scholarly journals Effects of Cr, W, and Mo on the High Temperature Oxidation of Ni-Based Superalloys

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2934 ◽  
Author(s):  
Si-Jun Park ◽  
Seong-Moon Seo ◽  
Young-Soo Yoo ◽  
Hi-Won Jeong ◽  
HeeJin Jang
Keyword(s):  
Oxide Layer ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Mass Gain ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
Sectional Structure ◽  
And Diffusion ◽  
Valence Number ◽  
Al Oxide

The oxidation behavior of Ni–9.5Co–(8~12)Cr–(2.5~5.5)Mo–(4~8)W–3Al–5Ti–3Ta–0.1C–0.01B alloys was investigated at 850 °C and 1000 °C The mass change, the phase of oxides, and the cross-sectional structure of specimens were analyzed after cyclic oxidation tests. The oxide scale was composed mainly of Cr2O3 and NiCr2O4, but NiO, TiO2, and CrTaO4 were also found. Al2O3 was formed beneath the Cr oxide layer. The Cr oxide layer and internal Al oxide acted as barriers to oxidation at 850 °C, while Al oxide was predominantly protective at 1000 °C. Cr increased the mass gain after oxidation test at both temperatures. Mo increased the oxidation rate at 850 °C but decreased the oxidation rate at 1000 °C. W slightly increased the mass gain at 850 °C but did not produce a significant effect at 1000 °C. The effects of Cr, Mo, W, and the temperature were discussed as well as the volatilization of oxides, the valence number of elements, and diffusion retardation.

Oxidation of Aluminum Nitride for Defect Characterization

2005 ◽  
Vol 892 ◽  
Author(s):  
James Edgar ◽  
Z. Gu ◽  
K. Taggart ◽  
J. Chaudhuri ◽  
L. Nyakiti ◽  
...  
Keyword(s):  
Aluminum Nitride ◽  
Oxide Layer ◽  
Oxidation Rate ◽  
Surface Condition ◽  
Initial Oxidation ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
Transmission Electron ◽  
Crystalline Oxide ◽  
Dry Oxidation

AbstractThe thermal oxidation of aluminum nitride was developed as a means to study defects in bulk aluminum nitride crystals. The oxidation kinetics was established for the dry oxidation of highly textured AlN polycrystals produced by sublimation-recombination crystal growth in a tungsten furnace. Despite seeding on polycrystalline tungsten, the grains were predominantly [0001] oriented as verified by electron backscattering diffraction (EBSD). The oxidation rate is dependent on the crystal’s orientation, polarity, stress, and surface condition, thus oxidation decorates grain boundaries, polishing scratches, and inversion domains by producing oxide layers of different thicknesses. The initial oxidation rate of nitrogen polar (0001) AlN is approximately 25% faster than on aluminum polar crystals. Low temperature (800 °C) dry oxidation produced an amorphous oxide layer and generated a high density of defects (vacancies, stacking faults, and dislocations) in the nitride near the oxide/nitride interface, as observed by cross-sectional transmission electron microscopy. In contrast, high temperature oxidation (1000 °C) produced a crystalline oxide layer, and left the nitride free of observable defects.

Oxidation of Tantalum Nitride

2013 ◽  
Vol 761 ◽  
pp. 125-129 ◽  
Author(s):  
Kazuya Hamaguchi ◽  
Tomoyuki Tsuchiyama ◽  
Junichi Matsushita
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
Human Body ◽  
Body Fluid ◽  
High Temperature Oxidation ◽  
Tantalum Oxide ◽  
Mass Gain ◽  
Tantalum Nitride ◽  
Oxidation Temperature ◽  
Temperature Oxidation

Tantalum (Ta) can be use a suture for operation and implant material in order not to react with body fluid and stimulate a human body. In this study, the stable oxide of a tantalum, tantalum oxide layer produced by oxidation of the tantalum nitride, TaN powders by high temperature oxidation were investigated in order to determine the possibility of its a distributed aid for biomaterial composite such as an artificial root etc. The sample, TaN powder oxidized at high temperature exhibited a steady mass gain with increasing oxidation temperature. Based on the results of the XRD, tantalum oxide, Ta2O5 was detected on the samples. It is considered, the TaN showed a good oxidation film produced by high temperature oxidation.

