High Temperature Corrosion Resistance of Selected Thermally Sprayed Carbide and Alloy Based Coatings in Aggressive Environment at 690 °C

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47718684%3A_____%2F19%3AN0000010" target="_blank" >RIV/47718684:_____/19:N0000010 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

High Temperature Corrosion Resistance of Selected Thermally Sprayed Carbide and Alloy Based Coatings in Aggressive Environment at 690 °C

Original language description

An effort to increase the efficiency of boilers for solid fuels leads to the increase is their operating temperature. This increase in operating temperatures of boilers is limited by the corrosion resistance of individual components. The high temperature corrosion of superheater and reheater pipes is a serious problem leading to the gradual decrease in the thickness of pipe walls. No alloy is resistant to the high temperature corrosion for an unlimited time period. Even if there are some alloy compositions that have a long initiation period before the corrosion damage occurs; these superalloys designed for the high temperature applications do not provide satisfying thermal stability and resistance to the high temperature corrosion. For this reason, the thermally sprayed coatings are applied on components operating at high temperatures in order to provide the base material with resistance to the high temperature corrosion. This study deals with the evaluation of corrosion resistance by selected carbide and alloy-based coatings applied using HP/HVOF technology on the chromium-molybdenum steel substrate. Specifically, they are Cr3C2-25%NiCr, NiCrMoWFe and Cr3C2-50%NiCrMoNb coatings. The evaluated materials were exposed to the corrosive environment of Na2SO4 and 82% Fe2(SO4)3. This corrosive environment simulates the real conditions in the combustion boilers of thermal power plants. The high temperature corrosion testing was performed under the cyclic conditions at the temperature of 690 °C. The corrosion resistance of all evaluated specimens was evaluated using the thermo-gravimetric method in order to determine the kinetics of corrosion products. After the exposure to the corrosive environment, specimens were further examined using optical microscope OM and scanning electron microscope SEM. In addition, elemental analyses EDS and XRD X-ray diffraction analysis were conducted. All specimens were further evaluated in terms of micro-hardness HV0.3 in as-sprayed state and after the high temperature corrosion testing. NiCrMoWFe coating showed the best corrosion resistance in comparison with other evaluated specimens.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20506 - Coating and films

Project

<a href="/en/project/TE01020068" target="_blank" >TE01020068: Centre of research and experimental development of reliable energy production</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů