scholarly journals Effect of γ′ Phase Elements on Oxidation Behavior of Nanocrystalline Coatings at 1050 °C

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 202
Author(s):  
Jinlong Wang ◽  
Lanlan Yang ◽  
Shasha Yang ◽  
Yixuan Jia ◽  
Minghui Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Magnetron Sputtering ◽  
Oxide Scale ◽  
Oxidation Behavior ◽  
Titanium Oxides ◽  
Al2o3 Scale ◽  
Nanocrystalline Coating ◽  
Substrate Alloy

To study the effect of γ′ phase elements on the oxidation behavior of nanocrystalline coatings, two comparable nanocrystalline coating systems were established and prepared by magnetron sputtering. The oxidation experiments of the nanocrystalline coatings on the K38G and N5 superalloys were carried at 1050 °C for 100 h, respectively. The chemical composition of the above coatings is the same as the substrate alloy, including the γ′ elements, such as Al, Ta, and Ti. After serving at a high temperature for certain periods, their oxides participated and then affected the oxidation behavior of the coatings. The Al2O3 scale can be formed on the N5 coating, which cannot be formed on the K38G coating. Tantalum and titanium oxides can be detected on the oxide scale, which ruin its purity and integrity.

Oxidation Behavior of Mo Containing Alloys

2008 ◽  
Vol 595-598 ◽  
pp. 959-966 ◽  
Author(s):  
Esra Dokumacı ◽  
Bulent Önay
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Behavior ◽  
Melting Furnace ◽  
Oxidation Products ◽  
Protective Oxide ◽  
High Temperature Furnace ◽  
Negative Effect ◽  
Backscattered Electron ◽  
Protective Environment

In this study, high temperature (T>500oC) oxidation behavior of two commercial Ni-base alloys and two experimental alloys, all containing more than 10% Molybdenum, is investigated. Experimental alloys were prepared from high purity materials using an arc-melting furnace under a protective environment. During tests, samples were exposed to the stagnant air environment of a high temperature furnace for predetermined times. Extent of oxidation was determined from sample mass change measurements as well as morphological and chemical analyses of the oxidation products. For analyses, a scanning electron microscope (SEM) equipped with backscattered electron (BE) and energy dispersive spectroscopic (EDS) detectors was used. Crystalline phases formed in the product scales over the alloy samples were identified by an x-ray diffractometer (XRD). Preliminary results indicate that although Mo in the alloy prevents the development of a protective oxide scale at the alloy surface, presence of alloying elements such as Cr or Al can decrease this negative effect of Mo on oxide scale formation.

scholarly journals Investigation on Oxidation Behavior of Super304H and HR3C Steel in High Temperature Steam from a 1000 MW Ultra-Supercritical Coal-Fired Boiler

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 521
Author(s):  
Jingjing Li ◽  
Haidong Ma ◽  
Yungang Wang ◽  
Min Xue ◽  
Qinxin Zhao
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Outer Layer ◽  
Oxidation Product ◽  
Oxidation Behavior ◽  
Product Layer ◽  
Two Samples ◽  
High Temperature Steam

Oxidation behavior of Super304H and HR3C steel in high temperature steam from an ultra-supercritical coal-fired boiler was investigated in this paper. The results showed that the steam oxidized surface of Super304H ware composed of Fe2O3, Cr2O3 and FeCr2O4, the oxide scale had a thickness of 50–70 μm. In addition, the steam oxidized surface of HR3C ware composed of Fe2O3, the oxide scale was about 20μm in thickness and contained few pitting. The oxidation product layer of the two samples could be divided into two layers, including outer layer enriched O element and Fe element, and inner layer enriched O element and Cr element. Furthermore, oxide scale spalling was observed on the surface of Super304H sample.

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.

scholarly journals High Temperature Oxidation Behavior of Selective Laser Melting Manufactured IN 625

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 668 ◽  
Author(s):  
Mihaela Raluca Condruz ◽  
Gheorghe Matache ◽  
Alexandru Paraschiv ◽  
Teodor Badea ◽  
Viorel Badilita
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Selective Laser Melting ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Complex Oxide ◽  
Mass Gain ◽  
Laser Melting ◽  
Temperature Oxidation ◽  
High Temperature Oxidation Behavior

The high-temperature oxidation behavior of selective laser melting (SLM) manufactured IN 625 was studied over 96 h of exposure at 900 °C and 1050 °C in air. An extensive analysis was performed to characterize the oxide scale formed and its evolution during the 96 h, including mass gain analysis, EDS, XRD, and morphological analysis of the oxide scale. The mass gain rate of the bare material increases rapidly during the first 8 h of temperature holding and diminishes at higher holding periods for both oxidation temperatures. High-temperature exposure for short periods (24 h) follows a parabolic law and promotes the precipitation of δ phase, Ni-rich intermetallics, and carbides. Within the first 24 h of exposure at 900 °C, a Cr2O3 and a (Ni, Fe)Cr2O4 spinel scale were formed, while at a higher temperature, a more complex oxide was registered, consisting of (Ni, Fe)Cr2O4, Cr2O3, and rutile-type oxides. Prolonged exposure of IN 625 at 900 °C induces the preservation of the Cr2O3 scale and the dissolution of carbides. Other phases and intermetallics, such as γ, δ phases, and MoNi4 are still present. The exposure for 96 h at 1050 °C led to the dissolution of all intermetallics, while the same complex oxide scale was formed.

