An Advanced Technique for High Temperature X-Ray Elastic Constant and Stress Investigations

1992 ◽  
Vol 36 ◽  
pp. 411-422
Author(s):  
Chun Liu ◽  
Jean-Lou Lebrun ◽  
François Sibieude
Keyword(s):  
High Temperature ◽  
Elastic Constant ◽  
High Temperature Oxidation ◽  
Differential Method ◽  
Stress Evolution ◽  
Advanced Technique ◽  
Temperature Oxidation ◽  
X Ray ◽  
Refractory Alloys

AbstractA high temperature in situ X-Tay diffraction (HTXRD) instrument was devised for residual stress (RS) and X-ray elastic constant (XECs) investigations. The aim was to gain a better understanding of the stresses developed during high temperature oxidation, which is essential for the lifetime improvement of refractory alloys. The investigators use sin2ψ method to survey the stress evolution during oxidation in both the scale and the substrate, and differential method to determine the XECs that relate the measured/measurable deformation to the stress state of the materials studied. The stresses on the Ni/NiO system are measured in situ. The XECs are determined on XC75 steel samples. This paper presents the theories of stresses and XECs determined by HTXRD and briefly discusses the experimental results.

Effect of B on the Microstructures and High Temperature Oxidation Resistance of a Nb-Si System In Situ Composite

2007 ◽  
Vol 546-549 ◽  
pp. 1489-1494 ◽  
Author(s):  
Ai Qin Liu ◽  
Shu Suo Li ◽  
Lu Sun ◽  
Ya Fang Han
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Arc Melting ◽  
The Matrix

Nb-16Si-24Ti-6Cr-6Al-2Hf-xB(x=0, 0.5, 1, 2, 4, 6) in situ composites were prepared by arc-melting. Microstructure and the effect of boron on 1250C oxidation resistance of the composites were investigated by scanning electron microscopy(SEM) and X-ray energy disperse spectrum(EDS) as well as X-ray diffraction(XRD). The experimental results showed that the high temperature oxidation resistance of the alloy was remarkably improved by adding proper amount of boron. This may be resulted from several beneficial roles of boron, i.e., boron improves the resistance of Nb5Si3 by solid solution strengthening, inhibits the diffusion of oxygen in the matrix, improves the adherence between the oxide scale and the substrate and increases the cracking resistance of the oxide scale.

In situ X-ray diffraction contribution to the high temperature oxidation study of FeCrAl alloys

2002 ◽  
Vol 12 (6) ◽  
pp. 39-46
Author(s):  
R. Cueff ◽  
H. Buscail ◽  
E. Caudron ◽  
C. Issartel ◽  
S. Perrier ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
X Ray ◽  
Oxidation Study ◽  
Fecral Alloys

Ionic Transport under Chemical Potential Gradients - Kinetic Demixing and Decomposition in Metal Oxides and Scale Growth in High-Temperature Oxidation

2011 ◽  
Vol 696 ◽  
pp. 28-33
Author(s):  
Manfred Martin
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Elevated Temperatures ◽  
Chemical Potential ◽  
Transport Processes ◽  
Temperature Oxidation ◽  
X Ray ◽  
Kinetic Decomposition ◽  
Potential Gradients

In oxides which are exposed to thermodynamic potential gradients, transport processes of the mobile components occur. These transport processes and the coupling between different processes are not only of fundamental interest, but are also the origin of degradation processes, such as kinetic demixing, kinetic decomposition, and changes in the morphology of the material. The kinetics of high temperature oxidation processes of metals can be studiedin situby X-ray absorption spectroscopy (XAS), optical microscopy and X-ray diffraction (XRD) at elevated temperatures and defined oxygen partial pressures. As an example, thein situXAS investigation of the oxidation of cobalt, forming layers of CoO and Co3O4, will be discussed.

In Situ X-Ray Diffractometry of Cristobalite Formation during High-Temperature Oxidation of SiC Films

1998 ◽  
Vol 37 (Part 1, No. 7A) ◽  
pp. 4160-4161 ◽  
Author(s):  
Toshiki Kingetsu ◽  
Kenjiro Ito ◽  
Masaharu Takehara
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Sic Films

High Temperature Oxidation of Nickel-based Cermet Coatings Composed of Al2O3 and TiO2 Nanosized Particles

2014 ◽  
Vol 33 (5) ◽  
pp. 407-419 ◽  
Author(s):  
M. A. Farrokhzad ◽  
T. I. Khan
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Volume Fraction ◽  
Nickel Matrix ◽  
Applied Current ◽  
In Situ Combustion ◽  
Temperature Oxidation ◽  
Cermet Coatings ◽  
X Ray

AbstractNew technological challenges in oil production require materials that can resist high temperature oxidation. In-Situ Combustion (ISC) oil production technique is a new method that uses injection of air and ignition techniques to reduce the viscosity of bitumen in a reservoir and as a result crude bitumen can be produced and extracted from the reservoir. During the in-situ combustion process, production pipes and other mechanical components can be exposed to air-like gaseous environments at extreme temperatures as high as 700 °C. To protect or reduce the surface degradation of pipes and mechanical components used in in-situ combustion, the use of nickel-based ceramic-metallic (cermet) coating produced by co-electrodeposition of nanosized Al2O3 and TiO2 have been suggested and earlier research on these coatings have shown promising oxidation resistance against atmospheric oxygen and combustion gases at elevated temperatures. Co-electrodeposition of nickel-based cermet coatings is a low-cost method that has the benefit of allowing both internal and external surfaces of pipes and components to be coated during a single electroplating process. Research has shown that the volume fraction of dispersed nanosized Al2O3 and TiO2 particles in the nickel matrix which affects the oxidation resistance of the coating can be controlled by the concentration of these particles in the electrolyte solution, as well as the applied current density during electrodeposition. This paper investigates the high temperature oxidation behaviour of novel nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in a nickel matrix and produced by coelectrodeposition technique as a function of the concentration of these particles in the electrolyte solution and applied current density. For this purpose, high temperature oxidation tests were conducted in dry air for 96 hours at 700 °C to obtain mass changes (per unit of area) at specific time intervals. Statistical techniques as described in ASTM G16 were used to formulate the oxidation mass change as a function of time. The cross-section and surface of the oxidized coatings were examined for both visual and chemical analyses using wavelength dispersive x-ray spectroscopy (WDS) element mapping, X-ray Diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDS). The results showed that the volume fraction for each type of particle in the nickel matrix corresponded to its partial molar concentration in the electrolyte solutions. Increase in volume fraction of particles in the nickel matrix was correlated to lower oxidation rates. It was concluded that formation of Ni3TiO5 and NiTiO3 compounds can reduce the oxidation rate of cermet coatings by capturing some inward diffusing oxygen ions resulting in a lower number of nickel cations diffusing upward into the oxide layer.

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