the formation of Yb2O3, which caused drastic oxidation at intermediate temperatures (600–900 °C). These results indicated that the addition of 1 at% of Ti to Yb-Gd-Si was effective in improving its oxidation behavior.

Oxidation Behaviors of Inconel 740H in Air and Dynamic Steam

2016 ◽  
Vol 35 (7) ◽  
pp. 697-704
Author(s):  
Jintao Lu ◽  
Zhen Yang ◽  
Songqian Xu ◽  
Haiping Zhao ◽  
Y. Gu
Keyword(s):  
Surface Roughness ◽  
Oxidation Product ◽  
Oxidation Rate ◽  
Power Plants ◽  
Oxidation Behavior ◽  
Test Environment ◽  
Parabolic Law ◽  
Oxide Particles ◽  
Pure Steam ◽  
Oxidation Behaviors

AbstractInconel 740H alloy is a candidate material for 700°C advanced ultra-supercritical (A-USC) coal-fired power plants application as superheater/reheater tube. In this work, oxidation behavior of Inconel 740H alloy was studied in static air at 750°C and 850°C, and in dynamic pure steam at 750°C, respectively. The alloy was oxidized approximately following a parabolic law in three test environment. In the static air, the oxidation rate at 850°C was about 50 times of that at the 750°C. More NiCrMn spinal and TiO2 were detected after oxidation at 850°C. Cr2O3, however, was the main oxidation product at 750°C. In the pure steam, Cr2O3 was still the main oxidation product. The oxidation rate was about 2.6 times of that in static air, but the surface roughness was much smaller and edges of oxide particles were more blurred. There was no evidence of cracks or spallation in three test environments.

Oxidation of Pure Solid CaS with Ar-O2 Gas Mixture

2012 ◽  
Vol 31 (4-5) ◽  
pp. 667-673 ◽  
Author(s):  
K. Kobayashi ◽  
T. Hiraki ◽  
T. Nagasakaki
Keyword(s):  
Weight Gain ◽  
Oxidation Rate ◽  
Oxidation Behavior ◽  
Sulfur Removal ◽  
Gas Mixture ◽  
Temperature Range ◽  
Maximum Value ◽  
Lower Temperature Range ◽  
Lower Temperature ◽  
Sulfur Containing

SynopsisOxidation behavior of CaS in oxidizing atmosphere has been investigated for the regeneration process of desulfurization slag by oxidation. The temperature range of oxidation of CaS reagent with Ar-21%O2 gas was 973 to 1423 K. The weight gain was observed in the lower temperature range and reached at the maximum value at 1173 K while weight gain turned to decrease when the reaction temperature was higher than 1173 K. It was clarified that CaS was oxidized to CaSO4 under 1173 K or to CaO over 1373 K by the measurement of oxidation rate, XRD and thermodynamic analysis. The results strongly suggested that sulfur removal from the sulfur containing slag may be possible at temperatures of 1223 K or higher by the oxidation of with air.

Oxidation Behavior of Fe-15Cu-10Al Ternary Alloys at 700°C

2014 ◽  
Vol 598 ◽  
pp. 51-54
Author(s):  
Jun Huai Xiang ◽  
Xian Chao Xu ◽  
Wei Wang
Keyword(s):  
Binary Alloy ◽  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Oxidation Behavior ◽  
Ternary Alloys ◽  
External Layer ◽  
Alumina Layer ◽  
Al Content ◽  
Beneficial Role ◽  
Kinetics Of

The oxidation behavior of Fe-15Cu-10Al alloy was investigated at 700°C. Oxidation kinetics of the alloy conformed nearly to the parabolic rate law. The scales were composed mainly of alumina, plus a few nodules rich in iron. The very low oxidation rate of Fe-15Cu-10Al alloy showed that 10at.% Al level reached the critical Al content to form a complete Al2O3external layer. Compared with the corresponding Fe-10Al binary alloy, the addition of 15at.% Cu played a beneficial role for the establishment of the full protective alumina layer.

Oxidation Behavior of a Disk Powder Metallurgy Superalloy

2017 ◽  
Vol 898 ◽  
pp. 467-475
Author(s):  
Kai Xin Dong ◽  
Chao Yuan ◽  
Shuang Gao ◽  
Jian Ting Guo
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Spray Forming ◽  
X Ray Diffraction ◽  
Temperature Range ◽  
Scale Thickness ◽  
Aluminum Ions ◽  
Gain Measurement ◽  
Oxidation Behaviors

Oxidation behaviors of a spray-forming disk superalloy LSHR were investigated in the temperature range of 750-900°C. The composition and morphology of oxidation scales were investigated by X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and electron probe microanalysis (EPMA). Oxidation kinetics was studied by the means of isothermal oxidation testing in air and weight gain measurement. The oxide scales were composed of Cr2O3, TiO2, Al2O3 and a small amount of NiCr2O4. The experiment results showed that oxidation kinetics and oxide layers followed a square power law as time extended from 750 to 900°C. With the oxidation temperature increasing, external scale thickness, and internal oxidation zone increased. The oxidation behavior was controlled by the diffusion of oxygen, chromium, titanium, and aluminum ions, as chromium, titanium, and aluminum ions diffused outward and oxygen diffused inward. Based on the standard HB5258-2000 spray-forming LSHR exhibited an excellent oxidation resistance in the whole test temperature range.

