High Temperature Oxidation Behavior of TiNi Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 853-856 ◽  
Author(s):  
J.H. Ko ◽  
Dong Bok Lee
Keyword(s):  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Tini Alloy ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
Ni Alloy ◽  
Embedded Particles ◽  
High Temperature Oxidation Behavior ◽  
Better Than

The oxidation behavior of the equiatomic TiNi alloy was investigated at 600-900oC. The oxidation resistance of the TiNi alloy was better than the pure Ti alloy, but worse than the pure Ni alloy. The oxide scales consisted of TiO2, with and without embedded particles of TiNiO3 and Ni. The subscale matrix phase was (TiNi3+TiNi) at 600oC, TiNi3 at 700oC, (Ni+TiNi3) at 800oC, and Ni at 900oC. Oxidation was mainly governed by the inward diffusion of oxygen, and the outward diffusion of Ti and a bit of Ni. Detailed microstructures and the oxidation mechanism are proposed.

High-Temperature Oxidation Behavior of Fe-Si-Ce Alloys

2016 ◽  
Vol 35 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Yong Su ◽  
Shunke Zhang ◽  
Guangyan Fu ◽  
Qun Liu ◽  
Yuanze Tang
Keyword(s):  
Grain Size ◽  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Mass Gain ◽  
Optical Microscope ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Beneficial Effects ◽  
Negative Effect ◽  
High Temperature Oxidation Behavior

AbstractThe oxidation behavior of Fe-Si-Ce alloys with different Ce content at 1,173 and 1,273 K has been studied by means of optical microscope (OM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). Results show that the Ce addition refines the grain size of Fe-Si alloys, and correspondingly the grain size of the oxides decreases, which increases the grain boundary concentration and promotes the short-path diffusion of the alloying elements and oxygen. During oxidation, the positive effect of the grain refinement on the oxidation behavior of the alloy is more obvious than negative effect, so the Ce addition improves the oxidation resistances of the Fe-3Si alloys. Compared to Fe-3Si-0.5Ce alloy, Fe-3Si-5.0Ce alloy has the larger mass gain for the preferential oxidation of the excessive content of Ce exceeding its beneficial effects. The rare earth Ce changes the oxidation mechanism of Fe-Si alloys. Oxygen penetrates the oxide scales and reacts preferentially with Ce-rich phases, which results in the pinning effect and improves the adhesion of the oxide scales.

Effect of Compressive Stress on the High-Temperature Oxidation Behavior of a Fe-20Ni Alloy in Air

2018 ◽  
Vol 921 ◽  
pp. 168-176
Author(s):  
Chang Hai Zhou ◽  
Rui Yun Pan ◽  
Hai Tao Ma
Keyword(s):  
Compressive Stress ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Oxide Scales ◽  
External Scale ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
X Ray ◽  
High Temperature Oxidation Behavior ◽  
Kinetics Of

The oxidation behavior of Fe-20Ni alloy under compressive stress in air was studied at 800, 900 °C. The results examined by using scanning electron microscope (SEM) and X-ray diffraction (XRD) indicates that the oxide scales were consisted of an external scale and a subscale which has an intragranular scale (above 5 h at 800 °C and 900 °C) and an intergranular scale. Compared with the unstressed specimen, the growth kinetics of external scale was accelerated by an applied compressive stress. Besides, the compressive stress induced an increase in the growths of intragranular scale and intergranular scale formed on the specimens oxidized at 900 °C. However, the effect of compressive stress on the growth of intergranular scale and intragranular scale was not obvious in the case of 800°C. In addition, cracks developed in the subscale for the specimens oxidized under 2.5 MPa compressive stress when the oxidation time exceeded 20 h.

High-temperature oxidation behavior of arc ion plated NiCoCrAlYSiB coatings on cobalt-based superalloy

2006 ◽  
Vol 21 (3) ◽  
pp. 737-746 ◽  
Author(s):  
Y.J. Tang ◽  
Q.M. Wang ◽  
F.H. Yuan ◽  
J. Gong ◽  
C. Sun
Keyword(s):  
Cross Sections ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Alloy Element ◽  
Oxide Scales ◽  
Protective Oxide ◽  
Temperature Oxidation ◽  
Ion Plating ◽  
Aluminide Coatings ◽  
High Temperature Oxidation Behavior

NiCoCrAlYSiB coatings were deposited on the Co-based superalloy K40 by arc ion plating (AIP). The oxidation behavior of the bare alloy and of the coated specimens was tested in static air for 200 h at 1000 °C and 100 h at 1050 °C. The results showed that the oxidation rate of the system was greatly reduced by the addition of the NiCoCrAlYSiB coatings. Thin and adherent α–Al2O3 scales that formed on the coated specimens protected the substrates from further oxidation attack while non-protective oxide scales, mainly of Cr2O3 and CoCr2O4, appeared on bare K40 alloy. Element profiles on metallographic cross sections indicated that apparent interdiffusion occurred between the coatings and the substrates. The interdiffusion behavior and the resulting microstructure were investigated. As compared to aluminide coatings, NiCoCrAlYSiB coatings have less influence on the substrate microstructure.

