Corrosion Behavior of Incoloy 800 in Molten Nitrate Salt

2014 ◽  
Vol 887-888 ◽  
pp. 357-361
Author(s):  
Yu Jun Zhang ◽  
Lei Lei Xiao ◽  
Jun Hua Liu ◽  
Mei Ling Liu ◽  
Min Hui Fu
Keyword(s):  
Phase Composition ◽  
Corrosion Behavior ◽  
Layer Structure ◽  
Energy Dispersive Spectrometer ◽  
Oxide Films ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Parabolic Law ◽  
Incoloy 800 ◽  
Kinetics Of

The corrosion behavior of Incoloy 800 as the receiver tube materials in a solar tower field exposed to a mixed molten nitrate salts (KNO3: 40wt.%, NaNO3: 60wt%) at 560°C, has been investigated by several methods. After Incoloy 800 specimens were immersed respectively in molten salts at 560°C for different times (5h, 10h, 20h, 30h, 40h, 60h, and 80h), the weight-loss of specimens were test, the morphology of oxide films on the Incoloy 800 specimens were observed by Optical microscope (OM) and Scanning electron microscopy (SEM), the phase composition of the oxide film were investigated by X-ray diffraction (XRD) and Energy dispersive spectrometer (EDS). The experimental results revealed that the corrosion kinetics of the tested alloy agreed with the parabolic law at 560°C, and the corrosion rate is 91.5μm/year. The analysis of the phase composition shows the oxide films had a duplex layer structure with Fe2O3in the outer layer, andγ-(Fe,Ni) and Cr2O3in the inner layer.

scholarly journals The Cyclic Oxidation and Hardness Characteristics of Thermally Exposed Titanium Prepared by Inductive Sintering-Assisted Powder Metallurgy

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 104
Author(s):  
Fahamsyah H. Latief ◽  
El-Sayed M. Sherif ◽  
Agus S. Wismogroho ◽  
Wahyu B. Widayatno ◽  
Hany S. Abdo
Keyword(s):  
Powder Metallurgy ◽  
Single Phase ◽  
Oxide Scales ◽  
Cyclic Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Rates ◽  
Parabolic Law ◽  
Kinetics Of ◽  
Hardness Values

The oxidation and hardness of thermally exposed titanium (Ti) prepared using inductive sintering-assisted powder metallurgy was evaluated through cyclic tests in air at 700–900 °C for 100 h (5 cycles). In general, the oxidation kinetics of the Ti samples followed the parabolic law and their oxidation rates increased with increasing oxidation temperatures. The rutile form of titanium dioxide (TiO2) was detected by X-ray diffraction in the oxide scales after oxidation at 700 °C and 900 °C. Furthermore, the TiO2 grain size and thickness were significantly influenced by an increase in the oxidation temperature. Lastly, the formation of rutile as a single-phase on the surface of oxidized Ti enhanced the hardness of the oxide scales, whereas the substrate had lower hardness values than the oxide scales due to diffusion of Ti atoms at the surface to form the TiO2 oxide scales.

Study on Aging Strengthening of Mg-Zn-Cu Alloy Based on Component Optimization Design

2016 ◽  
Vol 873 ◽  
pp. 33-37
Author(s):  
Jie Ye ◽  
Xiao Ping Lin ◽  
Yun Dong ◽  
Bo Li ◽  
Gao Peng Xu ◽  
...  
Keyword(s):  
Optimization Design ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Strengthening Phase ◽  
X Ray ◽  
Hardness Tester ◽  
Cu Alloy ◽  
Factsage Software ◽  
Kinetics Of ◽  
Zn Alloy

