1992 Fiscal Year Final Research Report Summary
In-situ Observation of Initial Reaction Stages of Hot-Corrosion
| Project/Area Number |
03452252
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
NARITA Toshio HOKKAIDO UNIVERSITY, DEPARTMENT OF METALLURGICAL ENGINEERING PROFESSOR, 工学部, 教授 (60001252)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Hot corrosion / In-situ observation / Sulfidation / Hot stage / Fused salt / Melting phenomena / boundary corrosion / boiler-turbine |
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| Research Abstract |
In oil fired boiler and gas turbine systems high-temperature hot corrosion is increasing concerns, because of its aggressiveness. Mechanisms of the hot corrosion have been studied by using electrochemistry and fused salt chemistry, whereas there is little information on the initial stage of the hot corrosion.
In this research project the scanning electron microscope was developed to observe the melting process in various corrosion environments.
The results obtained are summarized as follows.
(1) Differential evacuation system was installed to SEM in order to keep sample chamber in various corrosion environments. (2) Hot stage was installed, heating up to 500ﾟC. (3) Several samples, alloy with low melting temperature of 90ﾟC, mixed salt of ZnCl_2-KCl with 200ﾟC m.p., and pure tin metal with 231ﾟC m.p., were observed in the low air pressure and the melting and solidifing processes were observed clearly. However, details of the melting process was not observed because of rapid change in states. In order to overcome this difficulty. the video-monitoring system should be needed. (4) Sulfidation process of Fe-Cr alloys was investigated in low sulfur pressures in order to elucidate the mechanism of grain boundary attack. (5) Gaseous corrosion associated with sulfidation was summarized and critically reviewed.
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