2002 Fiscal Year Final Research Report Summary
MECHANISM OF SIEAM OXIDATION OF IRON-CHROM ALLLYS FOR POWER TENERATION ULTRA-SUPERCRITICAL CONDITION AND SUPPERESION OF
| Project/Area Number |
12450291
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
MURAYAMA Toshio TOKYO INSTITUTE OF TCHNOLOGY, GRADUATE SCHOOL OF SIENCE AND ENGINEERING, PROFESSOR, 大学院・理工学研究科, 教授 (20114895)
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| Co-Investigator(Kenkyū-buntansha) |
OYAMA Yukiko TOKYO INSUTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF SIENCE AND ENGINEERING, RESAERCH ASSOCIATE, 大学院・理工学研究科, 助手 (00345373)
NANKO Makoto TOKYO INSTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF SIENCE AND ENGINEERING, RESAERCH ASSOCIATE, 大学院・理工学研究科, 助手 (90272666)
KAWAMURA Kenichi TOKYO INSTITUTE OF TECHNOLOGY, GRADUATE SCHOOL OF SIENCE AND ENGINEERING, ASSOCIATE PROFESSOR, 大学院・理工学研究科, 助教授 (50270830)
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| Project Period (FY) |
2000 – 2002
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| Keywords | STEAM OXIDATION / IRON-CHROMIUM ALLOYS / SUPERHEATER / PROTECTIVE OXIDE SCALE / INTERNAL OXIDATION ZONE / VOID FORMATION / CHEMICAL POTENTIAL DISTRIBUTION / EXFOLIATION |
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| Research Abstract |
Iron-chromium alloys have been used as materials for boiler tubes in power generation and many data were corrected in service conditions. However, the mechanism of steam oxidation has not been clarified yet and the suppression of exfoliation of protective oxide scales is required. The operation with ultra-supercritical water is a key issue to improve energy efficiency and the objects of this project area clarification of the steam oxidation mechanism and suppression of the exfoliation.
The development of the oxide scale at the early stage was observed by transmission electron microscopy. The internal oxidation zone (IOZ) was strongly affected by small amount of added silicon. The growth and disappearance of IOZ contributed to the protectiveness of oxide scales. Many voids, which may govern the exfoliation, existed in the oxide scales. It was revealed that the formation of voids was quantitatively explained by calculation of chemical potential distribution in the scale and of mass conservation. It was suggested that the proton dissolved in the oxide scale might affect the void formation. The study on the permeation of proton through the scale is still in progress.
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