Protection of Orthorhombic Alloy by AlCrN Coating

2016 ◽  
Vol 687 ◽  
pp. 87-91
Author(s):  
Joanna Małecka
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Air Oxidation ◽  
Major Oxide ◽  
Oxidation In Air ◽  
Orthorhombic Alloy ◽  
Poor Oxidation Resistance

The oxidation behavior of AlCrN coating deposited on Ti-25Al-12.5Nb-6Mo-0.48V alloy was investigated at 700 °C and 800 °C in static air. Oxidation in air indicated that the uncoated alloy exhibited poor oxidation resistance due to the formation of TiO2 scale, but the major oxide in the oxidized coating was chromia and alumina and the TiN layers were also observed beneath the coating. No sign of degradation and no scaling of the coating was observed after oxidation.

scholarly journals Oxidation Resistance of Gas Turbine Combustion Materials

1985 ◽  
Author(s):  
M. F. Rothman
Keyword(s):  
Weight Loss ◽  
Gas Turbine ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Carbon Deposition ◽  
Air Oxidation ◽  
Gas Turbine Combustor ◽  
Temperature Range ◽  
Fuel Ratio ◽  
Gas Turbine Combustion

The oxidation behavior of five different gas turbine combustor alloy materials has been characterized in both combustion burner rig environments and in flowing air. The alloys are compared in terms of resistance to weight loss, or thinning, and also in terms of resistance to subsurface internal attack. Burner rig exposures were performed at 1095°C (2000°F) for 100, 200 and 300 hours under combustion conditions involving an air to fuel ratio of about 50:1. Results are also presented for similar exposures where the burner rig air lines were unintentionally plugged-up, yielding a low air:fuel ratio and severe carbon deposition on the samples. In addition to the burner rig studies, results are presented for 1008 hour flowing-air oxidation exposures over the temperature range from 980°C (1800°F) to 1205°C (2200°F).

TEM Observation of the Initial Stage Oxidation of TiAl Based Alloys in a Simulated Combustion Atmosphere

2006 ◽  
Vol 522-523 ◽  
pp. 609-616
Author(s):  
Michiko Yoshihara ◽  
Shigeji Taniguchi ◽  
X.Y. Li
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Combustion Gas ◽  
Test Gas ◽  
Al Content ◽  
Initial Stage ◽  
Combustion Atmosphere ◽  
Bcc Phase ◽  
Poor Oxidation Resistance ◽  
Better Than

The oxidation behavior of Ti-48Al-2Cr-2Nb, Ti-48Al-2Cr-2W and Ti-48Al-2Cr-2Fe was studied in a simulated combustion gas, 10O2-7CO2-6H2O-bal.N2 (vol%), at 1173 K and TEM observation was performed for understanding the initial stage of oxidation behavior. Ti-48Al-2Cr-2Nb and Ti-48Al-2Cr-2W show excellent oxidation resistance in the test gas by forming thin and protective Al2O3-rich scales, while Ti-48Al-2Cr-2Fe shows poor oxidation resistance. The superior oxidation resistance of W-containing alloy is explained in terms of the formation of a bcc phase with low Al content in the alloy which was confirmed by TEM observation and also possible enhanced Al diffusion from the substrate to the scale in this phase. The oxidation resistance of the former two alloys in the test gas is better than in laboratory air, due to the lower O2 content in the test gas. The presence of H2O and CO2 in the test gas enhances the oxidation of Ti-50Al, while it has almost no influence on the oxidation behavior of these two alloys, indicating that these gases are influential to a TiO2-rich scale but not to Al2O3-rich scales.

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.

scholarly journals Microstructure and Oxidation Behavior of Nb-Si-Based Alloys for Ultrahigh Temperature Applications: A Comprehensive Review

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1373
Author(s):  
Fuqiang Shen ◽  
Yingyi Zhang ◽  
Laihao Yu ◽  
Tao Fu ◽  
Jie Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Reaction ◽  
Oxidation Behavior ◽  
Niobium Alloys ◽  
Comprehensive Review ◽  
The Poor ◽  
High Temperature Structural Material ◽  
Ultrahigh Temperature ◽  
Poor Oxidation Resistance

Nb-Si-based superalloys are considered as the most promising high-temperature structural material to replace the Ni-based superalloys. Unfortunately, the poor oxidation resistance is still a major obstacle to the application of Nb-Si-based alloys. Alloying is a promising method to overcome this problem. In this work, the effects of Hf, Cr, Zr, B, and V on the oxidation resistance of Nb-Si-based superalloys were discussed. Furthermore, the microstructure, phase composition, and oxidation characteristics of Nb-Si series alloys were analyzed. The oxidation reaction and failure mechanism of Nb-Si-based alloys were summarized. The significance of this work is to provide some references for further research on high-temperature niobium alloys.

A Novel Electrodeposited Ni-Cr-Al Nanocomposite with Improved Oxidation Resistance

2012 ◽  
Vol 472-475 ◽  
pp. 137-140 ◽  
Author(s):  
Xiu Ying Yang ◽  
Xiao Peng ◽  
Fu Hui Wang
Keyword(s):  
Oxidation Resistance ◽  
Selective Oxidation ◽  
Oxidation Behavior ◽  
Unique Structure ◽  
Al Nanoparticles ◽  
Oxidation In Air

A novel Ni-3Cr-10Al nanocomposite (wt.% ) was fabricated by co-electrodeposition of Ni matrix with Cr and Al nanoparticles. Oxidation in air at 900 oC showed that the Ni-3Cr-10Al nanocomposite compared with the alloy showed good oxidation behavior due to the selective oxidation of Al favored by its unique structure.

