In situ and ex situ studies of microstructure evolution during high-temperature oxidation of ZrN hard coating

2015 ◽  
Vol 97 ◽  
pp. 9-12 ◽  
Author(s):  
Z.B. Qi ◽  
Z.T. Wu ◽  
H.F. Liang ◽  
D.F. Zhang ◽  
J.H. Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Microstructure Evolution ◽  
High Temperature Oxidation ◽  
Ex Situ ◽  
Hard Coating ◽  
Temperature Oxidation

High-temperature oxidation of CoGa: Influence of the crystallographic orientation on the oxidation rate

2002 ◽  
Vol 17 (10) ◽  
pp. 2489-2498 ◽  
Author(s):  
U. Koops ◽  
D. Hesse ◽  
M. Martin
Keyword(s):  
High Temperature ◽  
Crystallographic Orientation ◽  
High Temperature Oxidation ◽  
Elevated Temperatures ◽  
Electron Backscatter Diffraction ◽  
Ex Situ ◽  
Temperature Oxidation ◽  
Transmission Electron ◽  
Backscatter Diffraction

The crystallographic orientation plays an important role in high-temperature oxidation of the intermetallic compound CoGa. When CoGa is exposed to air at elevated temperatures, the oxide β–Ga2O3 is formed, and different scale growth rates are observed, depending on the crystallographic orientation of the CoGa grains. This dependence is a consequence of the anisotropy of the gallium diffusion rate through the β–Ga2O3 scale and of a topotaxial orientation relationship occurring between β–Ga2O3 and CoGa. The combination of ex situ techniques, such as transmission electron microscopy and electron backscatter diffraction with optical microscopy, applied in situ resulted in a thorough understanding of these relations and of the oxidation process in general.

High temperature oxidation of rare earth permanent magnets. Part 1 – Microstructure evolution and general mechanism

2018 ◽  
Vol 133 ◽  
pp. 374-385 ◽  
Author(s):  
Muhamad Firdaus ◽  
M. Akbar Rhamdhani ◽  
W. John Rankin ◽  
Mark Pownceby ◽  
Nathan A.S. Webster ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Microstructure Evolution ◽  
High Temperature Oxidation ◽  
Permanent Magnets ◽  
General Mechanism ◽  
Temperature Oxidation

scholarly journals High-temperature oxidation resistance of VCps-reinforced Fe-matrix composites using an in-situ reaction

AIP Advances ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 015319
Author(s):  
Pinghu Chen ◽  
Ruiqing Li ◽  
Ripeng Jiang ◽  
Songsheng Zeng ◽  
Yun Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Matrix Composites ◽  
Temperature Oxidation ◽  
In Situ Reaction

In Situ Measurement of the Phase Transformation Behavior of Al2O3 Scale during High-Temperature Oxidation using Synchrotron Radiation

2011 ◽  
Vol 696 ◽  
pp. 63-69 ◽  
Author(s):  
Shigenari Hayashi ◽  
Isao Saeki ◽  
Yoshitaka Nishiyama ◽  
Takashi Doi ◽  
Shoji Kyo ◽  
...  
Keyword(s):  
High Temperature ◽  
Synchrotron Radiation ◽  
High Temperature Oxidation ◽  
Structural Changes ◽  
Lattice Parameter ◽  
Transformation Behavior ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
Diffraction Peaks

Very thin Fe-coatings, ~50nm, were found to suppress metastable Al2O3 formation on Fe-50Al and Ni-50Al alloys in our previous study. The authors proposed a mechanism whereby α-Al2O3 precipitates from the Al-saturated Fe2O3, which was formed during initial oxidation, since α-Al2O3 and α-Fe2O3 have isomorphous structures. In order to confirm the proposed mechanism, in-situ measurements were made of structural changes in the oxide scales formed on FeAl with and without Fe coating during heating and subsequent isothermal high temperature oxidation by synchrotron radiation with a two-dimensional X-ray detector. Diffraction peaks from Fe2O3 were initially observed at around 350°C on Fe-coated samples. The lattice parameter of the Fe2O3 initially increased linearly due to thermal expansion, but then rapidly decreased due to the formation of a solid solution of Fe2O3-Al2O3. α-Al2O3 started to appear at around 800°C, but no peaks from metastable Al2O3 were observed. The diffraction peaks from the α-Al2O3 on Fe-coated samples consisted of two distinct peaks, indicating that the α-Al2O3 had two different lattice parameters. These results suggest that the α-Al2O3 was formed not only by precipitation from the Al-saturated Fe2O3, but also by oxidation of Al in the substrate.

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