Study of Isothermal Oxidation Behavior of FGH91 Superalloy

2015 ◽  
Vol 816 ◽  
pp. 628-633 ◽  
Author(s):  
Zi Chao Peng ◽  
Guo Jun Ma ◽  
Xu Qing Wang ◽  
Xue Jun Luo
Keyword(s):  
Activation Energy ◽  
Titanium Nitride ◽  
Outer Layer ◽  
Oxidation Kinetics ◽  
Intermediate Layer ◽  
Oxidation Behavior ◽  
Matrix Alloy ◽  
Isothermal Oxidation ◽  
Free Layer ◽  
Parabolic Law

Oxidation behavior of FGH91 superalloy in air and the temperature range of 540 to 980 °C for period up to 100h has been studied. The results indicate that oxidation kinetics obeyed parabolic law, and the activation energy of oxidation was calculated to be 98.2 KJ/mol. The scales on the surface were determined by SEM, EDS and XRD, the results show that the oxidation scales were composed of three layers: the outer layer was composed of Cr2O3 layer with a small amount of TiO and NiCr2O4 spinel; the intermediate layer was made up of Al2O3 and matrix alloy; and a small amount of titanium-nitride disperse in the inner layer. Besides, γ’-free layer was formed under the oxidation scales due to the impoverishment of Al in this layer, which was induced by the formations of Al2O3.

Isothermal oxidation of bulk Zr2Al3C4 at 500 to 1000 °C in air

2008 ◽  
Vol 23 (2) ◽  
pp. 359-366 ◽  
Author(s):  
L.F. He ◽  
Z.J. Lin ◽  
Y.W. Bao ◽  
M.S. Li ◽  
J.Y. Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Raman Spectra ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Oxygen Affinity ◽  
Isothermal Oxidation ◽  
Oxide Scales ◽  
X Ray Diffraction ◽  
X Ray ◽  
Parabolic Law

The isothermal oxidation behavior of Zr2Al3C4 in the temperature range of 500 to 1000 °C for 20 h in air has been investigated. The oxidation kinetics follow a parabolic law at 600 to 800 °C and a linear law at higher temperatures. The activation energy is determined to be 167.4 and 201.2 kJ/mol at parabolic and linear stages, respectively. The oxide scales have a monolayer structure, which is a mixture of ZrO2 and Al2O3. As indicated by x-ray diffraction and Raman spectra, the scales formed at 500 to 700 °C are amorphous, and at higher temperatures are α-Al2O3 and t-ZrO2 nanocrystallites. The nonselective oxidation of Zr2Al3C4 can be attributed to the strong coupling between Al3C2 units and ZrC blocks in its structure, and the close oxygen affinity of Zr and Al.

scholarly journals Oxidation Behavior of Quaternary Co-20Re-25Cr-3Si Alloy at Laboratory Air

2021 ◽  
Vol 8 ◽  
Author(s):  
Mingfeng Liu ◽  
Junhuai Xiang ◽  
Hua Wei ◽  
Xiuhong Pan ◽  
Xunhu Xu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Oxidation Resistance ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Pure Oxygen ◽  
Mild Oxidation ◽  
Good Oxidation Resistance ◽  
Catastrophic Oxidation ◽  
Continuous Layer ◽  
Parabolic Law

The iso-thermal oxidation of the quaternary Co-20Re-25Cr-3Si alloy at 1,000–1,200 C under laboratory air for 24 h has been studied. The oxidation kinetics at 1,000–1,200 C follow parabolic law perfectly and the value of oxidation activation energy is 220.74 kJ/mol. Unlike the experimental condition of 0.1 MPa pure oxygen, under laboratory air Co-20Re-25Cr-3Si alloy presents a good oxidation resistance due to the formation of a dense and continuous layer of Cr2O3 in contact with the alloy. A 79% drop in oxygen pressure has changed the oxidation mode from catastrophic oxidation to mild oxidation. The thickness of the protective Cr2O3 layer decreases when temperature increases. Therefore, Co-20Re-25Cr-3Si alloy shows the best oxidation resistance at 1,000 C. Moreover, from another perspective, compared with Co-17Re-23Cr-3Si alloy, the addition of about 2% Cr can also improve the oxidation resistance of the alloy greatly by forming the protective Cr2O3 layer.