scholarly journals High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4259
Author(s):  
Lin Wang ◽  
Quanqing Zeng ◽  
Zhibao Xie ◽  
Yun Zhang ◽  
Haitao Gao
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
High Entropy Alloy ◽  
Spinel Type ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
High Entropy ◽  
High Temperature Oxidation Behavior

The oxidation behavior of an equimolar Cr-Mn-Fe-Co high-entropy alloy (HEA) processed by 3D laser printing was investigated at 700 °C and 900 °C. The oxidation kinetics of the alloy followed the parabolic rate law, and the oxidation rate constant increased with the rising of the temperature. Inward diffusion of oxygen and outward diffusion of cations took place during the high-temperature oxidation process. A spinel-type oxide was formed on the surface, and the thickness of the oxide layer increased with the rising of experimental temperature or time. The exfoliation of the oxide layer took place when the test was operated at 900 °C over 12 h. During oxidation tests, the matrix was propped open by oxides and was segmented into small pieces. The formation of loose structures had great effects on the high-temperature oxidation resistance of the HEA.

scholarly journals High-Temperature Oxidation Behavior of Fe–1Cr–0.2Si Steel

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 509
Author(s):  
Mingxin Hao ◽  
Bin Sun ◽  
Hao Wang
Keyword(s):  
High Temperature ◽  
Iron Oxide ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Steel Tube ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
High Temperature Oxidation Behavior ◽  
Mixed Layers ◽  
Oxidation Weight Gain

In the case of Fe–1Cr–0.2Si steel, tube furnace oxidation was carried out for 120 min and 30 min. These studies, along with the high-temperature oxidation behavior of Fe–1Cr–0.2Si steel, were examined from 700 to 1100 °C. It has been observed that with an increase in the oxidation time, the oxidation weight gain per unit area of Fe–1Cr–0.2Si steel changed from a linear to a parabolic relationship. The time was shortened when the oxidation phase was linear. When the oxidation temperature exceeded 900 °C, the value of WTransition decreased, and the oxidation rule changed. It could be considered that overall, the iron oxide structure of Fe–1Cr–0.2Si steel is divided into two layers. The formation of an outer oxide of iron is mainly caused by the outward diffusion of cation, while the inward diffusion of O ion forms the inner oxides of chromium and silicon. As the temperature increases, the thickness of the outer iron oxide gradually increases, and the thickness ratio of the inner mixed layers of chromium- and silicon-rich oxides decreases; however, the degree of enrichment of Cr and Si in the mixed layer increases. After high-temperature oxidation, Cr and Si did not form a composite oxide but were mechanically mixed in the form of FeCr2O4 and Fe2SiO4, and no significant delamination occurred.

Post-Weld Oxidation Behavior of AA6061 Al Alloy

2011 ◽  
Vol 399-401 ◽  
pp. 2087-2090
Author(s):  
Nur Azida Che Lah ◽  
Azman Jalar ◽  
Norinsan Kamil Othman
Keyword(s):  
Oxidation Behavior ◽  
Welded Joint ◽  
Oxidation Mechanism ◽  
Al Alloy ◽  
Oxide Scales ◽  
Parent Metal ◽  
Alloying Element ◽  
Protective Oxide ◽  
Temperature Oxidation ◽  
Oxidation Exposure

Welded AA6061 Al alloy using ER5356 (Al-5Mg) filler was oxidized in flowing air gas for 40hrs at 600oC at a total pressure of approximately 1 atm. The morphology and microstructure of welded joint after exposure was characterized by using optical metallurgy microscopy and Scanning Electron Microscope (SEM). Different oxide morphologies and textures were observed on parent and fusion metal due to the differences of the alloying element. The oxidation mechanism represented a complex reaction occur where the morphology and phase formation of the oxide shows the protective oxide scales showed the protective oxide were developed on parent metal side, meanwhile non-protective oxide scale formed on fusion metal of the welded Al alloy. It can be concluded that the welded area failed to resist oxidation behavior compared to the parent metal. The differ results are discuss in term of microstructure changes caused by high temperature oxidation exposure and alloying element.

scholarly journals Oxidation of Al-Co Alloys at High Temperatures

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3152
Author(s):  
Patrik Šulhánek ◽  
Marián Drienovský ◽  
Ivona Černičková ◽  
Libor Ďuriška ◽  
Ramūnas Skaudžius ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Simultaneous Thermal Analysis ◽  
Temperature Oxidation ◽  
Practical Applications ◽  
High Temperature Oxidation Behavior ◽  
Co Alloys

In this work, the high temperature oxidation behavior of Al71Co29 and Al76Co24 alloys (concentration in at.%) is presented. The alloys were prepared by controlled arc-melting of Co and Al granules in high purity argon. The as-solidified alloys were found to consist of several different phases, including structurally complex m-Al13Co4 and Z-Al3Co phases. The high temperature oxidation behavior of the alloys was studied by simultaneous thermal analysis in flowing synthetic air at 773–1173 K. A protective Al2O3 scale was formed on the sample surface. A parabolic rate law was observed. The rate constants of the alloys have been found between 1.63 × 10−14 and 8.83 × 10−12 g cm−4 s−1. The experimental activation energies of oxidation are 90 and 123 kJ mol−1 for the Al71Co29 and Al76Co24 alloys, respectively. The oxidation mechanism of the Al-Co alloys is discussed and implications towards practical applications of these alloys at high temperatures are provided.

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