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 Exploring the Effect of Silicon on the High Temperature Corrosion of Lean FeCrAl Alloys in Humid Air

2021 ◽  
Author(s):  
T. Sand ◽  
A. Edgren ◽  
C. Geers ◽  
V. Asokan ◽  
J. Eklund ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Oxidation Behavior ◽  
High Temperature Corrosion ◽  
The Other ◽  
Oxide Scales ◽  
Protective Oxide ◽  
New Approach ◽  
Fecral Alloys ◽  
Cr Evaporation

AbstractA new approach to reduce the chromium and aluminium concentrations in FeCrAl alloys without significantly impairing corrosion resistance is to alloy with 1–2 wt.% silicon. This paper investigates the “silicon effect” on oxidation by comparing the oxidation behavior and scale microstructure of two FeCrAl alloys, one alloyed with silicon and the other not, in dry and wet air at 600 °C and 800 °C. Both alloys formed thin protective oxide scales and the Cr-evaporation rates were small. In wet air at 800 °C the Si-alloyed FeCrAl formed an oxide scale containing mullite and tridymite together with α- and γ-alumina. It is suggested that the reported improvement of the corrosion resistance of Al- and Cr-lean FeCrAl’s by silicon alloying is caused by the appearance of Si-rich phases in the scale.

Manganese Effect on Isothermal High Temperature Oxidation Behaviour of AISI 304 Stainless Steel

2008 ◽  
Vol 595-598 ◽  
pp. 1127-1134 ◽  
Author(s):  
Frédéric Riffard ◽  
Henri Buscail ◽  
F. Rabaste ◽  
Eric Caudron ◽  
Régis Cueff ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Oxide Scale ◽  
304 Stainless Steel ◽  
Initial Growth ◽  
Aisi 304 Stainless Steel ◽  
Protective Oxide ◽  
Temperature Oxidation ◽  
Aisi 304

Chromia-forming steels are excellent candidates to resist to high temperature oxidizing atmospheres because they form protective oxide scales. The oxide scale growth mechanisms are studied by exposing AISI 304 stainless steel to high temperature conditions in air, and the analyses were carried out by means of thermogravimetry and in situ X-rays diffraction. The in situ XRD analyses carried out during high temperature AISI 304 steel oxidation in air reveals the accelerated growth of iron-containing oxides such as hematite Fe2O3 and iron-chromite FeCr2O4, when the initial germination of the oxide layer contains the presence of a manganese-containing spinel compound (1000°C). When the initial growth shows the only chromia formation (800°C), hematite formation appears differed in time. Protection against corrosion is thus increased when the initial germination of manganese-containing spinel oxide is inhibited in the oxide scale.

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.

Isothermal Oxidation Behavior of AlN-TiB2 Ceramics Synthesized by SHS-HIP

2013 ◽  
Vol 575-576 ◽  
pp. 170-173
Author(s):  
Li Juan Zhou ◽  
Yun Xia Zhao ◽  
Hong Bo Li ◽  
Yong Ting Zheng ◽  
Fan Tao Meng
Keyword(s):  
High Temperature ◽  
Oxidation Behavior ◽  
Hot Isostatic Pressing ◽  
Isothermal Oxidation ◽  
Oxidation Products ◽  
Aluminum Borate ◽  
Temperature Synthesis ◽  
Good Oxidation Resistance ◽  
High Temperature Synthesis ◽  
Conductive Ceramics

sothermal oxidation behavior of the AlN-TiB2 conductive ceramics prepared by self-propagating high-temperature synthesis and hot isostatic pressing (SHS-HIP) was evaluated in a temperature range from 900 to 1400 °C for exposure times from 1 to 16 h in air. The oxidation experimental results show that the conductive ceramics have a good oxidation resistance below 1200 °C. The oxidation products on the sample surfaces are mainly composed of Al2TiO5, TiO2 and aluminum borate phases.

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