Isothermal Oxidation Behavior of FGH720Li Superalloy at Service Temperatures

2021 ◽  
Vol 1035 ◽  
pp. 96-101
Author(s):  
Yue Tang ◽  
Zi Chao Peng ◽  
Xu Qing Wang ◽  
Guo Jun Ma ◽  
Dan Wu
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Elemental Distribution ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Parabolic Law ◽  
Medium Layer ◽  
Oxidation Layers

The oxidation behavior of FGH720Li(P/M Udimet720Li) superalloy was investigated under static atmosphere in temperature ranging from 600°C to 730°C. The oxidation kinetics, composition and morphology of the oxidation layers were characterized by means of isothermal oxidation tests, X-ray diffraction(XRD), scanning electron microscopy（SEM）and energy dispersive X-ray spectroscopy(EDS). The results showed that the oxidation kinetics curves of FGH720Li superalloy followed the parabolic law. The results of cross-sectional morphology and elemental distribution indicated that the oxidation layer could be divided into three parts：porous Cr2O3 outer layer, dense Cr2O3 medium layer and oxidation affected zone with nail-like Al2O3 inner layer. The oxidation process was primarily controlled by the diffusion of chromium and oxygen through the oxide scale.

Isothermal Oxidation Behavior of a New Directionally Solidified Ni-Base Superalloy in Air at Different Temperature

2010 ◽  
Vol 654-656 ◽  
pp. 538-541
Author(s):  
Lei Wang ◽  
Yan Huang ◽  
Zhuo Zhao ◽  
Yang Liu ◽  
Jian Tao Wu ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Oxidation Behaviour ◽  
Diffusion Activation Energy ◽  
Directionally Solidified ◽  
Temperature Range ◽  
Parabolic Law ◽  
Diffusion Activation ◽  
Base Superalloy

The isothermal oxidation behaviour under static atmosphere of a new directionally solidified Ni-base superalloy was investigated. The results showed that the oxidation kinetics curves of the alloy follow parabolic law in the temperature range of 750-950°C. The diffusion activation energy Q is to be about 244.86 kJ•mol-1 and the oxidation within this temperature range is mainly controlled by Cr3+ diffusion among Cr2O3 oxidation film. The oxidation resistance grade of the alloy is perfect anti-oxidation within 750-850°C, and anti-oxidation within 900-950°C. The oxidation film can be divided into TiO2, Cr2O3+TiTaO4+NiCr2O4, Al2O3 and TiN layers, from the surface to inside. Priority oxidation and the inside oxidation of Al are considered with the oxidation of Ti and the depletion of Cr, and it is the key point for the improving of oxidation resistance.

Air Oxidation Behavior of Two Ti-Base Alloys Synthesized by HIP

2016 ◽  
Vol 35 (4) ◽  
pp. 353-359
Author(s):  
S. Liu ◽  
Q. Q. Guo ◽  
L. L. Liu ◽  
L. Xu ◽  
Y. Y. Liu
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Hot Isostatic Pressing ◽  
Air Oxidation ◽  
Isostatic Pressing ◽  
Parabolic Law ◽  
Cast Alloys ◽  
Ternary Additions ◽  
Kinetics Of

AbstractThe oxidation behavior of Ti-5Al-2.5Sn and Ti-6Al-4V produced by hot isostatic pressing (HIP) has been studied at 650–850°C in air for 24 h. The oxidation kinetics of both alloys followed the parabolic law with good approximation, except for Ti-5Al-2.5Sn oxidized at 850°C. Multi-layered scales formed on both alloys at 750°C and 850°C. Ternary additions of Sn and V accounted for the different morphology of the scales formed on these two alloys. In addition, the oxidation behavior of HIP alloys is compared with that of the corresponding cast alloys and the scaling mechanism is discussed.

