• Title/Summary/Keyword: high sulfidation

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Corrosion Behaviour of Fe-XAl-0.3Y Alloys at High Temperature Sulfidation Environment(Ps2=10-3Pa) (Fe-XAl-0.3Y 합금의 고온 황화환경(Ps2=10-3Pa)에서의 부식거동)

  • Lee Byung Woo;Park Hwa Soon
    • Korean Journal of Materials Research
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    • v.14 no.8
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    • pp.547-551
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    • 2004

  • The sulfidation behaviour of Fe-XAl-0.3Y(X=5, 10, 14, 25 $wt.\%$) alloys was investigated at 1123 K in $H_2/H_{2}S$ gas atmosphere for $1\sim24$ hrs using SEM/EDX, XRD and EPMA. The weight changes of Fe-XAl-0.3Y alloys followed the parabolic rate law, Sulfidation rates of iron aluminide alloys with high Al content were one-twentieth lower than that of 5Al alloys. This is due to the formation of protective $Al_{2}O_3$ oxides on the surface of 10Al, 14Al and 25Al alloys. By calculating partial pressure of impurity oxygen contained $H_2/H_{2}S$ gas, the $Al_{2}O_3$ oxides formation could be explained using Fe-Al-S-O thermodynamic stability diagram. The sulfidation product scales of the 5Al alloy showed that thick iron sulfide scale(FeS) containing porosities formed during early stages of sulfidation. With continued sulfidation, aluminum sulfide was formed at the alloy/scale interface.

  • https://doi.org/10.3740/MRSK.2004.14.8.547 인용 PDF KSCI

The Sulfidation and Oxidation Behavior of Sputter-Deposited Nb-Al-Cr Alloys at High Temperatures

  • Habazaki, Hiroki;Yokoyama, Kazuki;Konno, Hidetaka
    • Corrosion Science and Technology
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    • v.2 no.3
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    • pp.141-147
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    • 2003

  • Sputter-deposited Nb-Al-Cr alloys. $3-5{\mu}m$ thick, have been prepared on quartz substrates as oxidation-and sulfidation-resistant materials at high temperatures. The oxidation or the alloys in the $Ar-O_2$ atmosphere of an oxygen partial pressure of 20 kPa follows approximately the parabolic rate law, thus being diffusion controlled. Their oxidation rates are almost the same as or even lower than those ofthc typical chromia-forming alloys. The multi-lavered oxide scales are formed on the ternary alloys. The outermost layer is composed of $Cr_2O_3$, which is"mainly responsible for the high oxidation'resistance of these alloys. In contrast to sputter-deposited Cr-Nb binary alloys reported previously, the inner layer is not porous. TEM observation as well as EDX analysis indicates that the innermost layer is a mixture of $Al_2O_3$ and niobium oxide. The dispersion of $Al_2O_3$ in niobium oxide may be attributable to the prevention of the formation of the porous oxide layer. The sulfidation rates of the present ternary alloys arc higher than those of the sputter-deposited Nb-AI binary alloys, but still several orders of magnitude lower than those of conventional high temperature alloys. Two-layered sulfide scales are formed, consisting of an outer $Al_2S_3$ layer containing chromium and an inner layer composed of $NbS_2$ and a small amount of $Cr_2S_3$. The presence of $Cr_2S_3$ in the inner protective $NbS_2$ layer may be attributed to the increase in the sulfidation rates.

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Late Cenozoic Metallogeny of Southwest Hokkaido, Japan

  • Watanabe, Yasushi
    • Proceedings of the KSEEG Conference
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    • 2003.04a
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    • pp.3-6
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    • 2003

  • Southwest Hokkaido (Sapporo-Iwanai district) in the Northeast Japan arc (Fig. 1) is one of the best places to test the correlation among tectonic regime, stress field, magmatic style and hydrothermal mineralization. This paper reviews the Miocene to Pleistocene tectonic framework, geology, magmatic style and stress field of southwest Hokkaido, and correlates them with different types of deposits (Kuroko, epithermal base-metal and precious-metal). (omitted)

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Geophysical Survey in the Taran Area on the Central Kalimantan, Indonesia (인도네시아 중부 칼리만탄 타란지역에서의 물리탐사)

  • 조진동;김인준;박인화
    • Economic and Environmental Geology
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    • v.35 no.2
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    • pp.155-162
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    • 2002

  • There are many typical epithermal deposits scattering in the Taran of central Kalimantan. Indonesia. To get the shallow geological information, we carried out the geophysical exploration: spontaneous potential survey, in-suite magnetic susceptibility measurement and relistivity survey method in this area for a few weeks from September 30th to October 27th in 1997. SP survey (Fluke 27 multimeter)/magnetic susceptibility (EK -7 meter) measurement was carried out with a 250m$\times$10m lattice net in N45$^{\circ}$W direction. The dipole-dipole array resistivity survey was conducted with an electrode spacing of ${\alpha}$=30 m and electrode separation index n=7 at the line 5. The result shows that was the gold bearing quartz vein area can be divided into two type lone: low sulfidation type and high sulfidation type zone. The low resistivity value in the survey line 5 indicated a fracture Bone associated with the high sulfidation zone.

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