scholarly journals Studies on the Oxidation Behavior of a Designed Nanocrystalline Coating on K38 Alloy at 1050 °C

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1188
Author(s):  
Jinlong Wang ◽  
Bo Meng ◽  
Wenyao Sun ◽  
Lanlan Yang ◽  
Minghui Chen ◽  
...  
Keyword(s):  
Oxidation Behavior ◽  
Coating System ◽  
Nanocrystalline Coating ◽  
2Nd Generation ◽  
Topologically Close Packed ◽  
Significant Difference ◽  
Oxidation Performance ◽  
Substrate Alloy ◽  
New Framework

A new framework for a nanocrystalline coating system is established and prepared to study the oxidation behavior with a significant difference in elemental composition. K38 superalloy is selected as a substrate alloy and the composition of the 2nd-generation single-crystal superalloy Rene N5 is used as the sputtered nanocrystalline coating. The oxidation behavior of the newly designed nanocrystalline coating is comparatively studied with the original K38 coating and its substrate alloy at 1050 °C for 500 h. Moreover, microstructure evolution on the interface is used for studying the influence of element interdiffusion behavior on the substrate alloy. Results show that the nanocrystalline coatings increase the oxidation performance of alloys at 1050 °C for 100 h. The sputtered SN-N5 nanocrystalline coating exhibits the best oxidation resistance among the three groups of specimens for 500 h. Interdiffusion occurred and is observed on the SN-N5 coating after long-term oxidation. However, no topologically close-packed phases participated in the substrate alloy.

Al-21Ti-23Cr High-Temperature Protective Coating on TiAl Intermetallic Compounds by RF Magnetron Sputtering

1996 ◽  
Vol 460 ◽  
Author(s):  
J. Y. Park ◽  
H. N. Lee ◽  
S. W. Park ◽  
M. H. Oh ◽  
D. M. Wee
Keyword(s):  
High Temperature ◽  
Magnetron Sputtering ◽  
Tensile Test ◽  
Protective Coating ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Tensile Deformation ◽  
Rf Magnetron Sputtering ◽  
Deformation Properties ◽  
Before And After

ABSTRACTTi-48A1 specimens were coated with Al-21Ti-23Cr film at 200 W, 0.8 Pa and 573 K by RF magnetron sputtering. The oxidation behavior of the coated specimens was investigated through isothermal and cyclic oxidation tests, and the tensile deformation properties of the coated specimens were also investigated before and after oxidation. The isothermal and cyclic oxidation curves showed that the Al-21Ti-23Cr film was very effective in decreasing the oxidation rate of Ti-48A1. This excellent oxidation resistance is attributable to the formation of a protective Al2O3 layer on the surface of the Al-21Ti-23Cr film. It was found from the results of the tensile test that the protective Al2O3 layer on the surface of the Al-21Ti-23Cr film enabled the Ti-48A1 to maintain its tensile properties in an oxidizing environment.

Oxidation behavior of a nanocrystalline coating with low Ta content at high temperature

2021 ◽  
Vol 180 ◽  
pp. 109182
Author(s):  
Lanlan Yang ◽  
Jinlong Wang ◽  
Ruize Yang ◽  
Shasha Yang ◽  
Yixuan Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Behavior ◽  
Nanocrystalline Coating

Effect of Mo on the Oxidation Behavior of NiTiAl Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1481-1484
Author(s):  
Jian Xu ◽  
Xin Qing Zhao ◽  
Sheng Kai Gong
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Oxide Layer ◽  
Oxygen Diffusion ◽  
Oxidation Behavior ◽  
Oxidation Process ◽  
Oxide Scales ◽  
Cross Sectional ◽  
Oxidation Layer ◽  
Poor Adhesion

The effect of Mo on the oxidation behavior of TiNiAl at 1073K has been investigated. It is found that 1at.% Mo addition can increase the diffusion of Al in the alloys and promote the formation of dense and continuous Al-rich oxide layer. Therefore the oxygen diffusion can be effectively impeded and the oxidation behavior of TiNiAl is improved. The observation of the cross-sectional oxidation layer showed that beneath the top oxide scale a Mo-rich oxide layer formed. Because the oxide of Mo is volatile at high temperature, voids formed in the oxide scales during the oxidation process. 3at.% Mo addition could cause cracks between the oxide scale and the substrate, resulting in poor adhesion of the oxide scale to the substrate.

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