Study on Oxidation Behavior of (W,Mo)Si2 Powders in Air at 400, 500 and 600°C

2007 ◽  
Vol 534-536 ◽  
pp. 1289-1292
Author(s):  
Pei Zhong Feng ◽  
Xuan Hui Qu ◽  
Xiao Hong Wang ◽  
Akthar Farid
Keyword(s):  
Oxidation Rate ◽  
Volume Expansion ◽  
Mass Gain ◽  
Main Reaction ◽  
Reaction Products ◽  
Low Temperature Oxidation ◽  
Amorphous Sio2 ◽  
Temperature Oxidation ◽  
Mass Volume ◽  
Lower Oxidation

The oxidation of (W,Mo)Si2 powders has been examined at 400, 500 and 600°C for 12.0 hours in air. It was shown that the low temperature oxidation resistance of (W,Mo)Si2 was worse than that of MoSi2, and they showed great changes in mass, volume and colour. At 500°C, the amount of volume expansion of (W,Mo)Si2 was as high as about 7~8 times and color changed from black to yellow after 4.0h with MoO3, WO3, (W,Mo)O3 and amorphous SiO2 as main reaction products. It took about 8.0h to obtain the same results for MoSi2. The mass gain and oxidation rate were relatively slower at 400°C and 600°C than that at 500°C. These were probably due to the lower oxidation rate at 400°C and the protective silica glass on surface of powders formed from the volatilization of MoO3, WO3 and (W,Mo)O3 at 600°C, which would restrain the diffusion of molybdenum from matrix to exterior and oxygen from outside to inside and the further accelerated oxidation.

Research on the Si-Ti High Temperature Oxidation-Resistant Coatings for Tantalum Alloys

2013 ◽  
Vol 785-786 ◽  
pp. 45-51
Author(s):  
Pei Pei Song ◽  
Jun Le ◽  
Feng Ye ◽  
Xiao Cheng Sheng ◽  
Xiao Wei Zhang
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
X Ray ◽  
Different Temperatures ◽  
Slurry Method ◽  
Sectional Structure

Si-Ti coatings were prepared on the surface of T-222 alloy by fused slurry method at different temperatures (1425-1500°C). Microstructure and composition of the coatings were characterized and analysed through scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray spectrometry (EDS) respectively. The coating fabricated at 1450°C exhibited excellent structure compatible with high temperature oxidation resistance. Its surface is relatively smooth with few holes and cracks and the main phase on the surface is (Ti, Ta)Si that possesses outstanding corrosion resistance. Moreover, the cross-sectional structure of the coating is smooth and compact which can effectively prevent O2 from permeation. The isothermal oxidation behaviors in pure O2 atmosphere at 1500°C for 2h finally demonstrate that the optimum coating temperature is 1450°C.

High-temperature oxidation of ion-plated TiN and TiAlN films

1993 ◽  
Vol 8 (5) ◽  
pp. 1093-1100 ◽  
Author(s):  
Hiroshi Ichimura ◽  
Atsuo Kawana
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Mass Gain ◽  
Activation Energies ◽  
Ion Diffusion ◽  
Temperature Oxidation ◽  
Al Content ◽  
Rate Determining Step ◽  
Apparent Activation Energies

