scholarly journals Studies on the Oxidation Behavior and Microstructural Evolution of Two Nb-Modified HR3C Austenitic Steels under Pure Water Vapor at 650 °C

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5447
Author(s):  
Jinlong Wang ◽  
Bo Meng ◽  
Jintao Lu ◽  
Yongli Zhou ◽  
Dongxu Yang ◽  
...  
Keyword(s):  
Oxide Scale ◽  
Oxidation Resistance ◽  
Microstructural Evolution ◽  
Oxidation Behavior ◽  
Pure Water ◽  
Austenitic Steels ◽  
Microstructural Stability ◽  
Moderate Amount ◽  
Initial Oxidation ◽  
High Oxidation Resistance

The steam oxidation behavior of three heterogeneous HR3C alloys was investigated at 650 °C comparatively. After a long-term oxidation process for 1000 h, the results demonstrated that the commercial HR3C alloy already exhibited a high oxidation resistance. However, the spallation resistance of the oxide scale was low during the initial oxidation period. The addition of a moderate amount of Nb into the alloy (1#HR3C) increased the oxidation resistance of the alloy. In addition, the improvement of the microstructural stability was substantially influenced by solid solution strengthening and fine grain strengthening. However, the addition of excessive Nb could significantly affect the growth model of the oxide scale and negatively affect the oxidation performance and microstructural evolution of the alloy (2#HR3C).

scholarly journals Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

2021 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Group Iv ◽  
Hypersonic Vehicles ◽  
Metal Carbides ◽  
Initial Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

Effects of Yttrium on Cyclic Oxidation Resistance of Co-10Cr-5Al Alloy at 700 °C

2014 ◽  
Vol 528 ◽  
pp. 25-29
Author(s):  
Ling Yun Bai ◽  
Xian Chao Xu ◽  
Jun Huai Xiang ◽  
Yun Xiang Zheng ◽  
Jun Wang
Keyword(s):  
Oxide Scale ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Adhesive Property ◽  
Complex Mode ◽  
Rate Law ◽  
Parabolic Rate

The cyclic oxidation behavior of Co-10Cr-5Al alloys in atmosphere at 700 °C was investigated. The addition of 0.3 at.% Y changed the oxidation behavior from the approximate parabolic rate law to complex mode. The scale grown on the surface of Co-10Cr-5Al cracked seriously, while the oxide scale the Y doped alloy had better adhesive property. Yttrium doped in the sample promoted the forming of continuous Al2O3layer and decreased the oxidation rate of Co-10Cr-5Al alloys.

Oxide Scale Behavior and its Effect on Oxidation Resistance in Al Alloys Containing Alkaline Earth Metal Elements

2017 ◽  
Vol 380 ◽  
pp. 120-123
Author(s):  
Seong Ho Ha ◽  
Young Ok Yoon ◽  
Nam Seok Kim ◽  
Sung Hwan Lim ◽  
Shae K. Kim
Keyword(s):  
Oxide Scale ◽  
Oxidation Resistance ◽  
Surface Segregation ◽  
Earth Metal ◽  
Mg Alloy ◽  
Initial Oxidation ◽  
Melt Temperature ◽  
Ca Addition ◽  
Constituent Elements ◽  
Scale Behavior

Oxide scale behaviors by surface segregation of Mg, Ca and Be in Al and their effects on oxidation resistance at melt temperature were investigated. With the addition of Ca and Be in Al-7.5mass%Mg alloy, the samples showed a suppressed weight gain. However, in the initial oxidation, Ca added samples exhibited improved oxidation resistance. As a result of oxide layer observation by microscopy, Ca added Al-7.5mass%Mg alloy exhibited the region overlapped by constituent elements, indicating multi-element oxide is formed on the surface. In the oxidation of Al-Mg-Be system, BeO is formed as primary oxide and mixed layer with MgO, while Ca addition in Al-Mg system causes no change in the primary and secondary oxides, but formation of CaMg2Al16O27. BeO and BeAl2O4may contribute to balanced layer by combination between constituent oxides in the Al-Mg-Be system. In the case of Ca addition, CaMg2Al16O27acts as a filler of the cracks in MgO layer.

