ISSN:
1573-4889
Schlagwort(e):
sulfidation
;
Ni-Mo-Al alloys
;
Ni-Al alloys
;
Al0.55Mo2S4
;
Al2S3
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Maschinenbau
Notizen:
Abstract The sulfidation behavior of five Ni-Mo-Al ternary alloys and two Ni-Al binary alloys was studied over the temperature range 600–800°C in sulfur vapor of 10−2 atm. The effect of sulfur pressure was also investigated at $$P_{S_2 } = 10^{ - 2} $$ and10−4 atm. using two Ni-Mo-Al alloys. The sulfidation of all Ni-Mo-Al andNi-Al alloys followed the parabolic rate law. The sulfidation rate decreasedwith increasing Al content for a given Mo content for Ni-Mo-Al alloys. Twobinary alloys, Ni-13.5Al and Ni-31Al, sulfidized at comparable rates toNi-30Mo-7.5Al, which has excellent sulfidation resistance. The activationenergies for ternary alloys range from 44.8–50.8 kcal/mol, whereas those forNi-13.5Al and Ni-31Al are 41.5 and 39.1 kcal/mol, respectively. Complexscales formed on all Ni-Mo-Al alloys, consisting of an outer layer of nickelsulfide and an inner layer of MoS2, A12S3, and Al0.55Mo2S4. Sulfide scalesformed on Ni-Al alloys were bilayered, consisting of an outer layer of nickelsulfide and an inner layer of A12S3. The low sulfidation rate of the ternaryalloys was attributed to the combined presence of both A12S3 and Al0.55Mo2S4.The sulfidation kinetics of two Ni-Mo-Al alloys are independent of sulfurpressure, suggesting that the growth of the inner layer was the dominant process.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00666807
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