The high-temperature oxidation of TiN, Ti0.9Al0.1N, and Ti0.6Al0.4N films which were deposited onto stainless steel substrates using an arc ion-plating apparatus was studied at temperatures ranging from 923 to 1173 K for 0.6 to 60 ks in air. The oxidation rate obtained from mass gain as a function of time was found to fit well to a parabolic time dependence. From their temperature dependence, the apparent activation energies of oxidation were determined. With increasing Al contents, the oxidation rate decreased, and the activation energies of oxidation reaction increased. Formed oxide layers were analyzed by XRD, SEM, and EPMA. With increased Al content in TiAlN films, the rate-determining step changes from oxygen ion diffusion in formed rutile to oxygen or aluminum ion diffusion in the formed Al2O3 layer.

scholarly journals Investigation on the High-Temperature Oxidation Resistance of Ni-(3~10) Ta and Ni-(3~10) Y Alloys

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 97 ◽  
Author(s):  
Hang Duan ◽  
Yan Liu ◽  
Tiesong Lin ◽  
Hui Zhang ◽  
Zhengren Huang
Keyword(s):  
Oxide Layer ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Vacancy Concentration ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
Vacuum Arc ◽  
Oxygen Vacancy Concentration ◽  
Positive Role ◽  
Temperature Oxidation

Ni-(3~10) Ta and Ni-(3~10) Y alloys were fabricated by vacuum arc melting. The oxidation resistance of the alloys was studied by cyclic and isothermal oxidation tests at 800 °C in static air. The present work focused on the investigation of the effects of the alloying elements (Ta and Y) on the oxidation behavior of Ni-based alloys. The oxidation behavior of alloys was evaluated by mass gain, composition, as well as the microstructure of oxidized products. The experimental results indicated that Ta at a low content (3 wt %) had a positive role in enhancing oxidation resistance by decreasing the oxygen vacancy concentration of the oxide layer to prevent the inward diffusion of oxygen during oxidation, and the mass gain decreased from 2.9 mg·cm−2 to 1.7 mg·cm−2 (800 °C/200 h), while Y (3~10 wt %) degraded the oxidation resistance. However, it is worth mentioning that the pinning effect of Y2O3 increased the adhesion between the substrate and oxide layer by changing the growing patterns of the oxide layer from a plane growth to fibrous growth. Among the results, the bonding of the substrate and oxide layer was best in the Ni-3Y alloys.

scholarly journals High-Temperature Oxidation Behavior of Fe–10Cr Steel under Different Atmospheres

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3453
Author(s):  
Lei Cheng ◽  
Bin Sun ◽  
Chongyang Du ◽  
Wei Gao ◽  
Guangming Cao
Keyword(s):  
Water Vapor ◽  
Iron Oxide ◽  
Oxide Layer ◽  
Internal Oxidation ◽  
Oxidation Kinetics ◽  
Oxidation Temperature ◽  
Oxide Scales ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
Air Atmosphere

Using a thermogravimetric analyzer (TGA), Fe–10Cr steel was oxidized in dry air and in a mixed atmosphere of air and water vapor at a relative humidity of 50% and a temperature of 800–1200 °C for 1 h. The oxidation weight gain curves under the two atmospheres were drawn, the oxidation activation energy was calculated, and the phase and cross-sectional morphology of the iron oxide scales were analyzed and observed by X-ray diffractometry (XRD) and optical microscopy (OM). The results showed that when the oxidation temperature was 800 °C, the spheroidization of Fe–10Cr steel occurred, and the oxidation kinetics conformed to the linear law. At 900–1200 °C, the oxidation kinetics followed a linear law in the preliminary stage and a parabolic law in the middle and late stages. In an air atmosphere, when the oxidation temperature reached 1200 °C, Cr2O3 in the inner oxide layer was partially ruptured. In an atmosphere with a water vapor content of 50%, Cr2O3 at the interface reacted with H2O to generate volatile CrO2(OH)2, resulting in a large consumption of Cr at the interface. At the same time, a large number of voids and microcracks appeared in the iron oxide layer, which accelerated the entry of water molecules into the substrate, as well as the oxidation of Fe–10Cr steel, and caused the iron oxide scales to fall off. Due to the volatilization of Cr2O3 and the conversion from internal oxidation to external oxidation, the internal oxidation zone (IOZ) of Fe–10Cr steel under water vapor atmosphere decreased or even disappeared.

