Effects of Nickel on the Oxide/Metal Interface Morphology and Oxidation Rate During High-Temperature Oxidation of Fe–Cu–Ni Alloys

2010 ◽  
Vol 41 (3) ◽  
pp. 598-611 ◽  
Author(s):  
Lan Yin ◽  
Sukumar Balaji ◽  
Seetharaman Sridhar
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Interface Morphology ◽  
Metal Interface ◽  
Temperature Oxidation ◽  
Ni Alloys

scholarly journals Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2104 ◽  
Author(s):  
Hediyeh Dabbaghi ◽  
Keyvan Safaei ◽  
Mohammadreza Nematollahi ◽  
Parisa Bayati ◽  
Mohammad Elahinia
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Early Stage ◽  
Niti Alloy ◽  
Temperature Oxidation ◽  
X Ray ◽  
Rate Law ◽  
Parabolic Rate

In this study, the effect of the addition of Hf on the oxidation behavior of NiTi alloy, which was processed using additive manufacturing and casting, is studied. Thermogravimetric analyses (TGA) were performed at the temperature of 500, 800, and 900 °C to assess the isothermal and dynamic oxidation behavior of the Ni50.4Ti29.6Hf20 at.% alloys for 75 h in dry air. After oxidation, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to analyze the oxide scale formed on the surface of the samples during the high-temperature oxidation. Two stages of oxidation were observed for the NiTiHf samples, an increasing oxidation rate during the early stage of oxidation followed by a lower oxidation rate after approximately 10 h. The isothermal oxidation curves were well matched with a logarithmic rate law in the initial stage and then by parabolic rate law for the next stage. The formation of multi-layered oxide was observed for NiTiHf, which consists of Ti oxide, Hf oxide, and NiTiO3. For the binary alloys, results show that by increasing the temperature, the oxidation rate increased significantly and fitted with parabolic rate law. Activation energy of 175.25 kJ/mol for additively manufactured (AM) NiTi and 60.634 kJ/mol for AM NiTiHf was obtained.

scholarly journals High-Temperature Oxidation of FeCr(Ni) Alloys: The Behaviour After Breakaway

2017 ◽  
Vol 87 (3-4) ◽  
pp. 333-341 ◽  
Author(s):  
T. Jonsson ◽  
H. Larsson ◽  
S. Karlsson ◽  
H. Hooshyar ◽  
M. Sattari ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Ni Alloys

Characterising scale-breakdown mechanisms during high-temperature oxidation using EM

1990 ◽  
Vol 48 (4) ◽  
pp. 878-879
Author(s):  
P .N. Rowley ◽  
R. Brydson ◽  
J. A. Little ◽  
S. R. J. Saunders
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Rapid Development ◽  
Major Effect ◽  
Oxidation Behaviour ◽  
Metal Interface ◽  
Temperature Oxidation ◽  
High Temperature Steam ◽  
Fissure Formation ◽  
Insight Into

The microstructure and chemical composition of oxide films formed during the initial stages of high temperature oxidation have long been recognised as having a major effect on subsequent scaling behaviour. For example, the development of thick (>lμm) duplex scales on Fe-Cr alloys is assumed to occur via a mechanism of pore and fissure formation in the initial oxide (Atkinson, Tomlinson and Cory.) However, this process has rarely been observed using electron microscopy.The investigation of the oxidation behaviour of Fe-9Cr alloys in high temperature steam gives an insight into these scale breakdown processes. Within 3 minutes of the onset of oxidation, significant breakdown of the initially formed thin film occurs due to the development of readily visible fissures and pores at oxide grain boundaries (figure 1). This leads to the ready ingress of oxidant and the rapid development of a thick duplex Fe3O4/(Fe,Cr)3O4 oxide with a thin outer layer of α-Fe2O3 (figure 2). The extremely porous nature of this scale allows further inward diffusion of molecular oxidant, thereby instituting the continued growth of (Fe,Cr)3O4 at the scale/metal interface.

Effect of Yttrium Addition on High Temperature Oxidation Resistance of Co-10Cr-5Al Alloys

2011 ◽  
Vol 391-392 ◽  
pp. 606-610 ◽  
Author(s):  
Huai Shu Zhang ◽  
Hong Hua Zhang ◽  
Jun Huai Xiang ◽  
Shan Wang ◽  
Di Wu
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Temperature Oxidation ◽  
Linear Rate ◽  
Rate Law ◽  
Yttrium Addition ◽  
Parabolic Rate

The oxidation behavior of Co-10Cr-5Al-0.3Y alloy in 1 atm of pure O2 at 700°C was investigated. The addition of 0.3 at.%Y significantly increased the oxidation rate of the alloy and changed the oxidation behavior from the approximate parabolic rate law to linear rate law. The scale grown on the surface at 700°C was porous with many small voids and cracks, and was composed of an outer CoO layer and an inner complex layer rich in Al2O3 and Cr2O3 which were intermingled with yttric oxide and spinel Co(Cr, Al)2O4.

The Effect of Yttrium Ion Implantation on the High Temperature Oxidation Properties of NiAl

1990 ◽  
Vol 213 ◽  
Author(s):  
B.A. Pint ◽  
A. Jain ◽  
L.W. Hobbs
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Aluminum Content ◽  
Cyclic Testing ◽  
Cation Diffusion ◽  
Temperature Oxidation ◽  
Oxidation Properties ◽  
Yttrium Ion ◽  
Very High

ABSTRACTNiAl was ion implanted with yttrium (2×1016 cm−2) in order to study its effect on the very high temperature (1000–1500°C) oxidation properties. At 1000°C, implanted Y stabilizes the faster growing θ-Al2O3 phase, thus slightly increasing the oxidation rate. At 1200°C, where predominantly α-Al2 O3 is formed with and without Y, there is a factor of 4 reduction in the oxidation rate. However at higher than 1200°C, there is little effect by Y on the oxidation rate. Cyclic testing showed that the Y implant had an imperfect and short-lived improvement on adherence relative to other Y-containing alloys. Variations in aluminum content from 23.5 to 36.0wt%(40–55at%) had little effect on the oxidation properties. Initial experiments at 1500°C with a novel Rh marker indicate that alumina grows at least partially by outward cation diffusion both with and without Y.

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