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.

In Situ Synthesis and Oxidation Behavior of Ti-Al-Ag Ternary Coatings

2016 ◽  
Vol 849 ◽  
pp. 702-708
Author(s):  
Lei Yang ◽  
Hua Li ◽  
He Zhou Liu ◽  
Yang Yang Zhang
Keyword(s):  
Titanium Alloy ◽  
Thermal Treatment ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Plasma Spray ◽  
Oxidation Behavior ◽  
Experimental Results ◽  
Better Than

Mixture powders with different ratio of Ag/γ-TiAl were deposited on titanium alloy by low presure plasma spray and thermal treatment was applied to convert the mixture coatings into Ti-Al-Ag ternary ones. The experimental results indicated that the oxidation resistance of ternary coatings was better than sheer γ-TiAl coating and increased with increasing Ag from 2at.% to 4at.% at 700 and 800°C. The outside oxide scale consisted of alumina and a small amount of rutile due to the insufficient diffusion of Ag in γ-TiAl.

High Temperature Oxidation Behavior of Al Added Mo / Mo5SiB2in-situ Composites

2004 ◽  
Vol 842 ◽  
Author(s):  
Akira Yamauchi ◽  
Kyousuke Yoshimi ◽  
Shuji Hanada
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Mass Gain ◽  
Protective Oxide ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
Temperature Range ◽  
Crystalline Oxides ◽  
Rapid Mass

ABSTRACTIsothermal oxidation behavior of Mo/Mo5SiB2in-situ composites containing small amounts of Al was investigated under an Ar-20%O2 atmosphere in the temperature range of 1073–1673 K. The Mo/Mo5SiB2in-situ composites, (Mo-8.7mol%Si-17.4mol%B)100-xAlx (x=0, 1, 3, and 5mol%), were prepared by Ar arc-melting, and then homogenized at 2073 K for 24 h in an Ar-flow atmosphere. Without addition of Al, Mo/Mo5SiB2in-situ composite exhibits a rapid mass loss at the initial oxidation stage, followed by passive oxidation after the substrate is sealed with borosilicate glass in the temperature range of 1173–1473 K, whereas it exhibits a rapid mass gain around 1073 K. On the other hand, small Al additions, especially of 1 mol%, significantly improve the oxidation resistance of Mo/Mo5SiB2in-situ composites at temperatures from 1073–1573 K. The excellent oxidation resistance is considered to be due to the rapid formation of a continuous, dense scale of Al-Si-O complex oxides. The protective oxide scales contain crystalline oxides, and the amounts of the crystalline oxides obviously increase with Al concentration.

scholarly journals Effect of Cr and Al alloying on the oxidation resistance of a Ti5Si3-incorporated MoSiBTiC alloy

2021 ◽  
Vol 40 (1) ◽  
pp. 204-213
Author(s):  
Xi Nan ◽  
Tomotaka Hatakeyama ◽  
Shuntaro Ida ◽  
Nobuaki Sekido ◽  
Kyosuke Yoshimi
Keyword(s):  
Solid Solution ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Oxide Scales ◽  
Accelerated Oxidation ◽  
Oxidation Test ◽  
Poor Oxidation Resistance

Abstract The effects of adding Cr and Al on the oxidation behavior of a Ti5Si3-incorporated MoSiBTiC alloy (46Mo–28Ti–14Si–6C–6B, at%) were investigated at 800 and 1,100°C. The addition of Cr and Al largely improved the oxidation resistance of the MoSiBTiC alloy at 800°C due to the formation of Cr2(MoO4)3 and Al2(MoO4)3 in the oxide scales. These protective molybdates mainly formed on the molybdenum solid solution (Moss) and Mo3Si phases that show poor oxidation resistance in the Cr- and Al-free alloy and consequently increased the oxidation resistance of the alloys. However, accelerated oxidation occurred on the 10Al alloy after the long-term oxidation test, suggesting that the formed oxide scale has limited protection ability. At 1,100°C, the addition of Cr and Al also enhanced the oxidation resistance to some extent by forming Cr2O3 and Al2O3 in the oxide scales.

Influence of Micro-Structure on Oxidation Behavior of a Ni-Based Superalloy at 1000°C

2008 ◽  
Vol 595-598 ◽  
pp. 87-94 ◽  
Author(s):  
Li Liu ◽  
Ying Li ◽  
Fu Hui Wang
Keyword(s):  
Oxide Scale ◽  
Oxidation Resistance ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Flat Surface ◽  
Cast Alloy ◽  
Oxidation Mechanism ◽  
Micro Structure ◽  
Al2o3 Layer ◽  
Oxidation Behaviors

The isothermal and cyclic oxidation behaviors of a Ni-based superalloy with singlecrystalline (SC), polycrystalline and nanocrystalline (NC) structures were studied at 1000°C. Results indicated that a uniform oxides scale consisted of external Cr2O3 with little TiO2 and internal continuous Al2O3 formed on SC alloy. A non-uniform external oxide of which some locations were nodule-like scale was formed on surface of cast alloy. The nodule-like parts consisted of TiO2, Cr2O3 and serious internal oxidation of Al, and rest flat surface was a Cr2O3 and Al2O3 layer. A continuous Al2O3 layer formed on the sputtered NC coating. The micro-structure influenced the oxidation mechanism and resulted in different oxide scale formed on three materials, which greatly influenced materials’ oxidation and cyclic-oxidation resistance.

Improvement of Oxidation Behavior at 1,073 and 1,173K of Austenitic Stainless Steels by Addition of Ni

2014 ◽  
Vol 931-932 ◽  
pp. 338-343 ◽  
Author(s):  
Ornin Srihakulung ◽  
Panyawat Wangyao ◽  
Gobboon Lothongkum ◽  
Prasonk Sricharoenchai
Keyword(s):  
Growth Rate ◽  
Weight Gain ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Rate Constant ◽  
Stainless Steels ◽  
Oxidation Behavior ◽  
Austenitic Stainless Steels ◽  
Exponential Rate ◽  
Nickel Addition

This work studied the effect of Nickel addition to improve the oxidation behavior of austenitic stainless steels at 1,073 K and 1,173 K. The results show that Nickel increases the oxidation resistance of the austenitic stainless steels. The compositions of oxide scale also change form only Cr2O3 to be Cr2O3, Fe2O3, NiFe2O4 and Ni (Cr2O4). The oxidation behavior follows the parabolic rate law; W = ktn, where W = weight gain (g/cm2), t = time (s), k is the exponential rate constant and n is the exponent of growth rate. The n values are between 0.47-0.88.

Oxidation Resistance of Austenitic Steels under Thermal Shock Conditions in an Environment Containing Water Vapor

2018 ◽  
Vol 37 (4) ◽  
pp. 341-350 ◽  
Author(s):  
Barbara Koscielniak ◽  
Grzegorz Smola ◽  
Zbigniew Grzesik ◽  
Adam Hernas
Keyword(s):  
Water Vapor ◽  
Thermal Shock ◽  
Oxidation Resistance ◽  
Power Plants ◽  
Oxidation Behavior ◽  
Austenitic Steels ◽  
Corrosion Resistant ◽  
Good Oxidation Resistance ◽  
Internal Part ◽  
Oxidation Resistant

AbstractThe oxidation behavior of Super 304 H, Sanicro 25, HR3C and HR6W steels, which are recommended for use in ultra-supercritical power plants, as well as corrosion resistant X2CrNiMo17-12-2 steel was studied in this work. Oxidation tests were carried out under thermal shock conditions in an oxygen-rich environment (containing 50 vol. % water vapor) at a temperature equal to 750 °C. The investigated steels (excluding X2CrNiMo17-12-2 steel) are characterized by good oxidation resistance under thermal shock conditions. A highly protective Cr2O3 layer was formed in the internal part of scales growing on the surfaces of investigated steels. The X2CrNiMo17-12-2 steel has worse oxidation resistant properties than the other grades of steels.

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