On the Oxidation Behaviors of MoSi2 at 673 – 873 K

2011 ◽  
Vol 284-286 ◽  
pp. 1630-1634 ◽  
Author(s):  
Hou An Zhang ◽  
Si Yong Gu
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Rate ◽  
Oxidation Reaction ◽  
Oxidation Behavior ◽  
Kinetics Model ◽  
Thermodynamics And Kinetics ◽  
Reaction Constant ◽  
Oxidation Behaviors

On the basis of analysis of thermodynamics and kinetics on the oxidation behavior of MoSi2at 673 – 873 K, an oxidation kinetics model is established. The kinetics model gives a well explanation that the very severe oxidation rate of MoSi2at 773 K is because of the maximum oxidation reaction constant near this temperature.

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

Dynamic Viscosity of Compressed Water to 10 Kilobar and Steam to 1500°C

1969 ◽  
Vol 11 (2) ◽  
pp. 189-205 ◽  
Author(s):  
E. A. Bruges ◽  
M. R. Gibson
Keyword(s):  
Gaseous Phase ◽  
Dynamic Viscosity ◽  
Low Temperatures ◽  
Pressure Range ◽  
Low Pressure ◽  
Temperature Range ◽  
Inversion Temperature ◽  
Pressure Steam ◽  
Correlating Equations ◽  
First Time

Equations specifying the dynamic viscosity of compressed water and steam are presented. In the temperature range 0-100cC the location of the inversion locus (mu) is defined for the first time with some precision. The low pressure steam results are re-correlated and a higher inversion temperature is indicated than that previously accepted. From 100 to 600°C values of viscosity are derived up to 3·5 kilobar and between 600 and 1500°C up to 1 kilobar. All the original observations in the gaseous phase have been corrected to a consistent set of densities and deviation plots for all the new correlations are given. Although the equations give values within the tolerances of the International Skeleton Table it is clear that the range and tolerances of the latter could with some advantage be revised to give twice the existing temperature range and over 10 times the existing pressure range at low temperatures. A list of the observations used and their deviations from the correlating equations is available as a separate publication.

Optimization of Sample Holder Materials for Sensitive Magnetometry Measurements at Low Temperatures

2004 ◽  
Vol 825 ◽  
Author(s):  
I. Bossi ◽  
N.R. Dilley ◽  
J. R. O'Brien ◽  
S. Spagna
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
Magnetic Response ◽  
Sample Holder ◽  
Magnetization Measurements ◽  
Temperature Range ◽  
Paramagnetic Impurities ◽  
Fused Quartz

AbstractMagnetization measurements were performed as a function of magnetic field H and temperature T on samples of nine different materials including clear fused quartz, cartridge brass, G-10 glass-reinforced epoxy, acetal homopolymer, glass-filled acetal, phenolic, and other plastics. A small yet distinct amount of ferromagnetic or paramagnetic impurities is observed in all the materials investigated in this study except quartz. In contrast, the magnetic response of quartz is typical of a diamagnet over the temperature range 5 K to 300 K. The volume susceptibility is equal to −4.4×10−7 (cgs) over the whole temperature range.

High-Temperature Corrosion Performance of FeAl-Based Alloys Containing Carbon in Molten Salt

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2040
Author(s):  
Munish Kumar ◽  
Ravi Kant ◽  
Suresh Chand ◽  
Ujjwal Prakash ◽  
Shankar Sehgal ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Molten Salts ◽  
Corrosion Performance ◽  
X Ray Diffraction ◽  
Corrosive Media ◽  
Al2o3 Layer ◽  
X Ray ◽  
Aggressive Environment ◽  
Arc Melting ◽  
Ti Addition

Corrosion behavior of FeAl-based alloys containing carbon produced through arc melting in argon atmosphere has been studied at 500 °C to 700 °C. The samples were tested in the aggressive environment of molten salts (80%V2O5/20%Na2SO4). The corrosion behavior was observed by weight change method and the layer products formed were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The different phase components were observed in the surface layer after the test in Fe-22Al alloy. A protective Al2O3 layer was confirmed for Fe-22Al alloy containing carbon only. However, an additional TiO layer was also observed in Fe-22Al alloy containing carbon with Ti addition. The microstructural and XRD examinations revealed that this additional TiO layer protects better against penetration of corrosive media. The corrosion resistance behavior of FeAl-based alloys were addressed on the basis of microstructural evidence.

Oxidation Behavior of Amorphous Nano-Si3N4 Powders

2014 ◽  
Vol 602-603 ◽  
pp. 367-370 ◽  
Author(s):  
Jiang Bo Wen ◽  
Sheng Huang ◽  
Hong Jie Wang
Keyword(s):  
High Temperature ◽  
Partial Pressure ◽  
Mechanical Behavior ◽  
Low Temperatures ◽  
Traditional Method ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Composite Ceramic ◽  
Intergranular Phase ◽  
Sintering Additives

The traditional method preparing Si3N4/Si2N2O composite ceramic is to sinter α-Si3N4 powder with additives at relatively high temperatures. But the intergranular phase transformed from the sintering additives can degrade the high-temperature mechanical behavior. Amorphous nanoSi3N4 is used to fabricate Si3N4/Si2N2O composite ceramic by its oxidation and nitridation without sintering additives at low temperatures. Thus, it is essential to study the oxidation behavior and mechanism of amorphous nanoSi3N4. Amorphous nanoSi3N4 powders were oxidized in different atmospheres, at varying temperatures and for various different length of time. The oxidation process and products was analyzed by means of XRD, TGA and FTIR. The results showed that amorphous nanoSi3N4 could be oxidized into SiO2 from 600°C to 1300°C. Below 1300°C, the oxidation became serious as the temperature increased. Besides, the longer the oxidation time and the lager the ratio of O2/N2 partial pressure was, the deeper the oxidation level was. When the temperature was above 1300°C, amorphous nanoSi3N4 was completely oxidized into SiO2.

Sign in / Sign up

Export Citation Format

Share Document