Isothermal Oxidation Behavior of Ni Base Superalloy DM02 for High Temperature Dies

2007 ◽  
Vol 546-549 ◽  
pp. 1253-1256
Author(s):  
Qing Li ◽  
Jin Xia Song ◽  
Cheng Bo Xiao ◽  
Shi Yu Qu ◽  
Ding Gang Wang ◽  
...  
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Growth Mechanism ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Good Oxidation Resistance ◽  
Base Superalloy

The isothermal oxidation behavior of a new developed Ni base superalloy named DM02 for high temperature dies was studied in this paper. The dynamic curve was achieved by monitoring weight gain of the alloy as a function of time. The results showed that the alloy had fairly good oxidation resistance at 1050°C and 1100°C. The oxidation kinetics at both 1050°C and 1100°C followed parabolic rules in segment. It has been found that the oxidation of the alloy was controlled by multi-oxides of (Ni, Co)O, (Ni, Co)Al2O4, and NiWO4, growth mechanism in the primary stage, and by Al2O3, NiAl2O4 growth mechanism in the following stage. After oxidation at 1050°C for 100h, the oxide scale of the alloy was mainly composed of two areas. Some were thin uniform (Ni， Co)Al2O4(outer)/Al2O3 (inner) composites scale and others were multi-layer oxide scale of ( Ni,Co)O / multi-oxides (mainly NiWO4、NiO and NiAl2O4.) /Al2O3.

Isothermal Oxidation Behavior of the AISI430 Stainless Steel at High Temperature in Static Air

2011 ◽  
Vol 306-307 ◽  
pp. 95-99
Author(s):  
Bin Sun ◽  
Shou Ren Wang ◽  
Yan Jun Wang ◽  
Yong Zhi Pan
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Outer Layer ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chromium Spinel ◽  
Anomalous Oxidation

Isothermal oxidation behavior of the AISI430 stainless steel was investigated at 900°C and 950°C in air. Isothermal themogravimettric analyses were performed at high-temperature for 360ks (kilo-seconds). The microstructures of the oxide films on the stainless steel were characterized by SEM and chemical analyses were performed by EDS and X-ray diffraction. The oxide film included outer layer and inner one. The outer layer was magnetite and hematite oxides with no significant amounts of chromium and the inner one was formed by iron and chromium spinel. Significantly accelerated and anomalous oxidation was observed with the stainless steel AISI430 in air at 900°C.

Isothermal Oxidation Resistance of Zr3[Al(Si)]4C6-Based Composite Ceramics at 1000-1300°C in Air

2018 ◽  
Vol 281 ◽  
pp. 444-449 ◽  
Author(s):  
Lei Yu ◽  
Hui Liu ◽  
Kai Liang ◽  
Zhen Di Zang ◽  
Jia Cheng Shi ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Oxide Thickness ◽  
Unit Surface Area ◽  
Composite Ceramics ◽  
Oxidation Rate Constant ◽  
Parabolic Law ◽  
Unit Surface ◽  
Kinetics Of

The isothermal oxidation behavior of Zr3[Al(Si)]4C6-ZrB2-ZrC composite ceramics at 1000-1300 °C in air has been investigated. The oxidation kinetics of the composites and generally follows a parabolic law. At the same oxidation temperature and time, the weight gain per unit surface area, oxidation rate constant and oxide thickness of the composites are higher than those of monolithic Zr3[Al(Si)]4C6 ceramic. With the incorporation of ZrB2 and ZrC, the oxidation resistance of the composites becomes poor. The surfaces of the oxide layer have a loose and porous structure, consisting of mainly ZrO2 and little mullite, and there are no dense oxide films preventing the inward diffusion of oxygen element effectively.

scholarly journals Oxidation Behavior of Zr-based Amorphous Alloys at 400˚- 450˚C in Air

2019 ◽  
Vol 6 (1) ◽  
pp. 24
Author(s):  
Triwikantoro Triwikantoro ◽  
Romdhoni Graha Pribadi ◽  
Fatimatul Munawaroh
Keyword(s):  
Crystallization Temperature ◽  
Amorphous Alloys ◽  
Oxidation Behavior ◽  
Intermetallic Phase ◽  
Isothermal Oxidation ◽  
Thermo Gravimetric ◽  
Parabolic Law ◽  
Thermo Gravimetric Analyzer ◽  
Kinetics Of ◽  
Dominant Phase