Low-temperature oxidation of Moss—Mo3Si alloys doped by Sc or Y in air and vapor-air mixture

2021 ◽  
pp. 24-32
Author(s):  
L.U. Udoeva ◽  
◽  
K.V. Pikulin ◽  
S.N. Agafonov ◽  
A.V. Larionov ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxide Layer ◽  
Oxidation Rate ◽  
Surface Oxide ◽  
Surface Oxide Layer ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Dry Air ◽  
Humid Environment

The effect of Sc or Y additives (3% (at.)) on oxidation of Moss—Mo3Si composite in the air and a vapor-air environment (10% H2O) has been studied. It was shown that when heating in the air (500 °C, 100 h) on the surface of samples formed a layer of scale from the mixture of MoO3 + SiO2 and MoO3. Doped alloys were found to oxidize much slower than binary composites. Two process periods with different velocity constants were identified by analysis of kinetic functions. The first period was limited by the oxidation rate of the alloy components and the second one — by sublimation of MoO3 from the surface oxide layer. Sublimation in a humid environment was faster than in the dry air.

Effect of Temperature on Structure of Outer Fe Oxide Layer of Fe-2.2Si Alloy

2013 ◽  
Vol 652-654 ◽  
pp. 1009-1015 ◽  
Author(s):  
Xiao Jiang Liu ◽  
Guang Ming Cao ◽  
Yong Quan He ◽  
Tao Jia ◽  
Zhen Yu Liu
Keyword(s):  
Acid Solution ◽  
Oxide Layer ◽  
Effect Of Temperature ◽  
Elemental Distribution ◽  
Internal Oxide ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
Fe Oxide ◽  
Thermogravimetric Analyzer ◽  
Hot Rolled

Red scale is the main surface defect of hot-rolled silicon steel plate due to the formation of fayalite. Studies have been done on high temperature oxidation of Fe-Si alloy, but effect of temperature on structure of outer Fe oxide layer is not fully discussed. Thermogravimetric analyzer (TGA) was used to simulate isothermal 60-min oxidation process of Fe-2.2Si alloy under air condition at 700°C-1200°C. Cross-sectional scale morphology and elemental distribution of the oxide layer were investigated by electron probe microanalysis (EPMA). It is found that in order to observe internal oxide precipitates clearly it is helpful that the sample is etched with nitric acid solution in alcohol firstly and then etched with hydrochloric acid solution in alcohol. At 700°C-1150°C outer Fe oxide layer is mostly composed of Fe2O3 and at 1200°C it consists of FeO + Fe3O4 + Fe2O3 + mixture of FeO/Fe2SiO4.

Transmission Electron Microscopy Studies of Aluminum Oxidation

1985 ◽  
Vol 43 ◽  
pp. 268-269
Author(s):  
J.Y. Lee
Keyword(s):  
Nucleation And Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Polycrystalline Aluminum ◽  
Axis Orientation ◽  
Temperature Oxidation ◽  
Aluminum Oxidation ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Argon Ion

In the oxidation of metals and alloys, microstructural features at the atomic level play an important role in the nucleation and growth of the oxide, but little is known about the atomic mechanisms of high temperature oxidation. The present paper describes current progress on crystallographic aspects of aluminum oxidation. The 99.999% pure, polycrystalline aluminum was chemically polished and oxidized in 1 atm air at either 550°C or 600°C for times from 0.5 hr to 4 weeks. Cross-sectional specimens were prepared by forming a sandwich with epoxy, followed by mechanical polishing and then argon ion milling. High resolution images were recorded in a <110>oxide zone-axis orientation with a JE0L JEM 200CX microscope operated at 200 keV.

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