In this study, we investigated the aging strengthening of Mg-Zn-Cu alloy based on component optimization design by FactSage software, optical microscope (OM), X-ray diffraction (XRD) and Vickers hardness tester. The results show that the precipitation rate of MgZn2 phase in Mg-6Zn-1Cu is significantly higher than that of the other alloys. When Mg-6Zn-1Cu alloy is subjected to aging at 160<strong>°C</strong> for different time, the phase consists of α-Mg, MgCu2 and MgZn2. The content of main strengthening phase MgZn2 is increasing with the prolonging of aging time. When Mg-6Zn-1Cu alloy aged at 160<strong>°</strong><strong>C</strong> for 10h, the kinetics of precipitation is considerably accelerated. The results indicate that the hardening produced in the Cu-containing alloy is considerably higher than in the Mg-Zn alloy. Therefore, based on component optimization design to establish Mg-Zn-Cu alloy solidification database, and to predict the phase equilibrium and thermodynamic properties of the alloy, is an effective method for the development of new magnesium alloy.

scholarly journals PHASE COMPOSITION OF OXIDE FILMS FORMED ON THE SURFACE OF THE FE-CR-AL SYSTEM COATINGS

2020 ◽  
pp. 14-18
Author(s):  
V. G. Shmorgun ◽  
A. I. Bogdanov ◽  
O. V. Slautin ◽  
V. P. Kulevich
Keyword(s):  
Phase Composition ◽  
Aluminum Content ◽  
Oxide Films ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Glancing Angle ◽  
Stable Growth ◽  
Metastable Alumina

The phase composition of the oxide films on the surface of the Fe-Cr-Al system coatings is studied using glancing angle X-ray diffraction. It is shown that at 900 °С the formed oxide films consist of αAlO and (FeCr)O, to which FeAlO oxide is added during long-term exposure. An increase in temperature to 1100 °C intensifies the growth of oxide films, and an increase in the aluminum content ensures a stable growth of αAlO and FeAlO oxides. When the aluminum content in the coating is more than 10 at. % at large exposure times, metastable alumina δAlO is formed, the formation of which is associated with a decrease in the concentration of chromium in thin surface layers.

Corrosion Behavior and Mechanism of Heat-Resistant Steel T91 in High-Temperature Carbon Dioxide Environment

2019 ◽  
Vol 944 ◽  
pp. 398-403
Author(s):  
Yong Gui ◽  
Zhi Yuan Liang ◽  
Miao Yu ◽  
Qin Xin Zhao
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Corrosion Behavior ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
X Ray Diffraction ◽  
Heat Resistant Steel ◽  
Scale Thickness ◽  
Corrosion Scale ◽  
Kinetics Of

Corrosion behavior of martensitic heat resisting steel T91 in high-temperature carbon dioxide environment at 500-700 °C was investigated. X-ray diffraction, scanning electron microscopy and glow-discharge optical emission spectrometry were employed to characterize the corrosion products. The results showed that the corrosion kinetics of T91 followed a parabolic law with experimental time. The oxide scale thickness of T91 followed an exponential growth law from 500 °C to 700 °C. Internal carburization was detected underneath the corrosion scale. What’s more, the carburization depth was larger than the corrosion scale. The variations of Cr and C elements distribution were discussed.

TEM AND FESEM ANALYSIS OF DISSIMILAR JOINTS OF INCOLOY 800 HT AND P91 STEEL ON GTAW PROCESS

2019 ◽  
Vol 26 (05) ◽  
pp. 1850190 ◽  
Author(s):  
V. LAKSHMANAN ◽  
P. SATHIYA
Keyword(s):  
Electron Microscopy ◽  
Energy Dispersive Spectrometer ◽  
Welding Process ◽  
Optical Microscope ◽  
Filler Material ◽  
Filler Materials ◽  
Dissimilar Joints ◽  
P91 Steel ◽  
Dissimilar Weld ◽  
Incoloy 800

The present paper investigates the dissimilar joining of Incoloy 800 HT and P91 steel using gas tungsten arc welding process. Welding was carried out using two filler materials, namely, Inconel 82 and 9CrMoV-Nb. Welding speed, current and voltage were considered as input parameters. Microhardness, tensile strength and impact strength were measured as performance characteristics. Metallurgical aspects of dissimilar welds were analyzed on the basis of microstructure obtained by using optical microscope, high-resolution field emission scanning electron microscopy and transmission electron microscopy. The ferrite content was measured by using feritscope, and the elemental analysis was carried out with the help of X-ray energy dispersive spectrometer. It was found that the 9CrMoV-Nb filler material produced dissimilar weld with better mechanical properties than the dissimilar weld produced using Inconel 82 filler material.