Phase Equilibria and Oxidation Behavior of C40 Disilicides in the Nb-Cr-Si System

2015 ◽  
Vol 1760 ◽  
Author(s):  
Nobuaki Sekido ◽  
Ryoma Aizawa ◽  
Shunkichi Ueno
Keyword(s):  
Crystal Structure ◽  
Phase Equilibrium ◽  
Ternary System ◽  
Phase Equilibria ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Phase Boundaries ◽  
Compositional Homogeneity ◽  
Poor Oxidation Resistance

ABSTRACTThe phase equilibrium and oxidation behavior of the disilicides that form in the Nb-Cr-Si ternary system have been investigated. Although NbSi2 and CrSi2 both exhibit a C40 crystal structure, they form separate ranges of compositional homogeneity in the ternary system. Their phase boundaries at 1300 °C have been experimentally determined in this study. The binary NbSi2 exhibited poor oxidation resistance, showing pest-like behavior during oxidation at temperature above 800 °C. In contrast, the alloys containing Cr showed much better oxidation resistance up to 1200 °C.

Development and Oxidation of RexOy-Modified Aluminide Coating

2010 ◽  
Vol 142 ◽  
pp. 274-278 ◽  
Author(s):  
Jing Chong Zhang ◽  
Yue Bo Zhou
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Aluminide Coating ◽  
Composite Films ◽  
Pack Cementation ◽  
Reactive Element ◽  
Aluminide Coatings ◽  
Subsequent Step ◽  
Oxidation In Air

Reactive reactive element oxide RexOy (Re=Ce, Y)-modified aluminide coatings have been developed by the first step of co-electrodeposition of Ni with CeO2 or Y2O3 particls on pure Ni and the subsequent step of diffusional aluminizing on electrodeposited Ni-CeO2/or Y2O3 composite films using pack cementation method at 1100OC for 4 hr. By comparison, aluminizing was also performed with the same condition on an as-deposited Ni film without RexOy particles. The oxidation in air at 900OC indicated that the RexOy (Re=Ce, Y)-modified aluminide coatings were profoundly oxidation resistance as compared to the RexOy (Re=Ce, Y)-free coatings. The effect of CeO2 or Y2O3 on the oxidation behavior is discussed in detail.

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.

Oxidation Behaviors of Pure Ti Thermal Plasma Spray Coated Mo-Si-B Alloys

2011 ◽  
Vol 695 ◽  
pp. 365-368 ◽  
Author(s):  
Young Ho Song ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Seong Hoon Yi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Alloy System ◽  
Underlying Mechanism ◽  
High Temperature Strength ◽  
Air Atmosphere ◽  
Elemental Component ◽  
Ti Powder ◽  
Poor Oxidation Resistance ◽  
Oxidation Behaviors

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. The unstable MoO3 phase is naturally produced when the alloys were exposed at low and /or high temperature in an air atmosphere. In order to resolve the poor oxidation resistance of the alloy system, several attempts have been made via surface coatings and/or component additions. In this study, the oxidation behaviors of the Ti powder thermal spray coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of precursor Ti coatings on Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the Ti powder was tightly bonded and reacted with the surface of the substrate, and TiO2 layer was formed at the outer surface of the coated Ti layer as a result of oxidation exposure. The oxidation behaviors of pure elemental component coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

scholarly journals Rare Earth Elements Enhanced the Oxidation Resistance of Mo-Si-Based Alloys for High Temperature Application: A Review

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1144
Author(s):  
Laihao Yu ◽  
Yingyi Zhang ◽  
Tao Fu ◽  
Jie Wang ◽  
Kunkun Cui ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Rare Earth Elements ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Strengthening Mechanism ◽  
Advanced Materials ◽  
Performance Requirements ◽  
Large Numbers ◽  
The One

Traditional refractory materials such as nickel-based superalloys have been gradually unable to meet the performance requirements of advanced materials. The Mo-Si-based alloy, as a new type of high temperature structural material, has entered the vision of researchers due to its charming high temperature performance characteristics. However, its easy oxidation and even “pesting oxidation” at medium temperatures limit its further applications. In order to solve this problem, researchers have conducted large numbers of experiments and made breakthrough achievements. Based on these research results, the effects of rare earth elements like La, Hf, Ce and Y on the microstructure and oxidation behavior of Mo-Si-based alloys were systematically reviewed in the current work. Meanwhile, this paper also provided an analysis about the strengthening mechanism of rare earth elements on the oxidation behavior for Mo-Si-based alloys after discussing the oxidation process. It is shown that adding rare earth elements, on the one hand, can optimize the microstructure of the alloy, thus promoting the rapid formation of protective SiO2 scale. On the other hand, it can act as a diffusion barrier by producing stable rare earth oxides or additional protective films, which significantly enhances the oxidation resistance of the alloy. Furthermore, the research focus about the oxidation protection of Mo-Si-based alloys in the future was prospected to expand the application field.

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