Research on a Surface Shot Peeling Process for Increasing the Anti-Oxidation Property of Super304H Steel in High-Temperature Steam

2014 ◽  
Vol 908 ◽  
pp. 77-80 ◽  
Author(s):  
Yan Hui Li ◽  
Shu Zhong Wang ◽  
Pan Pan Sun ◽  
Xue Dong Li
Keyword(s):  
High Temperature ◽  
Shot Peening ◽  
Austenitic Steels ◽  
Detailed Surface ◽  
Before And After ◽  
Main Chemical Composition ◽  
Oxidation Properties ◽  
High Temperature Steam ◽  
Super304h Steel ◽  
Generation Unit

At present, the superheater and reheater pipes in supercritical and ultra-supercritical boilers have encountered with widespread problems of high temperature steam oxidation, seriously affecting the operation safety and economy of the power generation unit. After several tests and contrastive analysis on the main chemical composition and microstructure of specimens before and after shot peening treatment, this paper developed a set of detailed surface shot peening process with specific process parameters, and finds that for the Super304H oxide film, the relative content of Cr element increases by shot peening treatment, with the relative Cr content of the treated specimen being 2.65% higher than that of the untreated, displaying that the anti-oxidation properties of high chromium austenitic steels in high temperature steam is effectively increased.

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.

Interdiffusion and Reaction of Pd on Atomically Stepped 6H-SiC Surfaces: Progress Toward Thermally Stable High Temperature Gas Sensors

2004 ◽  
Vol 828 ◽  
Author(s):  
C. D. Stinespring ◽  
C. Y. Peng ◽  
A. A. Woodworth ◽  
K. Meehan ◽  
M. J. Murdoch-Kitt ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Sensors ◽  
Quantitative Information ◽  
Device Fabrication ◽  
Ex Situ ◽  
Reaction Products ◽  
Semiconductor Interface ◽  
Thermally Induced ◽  
Detailed Surface ◽  
Before And After

ABSTRACTHigh temperature Pd-SiC Schottky diode gas sensors are known to thermally degrade due to interdiffusion and reaction at the metal-semiconductor interface. To understand and possibly eliminate this problem, detailed surface studies of thermally induced Pd-SiC surface interactions have been performed. These experiments compare standard 6H-SiC (0001) surfaces typical of those used in device fabrication with periodically stepped surfaces prepared by high temperature hydrogen etching. The Pd films range in thickness from the monolayer level (∼0.4 nm) to actual device dimensions (∼46.5 nm) and are deposited under ultrahigh vacuum conditions at ∼50 °C. These films are characterized in-situ using Auger electron spectroscopy both before and after annealing at 670 °C. The Auger lineshapes provide quantitative information on the chemistry of the reaction products. Ex-situ atomic force microscopy is used to characterize changes in surface morphology.

Simulation of high-temperature steam-only gasification of woody biomass with dry-sorption CO2capture

2016 ◽  
Vol 94 (9) ◽  
pp. 1648-1656 ◽  
Author(s):  
Ehsan Mostafavi ◽  
Jennifer H. Pauls ◽  
C. Jim Lim ◽  
Nader Mahinpey
Keyword(s):  
High Temperature ◽  
Woody Biomass ◽  
High Temperature Steam

High activity oxide Pr0.3Sr0.7Ti0.3Fe0.7O3−δ as cathode of SOEC for direct high-temperature steam electrolysis

2017 ◽  
Vol 42 (17) ◽  
pp. 12104-12110 ◽  
Author(s):  
Lijuan Zhang ◽  
Zhihong Wang ◽  
Zhiqun Cao ◽  
Lin Zhu ◽  
Pengzhang Li ◽  
...  
Keyword(s):  
High Temperature ◽  
High Activity ◽  
High Temperature Steam

scholarly journals Novel Multilayer SAW Temperature Sensor for Ultra-High Temperature Environments

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 643
Author(s):  
Xuhang Zhou ◽  
Qiulin Tan ◽  
Xiaorui Liang ◽  
Baimao Lin ◽  
Tao Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Sensor ◽  
X Ray Diffraction ◽  
Aero Engine ◽  
Before And After ◽  
Application Potential ◽  
Passive Sensors ◽  
Temperature Exposure ◽  
Engine Systems

Performing high-temperature measurements on the rotating parts of aero-engine systems requires wireless passive sensors. Surface acoustic wave (SAW) sensors can measure high temperatures wirelessly, making them ideal for extreme situations where wired sensors are not applicable. This study reports a new SAW temperature sensor based on a langasite (LGS) substrate that can perform measurements in environments with temperatures as high as 1300 °C. The Pt electrode and LGS substrate were protected by an AlN passivation layer deposited via a pulsed laser, thereby improving the crystallization quality of the Pt film, with the function and stability of the SAW device guaranteed at 1100 °C. The linear relationship between the resonant frequency and temperature is verified by various high-temperature radio-frequency (RF) tests. Changes in sample microstructure before and after high-temperature exposure are analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The analysis confirms that the proposed AlN/Pt/Cr thin-film electrode has great application potential in high-temperature SAW sensors.

Characteristics of Phenomena in Powders Type RE2Zr2O7-Al2O3 in High Temperature Annealing Conditions

2011 ◽  
Vol 312-315 ◽  
pp. 583-588 ◽  
Author(s):  
Grzegorz Moskal ◽  
Lucjan Swadźba ◽  
Marek Hetmańczyk ◽  
Bartosz Witala
Keyword(s):  
High Temperature ◽  
Perovskite Oxide ◽  
Differential Scanning Calorimetric ◽  
Test Results ◽  
Dsc Analysis ◽  
Annealing Conditions ◽  
Before And After ◽  
Influence Of Temperature On ◽  
Dta Analysis ◽  
Type Bond

The paper presents test results and characterizes the structural stability of powders, which form a mixture of aluminium oxide (Al2O3) and gadolinium, based on rare earth zirconates. This mixture is provided to create thermal barrier coatings (TBCs) by spraying. The purpose of the tests was to determine the influence of temperature on reactions, occurring between those powders within a temperature range from 25°C to 1500°C, while such conditions were to simulate the conditions, which occur during creation of TBCs and they give an answer to the question concerning mutual reactivity of the powders. The requirements for new materials, provided to spray the TBCs, indicate the necessity to prepare the materials, which do not show tendency towards reactions with the Al2O3, formed during oxidation of Ni (Co) CrAlY, while this reaction is of type bond coat. The tests included differential scanning calorimetric (DSC) analysis and differential thermal analysis (DTA) of powder mixtures. Diffraction analysis was also performed before and after the tests have been finished. The DSC analysis results, obtained at a range of high temperature, did not show any thermal effects, which indicate a low level of mutual reactivity of the powders. However, the DTA analysis suggests presence of such effects at temperature close to 1300°C, and it indicates the necessity to verify exactly the obtained results. Results of the XRD measurement showed that after annealing process already at 1100°C the perovskite oxide of GdAlO3 was present.

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