<em><span lang="EN-US">The study of oxidation behavior of amorphous alloys based on Zirconium with 2 variations in composition was carried out: Zr<sub>64.5</sub>Cu<sub>17</sub>Ni<sub>11</sub>Al<sub>7.5 </sub>and Zr<sub>69.5</sub>Cu<sub>12</sub>Ni<sub>11</sub>Al<sub>7.5 </sub>at temperatures of 400 - 450˚C in air. Amorphous Zr-based alloys were thermally characterized using Differential Scanning Calorimeter (DSC) to determine the crystallization temperature and glass transition temperature. The oxidation characterization was carried out using a Thermo gravimetric Analyzer (TGA) at temperatures of 400, 425, and 450˚C for 4 hours in air. The phase analysis of the oxidation product was identified using X-Ra</span><span>y Diffaction</span><span lang="EN-US"> (XRD). Based on DSC data the crystallization temperature for Zr<sub>64.5</sub>Cu<sub>17</sub>Ni<sub>11</sub>Al<sub>7.5</sub> and Zr<sub>69.5</sub>Cu<sub>12</sub>Ni<sub>11</sub>Al<sub>7.5 </sub>is 426 and 442˚C respectively. The oxidation kinetics of the two alloys follow parabolic law and the oxidation rate increases with the addition of temperature. Oxides formed during isothermal oxidation in the Zr<sub>64.5</sub>Cu<sub>17</sub>Ni<sub>11</sub>Al<sub>7.5 </sub>and Zr<sub>69.5</sub>Cu<sub>12</sub>Ni<sub>11</sub>Al<sub>7.5</sub> alloys are t-ZrO<sub>2</sub> (tetragonal) as the dominant phase and ZrO<sub>2</sub> (monoclinic) and CuO as the minor phase. The intermetallic phase is also formed in both samples, t-Zr<sub>2</sub>Ni and Zr<sub>2</sub>Cu.</span></em>

Isothermal oxidation kinetics and oxidation behavior of nickel slag

2020 ◽  
Vol 117 (6) ◽  
pp. 603
Author(s):  
Xiaoming Li ◽  
Xinyi Zhang ◽  
Yi Li ◽  
Xiangdong Xing
Keyword(s):  
Activation Energy ◽  
Oxidation Behavior ◽  
Model Fitting ◽  
Three Dimensional ◽  
Oxidation Kinetic ◽  
Isothermal Oxidation ◽  
Model Free ◽  
Random Nucleation ◽  
Higher Temperature ◽  
Lower Temperature

To improve the reduction effect of nickel slag in preparing Fe–Co–Ni–Cu alloy, an oxidization pretreatment was carried out to changing the structure and phase of silicate and sulfide for the nickel slag before the reducing process. The oxidation behavior and kinetics of nickel slag under different temperature and time conditions were discussed. The results shown that in the oxidation process of nickel slag, the part of Fe2SiO4 was oxidized to Fe3O4 and further to Fe2O3, and the other part of Fe2SiO4 directly oxidized to Fe2O3. Meanwhile, the nickel, cobalt and copper in the form of silicate and sulfide were changed into oxides. The changes of the phases are beneficial to the subsequent reduction of nickel slag. The oxidation degree of nickel slag reached 98% under suitable oxidation conditions (900 °C, 15 min). The oxidation kinetic model of nickel slag obtained by Ln–Ln analysis and Model-fitting method was three-dimensional diffusion at lower temperature (300 °C, 400 °C and 500 °C) and random nucleation at higher temperature (700 °C, 900 °C and 1000 °C) respectively. The activation energies obtained by the model method and the model-free method were 28.58 kJ.mol−1 and 26.28 kJ.mol−1 at lower temperature (300 °C, 400 °C and 500 °C) respectively, and the corresponding value were 81.98 kJ.mol−1 and 78.36 kJ.mol−1 at higher temperature (700 °C, 900 °C and 1000 °C) respectively. The activation energy calculated by the two methods was relatively close, and both can be used to calculate the activation energy.

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