Thermal stability of phases in a NiCoCrAlY coating alloy

2008 ◽  
Vol 23 (8) ◽  
pp. 2264-2274 ◽  
Author(s):  
J.J. Liang ◽  
H. Wei ◽  
G.C. Hou ◽  
Q. Zheng ◽  
X.F. Sun ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Temperature Dependence ◽  
Experimental Observation ◽  
Thermodynamic Modeling ◽  
Thermodynamic Data ◽  
Reasonable Agreement ◽  
Temperature Dependent ◽  
Thermal Stabilities ◽  
Thermal Stability Of ◽  
Coating Alloy

The temperature dependence of the thermal stability in a NiCoCrAlY coating alloy was examined by experimental observation and thermodynamic modeling in the 400–1200 °C temperature range. The results indicated that the thermal stabilities of primary β–NiAl, β–NiAl/α–Cr eutectic, and γ–Ni were slightly temperature dependent, but those of γ′–Ni3Al, σ–(Cr,Co,Ni), and α–Cr were strongly temperature dependent in the annealed NiCoCrAlY specimens. The temperature dependence of the thermal stabilities among γ′–Ni3Al, σ–(Cr,Co,Ni), and α–Cr might be ascribed to the σ → α transformation at ∼1100 °C and the γ′ → γ transformation at ∼800 °C. Further, using Thermocalc associated with TTNi7 database, thermodynamic equilibria were calculated. The modeling results were compared with the experimental results and found to be in reasonable agreement with the experimental observations of β–NiAl, σ–(Cr,Co,Ni), and γ′–Ni3Al. Some deviations observed are discussed in the light of both limited availability of thermodynamic data and experimental problems.

Syntheses, Crystal Structures and Thermal Stability of Co(II) and Zn(II) Complexes with Ethyl Carbazate

2005 ◽  
Vol 60 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Tong-Lai Zhang ◽  
Jiang-Chuang Song ◽  
Jian-Guo Zhang ◽  
Gui-Xia Ma ◽  
Kai-Bei Yu
Keyword(s):  
Thermal Stability ◽  
Aqueous Solutions ◽  
Diffraction Analysis ◽  
Single Crystals ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
Thermal Stabilities ◽  
X Ray ◽  
Thermal Stability Of

Cobalt(II) and zinc(II) complexes of ethyl carbazate (ECZ), [Co(ECZ)3](NO3)2 and [Zn(ECZ)3] (NO3)2, were synthesized. Single crystals of these two compounds were grown from aqueous solutions using a slow evaporation method. Their structures have been determined by X-ray diffraction analysis. Both of them are monoclinic with space group P21/n. The complexes are further characterized by element analysis and IR measurements. Their thermal stabilities are studied by using TG-DTG, DSC techniques. When heated to 350 °C, only metal oxide was left for both complexes.

Simulation of Thermal Stability and Friction: A Lubricant Confined Between Monolayers of Wear Inhibitors on Iron Oxide

1998 ◽  
Vol 543 ◽  
Author(s):  
T. Çağin ◽  
Y. Zhou ◽  
E. S. Yamaguchi ◽  
R. Frazier ◽  
A. Ho ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Thermal Stability ◽  
Quantum Chemical ◽  
Md Simulations ◽  
Atomic Level ◽  
The Self ◽  
Self Assembled Monolayer ◽  
Thermal Stabilities ◽  
Frictional Forces ◽  
Thermal Stability Of

AbstractTo understand antiwear phenomena in motor engines at the atomic level and provide evidence inselecting future ashless wear inhibitors, we studied the thermal stability of the self-assembled monolayer(SAM) model for dithiophosphate (DTP) and dithiocarbamate (DTC) molecules on the iron oxidesurface using molecular dynamics. The interactions for DTP, DTC and Fe2O3 are evaluated based on aforce field derived from fitting to ab initio quantum chemical calculations of dimethyl DTP (and DTC)and Fe(OH)2(H2O)2-DTP (DTC) clusters. MD simulations at constant-NPT are conducted to assesrelative thermal stabilities of the DTP and DTC with different pendant groups (n-propyl, i-propyl, npentyl.and i-pentyl). To investigate frictional process, we employ a steady state MD method, in whichone of the Fe2O3 slabs maintained at a constant linear velocity. We obtain the time averaged normaland frictional forces from the interatomic forces. Then, we calculated the friction coefficient at theinterface between SAMs of DTP and the confined lubricant, hexadecane, to assess the shear stability ofDTPs with different pendant groups.

scholarly journals Phase transition and thermal stability of epitaxial PtSe2 nanolayer on Pt(111)

RSC Advances ◽  
2020 ◽  
Vol 10 (51) ◽  
pp. 30934-30943 ◽  
Author(s):  
Yongfeng Tong ◽  
Meryem Bouaziz ◽  
Hamid Oughaddou ◽  
Hanna Enriquez ◽  
Karine Chaouchi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Chemical Deposition ◽  
Deposition Method ◽  
Temperature Dependent ◽  
Chemical Deposition Method ◽  
Thermal Stability Of

LEED, STM and XPS techniques were used to systematically study a temperature-dependent phase transition on a PtSe2 film grown on the surface of Pt(111) by a chemical deposition method.

Thermal Stability of GaAs/InGaP and InGaP/(In)GaAs Interfaces

1995 ◽  
Vol 405 ◽  
Author(s):  
F. Hyuga ◽  
T. Nittono ◽  
K. Watanabe ◽  
T. Furuta
Keyword(s):  
Thermal Stability ◽  
Quantum Wells ◽  
Annealing Time ◽  
High Performance ◽  
High Reliability ◽  
Half Maximum ◽  
Single Quantum ◽  
Thermal Stabilities ◽  
Temperature Range ◽  
Thermal Stability Of

AbstractThermal stabilities of GaAs/InGaP and InGaP/(In)GaAs interfaces are investigated using InGaP/(In)GaAs/InGaP single quantum wells. Annealing is performed at a temperature range between 600 and 900 °C for 10 min. Positions and the full widths at half maximum (FWHM) of photoluminescence (PL) peaks are almost identical to those of as-grown ones up to 800 °C. Blue shifts of PL peaks and increased widths of their FWHM observed after 900 °C annealing are suppressed by shortening the annealing time to 0.1 sec. Annealing at 900 ‘C for 0.1 sec is sufficient to activate Si ions implanted into (In)GaAs layers. As a result, these thermal stabilities are able to provide high reliability and high performance of InGaP/(In)GaAs heterostructure MESFET ICs.

Thermal stability of ribosomes from a psychrophilic and a mesophilic yeast

1969 ◽  
Vol 15 (9) ◽  
pp. 1116-1118 ◽  
Author(s):  
C. H. Nash ◽  
D. W. Grant
Keyword(s):  
Thermal Stability ◽  
Candida Utilis ◽  
Thermal Stabilities ◽  
Similar Treatment ◽  
Psychrophilic Yeast ◽  
Ribosomal Function ◽  
Physical Degradation ◽  
Thermal Stability Of

Ribosomes from the obligately psychrophilic yeast, Candida gelida, are rendered completely non-functional after exposure to 40 C for 5 minutes. This heat-induced impairment of ribosomal function is characterized by a reduced capacity to bind charged sRNA and is accompanied by physical degradation. Ribosomes from the mesophilic yeast, Candida utilis, however, are functionally and physically unaffected when subjected to similar treatment. The dissimilar thermal stabilities may be attributed to marked differences in the ribonucleoproteins present in the two species.

scholarly journals Improved Insights into Protein Thermal Stability: From the Molecular to the Structurome Scale

2016 ◽  
Author(s):  
Fabrizio Pucci ◽  
Marianne Rooman
Keyword(s):  
Thermal Stability ◽  
Amino Acid ◽  
Protein Stability ◽  
Large Scale ◽  
Molecular Level ◽  
Temperature Dependent ◽  
Natural Evolution ◽  
Multi Scale ◽  
Large Scale Analysis ◽  
Thermal Stability Of

AbstractDespite the intense efforts of the last decades to understand the thermal stability of proteins, the mechanisms responsible for its modulation still remain debated. In this investigation, we tackle this issue by showing how a multi-scale perspective can yield new insights. With the help of temperature-dependent statistical potentials, we analyzed some amino acid interactions at the molecular level, which are suggested to be relevant for the enhancement of thermal resistance. We then investigated the thermal stability at the protein level by quantifying its modification upon amino acid substitutions. Finally, a large scale analysis of protein stability - at the structurome level - contributed to the clarification of the relation between stability and natural evolution, thereby showing that the mutational profile of thermostable and mesostable proteins differ. Some final considerations on how the multi-scale approach could help unraveling the protein stability mechanisms are briefly discussed.

scholarly journals Temperature Dependence of the Pore Structure in Polyvinylidene Fluoride (PVDF)/Graphene Composite Membrane Probed by Electrochemical Impedance Spectroscopy

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1123 ◽  
Author(s):  
Qizhao Luo ◽  
Qing Huang ◽  
Zhe Chen ◽  
Lei Yao ◽  
Qiuming Fu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Pore Structure ◽  
Temperature Dependence ◽  
Composite Membrane ◽  
Electrochemical Impedance ◽  
Composite Membranes ◽  
Graphene Composite ◽  
Thermal Stability Of

In this paper, graphene was introduced in the PVDF to improve the thermal stability of the pore structure, which is the key feature for the membrane applied for the thermo-osmotic energy conversion (TOEC) process. The PVDF/graphene composite membranes were characterized by a scanning electron microscopy (SEM), a water contact angle measurement, and electrochemical impedance spectroscopy (EIS). It was found that the composite membranes exhibited improved surface hydrophobicity. Moreover, the pores in pure PVDF membrane would expand during the heat process while the existence of graphene in PVDF clearly suppressed the expansion, which implied better thermal stability of the pores in the composite membrane. According to the pore deformation time, the heat conductivities of the membranes were calculated and compared with each other. It confirmed that the composite membrane with higher graphene content exhibited enhanced heat conductivity. EIS can be used to monitor the temperature dependence of the pore structure in aqueous environments.

Carbon Nanotube/Polymer Nanocomposites: Improved or Reduced Thermal Stabilities?

2012 ◽  
Vol 722 ◽  
pp. 77-86
Author(s):  
Zhuo Li ◽  
Stewart J. Wilkins ◽  
Kyoung Sik Moon ◽  
C.P. Wong
Keyword(s):  
Thermal Stability ◽  
Free Radical ◽  
Carboxylic Acid ◽  
Polymer Nanocomposites ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Metal Catalyst ◽  
Thermal Stabilities ◽  
Pristine Cnts ◽  
Thermal Stability Of

The effects of carbon nanotubes (CNTs) on the thermal stability of CNT/polymer nanocomposites are discussed using CNT/silicone composites as a model compound. Pristine CNTs can improve the thermal stability of polymer composites due to the high thermal stability of CNTs, their network structure and free radical scavenging capabilities. However, impurities such as metal catalyst residues and defects such as carboxylic acid functional groups in CNTs can lead to decreased thermal stability of CNT/silicone nanocomposites. Acid purification is an efficient way to remove metallic impurities and can enhance free radical scavenging capabilities. However, controlling the amount of oxidation is important to avoid acid catalyzed thermal degradation induced by carboxylic acid groups on CNT surfaces.

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