Analysis on the Structure and Mechanism of Cracking and Spalling for Super304H Steel Oxide Films in High-Temperature Steam

2014 ◽  
Vol 908 ◽  
pp. 72-76 ◽  
Author(s):  
Yan Hui Li ◽  
Shu Zhong Wang ◽  
Xue Dong Li ◽  
Meng Meng Ren
Keyword(s):  
High Temperature ◽  
Outer Layer ◽  
Layer Structure ◽  
Spinel Phase ◽  
Oxide Films ◽  
Primary Component ◽  
Steel Matrix ◽  
X Ray Diffraction ◽  
High Temperature Steam ◽  
Super304h Steel

In this paper, by means of Scanning Electronic Microscope (SEM), X-ray diffraction analyzer (XRD) and Cross hatch scanning analysis, the Structure and mechanism of cracking and spalling for Super304H steel oxide films in high temperature steam were investigated. With the oxidation proceeding, the surface of Super304H steel specimens is covered by a large amount of tiny holes, which causes the occurrence of an outer oxide layer. The Super304H oxide film generally has a double-layer structure: the outer layer mainly for iron oxide Fe3O4, also being covered by a small amount of Fe2O3, and the inner layer with the FeCr2O4 spinel phase as primary component. Because of the inhomogeneity of oxide distribution, large amounts of smaller gaps appear in the Super304H steel oxide films. Due to the differences among the outer layer, the inner layer and steel matrix in thermal expansion coefficient, when the steam temperature around the specimen changes periodically, the stress variation arise in the Super304H steel and oxide films, which causes the cracking and spalling of oxide films.

scholarly journals Formation of Silicide and Silicide-Aluminide Coatings on Molybdenum Alloy during Slurry Cementation Process: Influence of Slurry Volume

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6940
Author(s):  
Agnieszka Elżbieta Kochmańska ◽  
Aneta Jarlaczyńska ◽  
Jolanta Baranowska
Keyword(s):  
Phase Composition ◽  
Growth Kinetics ◽  
Protective Coatings ◽  
Void Formation ◽  
Molybdenum Alloy ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
X Ray ◽  
Aluminide Coatings ◽  
Kinetics Of

New slurry cementation method was used to produce silicide and silicide-aluminide protective coatings on molybdenum alloy (TZM). The slurry cementation processes were carried out at a temperature of 1000 °C in different time intervals with the use of varied slurry mass values. The microstructure and thickness of the coatings were studied by means of scanning microscopy. Chemical composition using X-ray microanalysis and phase composition using X-ray diffraction were also investigated. Coating microhardness was determined. The obtained coatings had a multilayer structure. Phases from the Al-Si-Mo system were observed in silicide-aluminide coatings and phases from the Si-Mo system were observed in silicide coatings. The microhardness strongly depended on the phase composition of the coating. It was demonstrated that slurry mass values had an important influence on the morphology and growth kinetics of silicide-aluminide coatings. In the case of a small amount of the slurry, the deficiency of alloying elements occurring during long processes reduces growth kinetics and can lead to void formation in the structure of silicide-aluminide coatings.

