scholarly journals The Role of Substrate Surface Roughness on in-Pack Aluminization Kinetics of Ni-Base Superalloy

2020 ◽  
Vol 4 (1) ◽  
pp. 15 ◽  
Author(s):  
Wojciech J. Nowak ◽  
Małgorzata Tomków ◽  
Patrycja Wierzba ◽  
Kamil Gancarczyk ◽  
Bartek Wierzba
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Temperature Oxidation ◽  
Diffusion Layers ◽  
Substrate Surface Roughness ◽  
Effect Of Surface

The Ni-base superalloys facing high temperature require further protection against high temperature oxidation. One of the most common methods providing high temperature oxidation resistance is the production of aluminide layers (NiAl-coatings). It is known that the thickness of produced diffusion layer can be controlled by the temperature and time of aluminization process. However, no research on the effect of surface roughness on aluminization kinetics was conducted so far. Then, to elucidate the effect of surface roughness on aluminization kinetics, diffusion layers were obtained by an in-pack aluminization method on the IN 617 alloy with differently prepared surfaces, namely polished, ground using 220 grit SiC paper and 80 grit SiC paper. The obtained results revealed that different surface preparation does not affect the chemical and phase composition of produced layers. However, a strong influence of surface preparation method on aluminide layers thicknesses was observed. Namely, it was found that the increase in substrate surface roughness results in an increase of aluminization kinetics. The dependence between surface roughness and thickness of aluminide layers was found to be logarithmic. Moreover, it was found that the aluminization kinetics is influenced, especially at early stages of the aluminization process.

scholarly journals Consequences of Different Mechanical Surface Preparation of Ni-Base Alloys during High Temperature Oxidation

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3529
Author(s):  
Wojciech J. Nowak ◽  
Krzysztof Siemek ◽  
Kamil Ochał ◽  
Barbara Kościelniak ◽  
Bartek Wierzba
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Surface Preparation ◽  
Optical Emission ◽  
Surface Region ◽  
Emission Spectrometry ◽  
Air Oxidation ◽  
Temperature Oxidation ◽  
Near Surface

The influence of surface roughness on its high temperature oxidation for an Ni-base superalloy was studied using laser profilometry, atomic force microscopy, mass change measurements, glow-discharge optical emission spectrometry, scanning electron microscopy, X-ray diffraction, and positron annihilation methods. The isothermal and cyclic air oxidation tests were performed at 1000 °C and showed dependence of oxidation behavior on surface roughness. Smoother surfaces oxidation resulted in the formation of a multilayered oxide scale consisting of NiO, Cr2O3, and internally oxidized Al2O3 while a rougher surface formed protective Al2O3 scale. The factors responsible for different oxidation behaviors were determined as higher concentration of vacancies and increased residual stresses in the near-surface region of studied alloys.

Role of Microstructure in High Temperature Oxidation.

1980 ◽  
Author(s):  
F. N. Rhines ◽  
R. G. Connell ◽  
Choi Jr. ◽  
M. S.
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Temperature Oxidation

scholarly journals Role of Hematite Formation on Blister Generation during High Temperature Oxidation of Steel

2012 ◽  
Vol 52 (12) ◽  
pp. 2254-2259 ◽  
Author(s):  
Yasumitsu Kondo ◽  
Hiroshi Tanei ◽  
Kohsaku Ushioda ◽  
Muneyuki Maeda
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Temperature Oxidation

Epitaxial Iridium Growth on Strontium Titanate

2000 ◽  
Vol 648 ◽  
Author(s):  
Z. Dai ◽  
A.P. Li ◽  
C. Bednarski ◽  
L. I. McCann ◽  
B. Golding
Keyword(s):  
Surface Roughness ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Electron Beam Evaporation ◽  
Layer By Layer ◽  
Epitaxial Relationship ◽  
Ion Channeling ◽  
Substrate Temperatures ◽  
Subsequent Layer

AbstractEpitaxial (100) iridium films have been grown on (100) SrTiO3 (STO) substrates by electron beam evaporation. The epitaxial relationship between the iridium film and STO substrate was determined to be Ir(001)[100]//STO(001)[100]. A systematic study of the role of STO substrate surface preparation, Ir thickness, and substrate temperature on Ir film crystallinity and morpholo- gy has been performed. The best Ir films typically have small Ir(200) XRD linewidths < 0.3 °, surface roughness of 0.2 nm, and low ion channeling yields, χmin≤ 4%, when deposited at 800 °C. Films generally become smoother with better crystallinity when the film thickness approaches 300 nm. A growth mode with initial island formation and subsequent layer-by-layer appears to take place at higher substrate temperatures, whereas at lower temperatures the film grows in a 3D mode.

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