Study on Atmospheric Corrosion Behaviour of Sicp/Al Composite

2010 ◽  
Vol 136 ◽  
pp. 275-278
Author(s):  
Xian Liang Zhou ◽  
Duo Sheng Li ◽  
Ai Hua Zou ◽  
Xiao Zhen Hua ◽  
G.Z. Ye ◽  
...  
Keyword(s):  
Atmospheric Corrosion ◽  
Corrosion Behaviour ◽  
Energy Dispersive Spectrometer ◽  
Optical Microscope ◽  
Atmospheric Environment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Composite ◽  
Amorphous Al2o3 ◽  
Scanning Electron

SiCp/Al composite was fabricated by the method of pressureless-infiltration. In atmospheric environment, the atmospheric corrosion behavior of SiCp/Al composites (ZL101+49%SiC+5%Mg) was studied by mass loss, optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR), respectivelhy.The results show that the corrosion rate of the SiCp/Al composites increases with increasing of time in atmospheric environment. Pitting corrosion is the main characteristic of SiCp/Al composite, and corrosion area gradually extends around with time increasing. At last, sheet like corrosion substrates distribute in the surface of n the SiCp/Al composites. Amorphous Al2O3 and amorphous AlxSO4yOHz are the main corrosion products.

scholarly journals Formation Mechanism of Aluminide Diffusion Coatings on Ti and Ti-6Al-4V Alloy at the Early Stages of Deposition by Pack Cementation

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3097
Author(s):  
Hailiang Du ◽  
Ning Tan ◽  
Li Fan ◽  
Jiajie Zhuang ◽  
Zhichao Qiu ◽  
...  
Keyword(s):  
Outer Layer ◽  
Aluminide Coating ◽  
Energy Dispersive Spectrometer ◽  
Pack Cementation ◽  
X Ray Diffraction ◽  
Diffusion Coatings ◽  
Early Stages ◽  
Outward Migration ◽  
Kinetics Of ◽  
Precision Balance

The diffusion coatings were deposited on commercially pure Ti and Ti-6Al-4V alloy at up to 1000 °C for up to 10 h using the pack cementation method. The pack powders consisted of 4 wt% Al (Al reservoir) and 4 wt% NH4Cl (activator) which were balanced with Al2O3 (inert filler). The growth kinetics of coatings were gravimetrically measured by a high precision balance. The aluminised specimens were characterised by means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). At the early stages of deposition, a TiO2 (rutile) scale, other than aluminide coating, was developed on both materials at <900 °C. As the experimental temperature arose above 900 °C, the rutile layer became unstable and reduced to the low oxidation state of Ti oxides. When the temperature increased to 1000 °C, the TiO2 scale dissociated almost completely and the aluminide coating began to develop. After a triple-layered coating was generated, the coating growth was governed by the outward migration of Ti species from the substrates and obeyed the parabolic law. The coating formed consisted of an outer layer of Al3Ti, a mid-layer of Al2Ti and an inner layer of AlTi. The outer layer of Al3Ti dominated the thickness of the aluminide coating.

Influence of FeCrAl Coating Arc Sprayed on Aluminum Corrosion Resistance of H13 Steel

2015 ◽  
Vol 817 ◽  
pp. 565-570
Author(s):  
Jian Hua Zhao ◽  
Li Wang ◽  
Zheng Heng Shang
Keyword(s):  
Corrosion Resistance ◽  
Cross Section ◽  
Layer Structure ◽  
Energy Dispersive Spectrometer ◽  
Electric Arc ◽  
Arc Spraying ◽  
X Ray Diffraction ◽  
H13 Steel ◽  
X Ray ◽  
Aluminum Corrosion

FeCrAl coating was prepared on the surface of H13 steel through electric arc spraying (EASP) technology. The surface and cross section morphology, elements and phase composition of the composite coating were analyzed by the means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The aluminum corrosion resistance was tested by the static hot-dip aluminum method in molten AC4C aluminum at 700°C. The result showed that the FeCrAl coating, of which the microstructure was compact, had typical layer structure, and a small amount of oxide films and pores could be found among the lamellar particles. FeCrAl coating mainly contained Fe-Cr solid solution and small amounts of Al2O3. The weight of H13 corrosion was 3 times as much as that of FeCrAl coating corrosion after static melting treatment for 1h, and the corrosion rate of H13 steel and FeCrAl coating were both increased as the corrosion time increased from 1h to 3h. It was worthy noted that the weight of H13 corrosion was significantly increased, which was 17 times as much as that of FeCrAl coating corrosion.

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