High Temperature Sulfidation Resistance of DO3 - Ordered FeAl Tested in H2S-rich Gases

2006 ◽  
Vol 980 ◽  
Author(s):  
Pierre-Yvan Thery ◽  
Anna Fraczkiewicz ◽  
Cecile Genevois ◽  
Xavier Longaygue ◽  
Francois Ropital
Keyword(s):  
Stainless Steel ◽  
Corrosion Test ◽  
Nucleation And Growth ◽  
Iron Aluminides ◽  
Gas Mixture ◽  
Iron Sulfides ◽  
Alumina Layer ◽  
Oxidation Treatment ◽  
Ordered Alloys ◽  
Severe Deterioration

AbstractThe sulfidation behaviour at 973 K in a 30 vol.% H2S-H2-H2O-N2 gas mixture of Fe-25 % at. Al, DO3-ordered alloys, binary or alloyed with niobium, was investigated. Binary alloys presented a quite good sulfidation resistance in comparison with 321 stainless steel, even if a large amount of iron sulfides FeS grew over the alumina layer on corroded samples. The sulfidation resistance of DO3 alloys could be significantly improved by an oxidation treatment prior to corrosion test. The Nb in iron aluminides was supposed to preferably react with S and therefore, to enhance sulfidation resistance through preventing the nucleation and growth of harmful FeS. Unfortunately, the scales of Nb-allloyed FeAl contained only a small amount of Nb3S4 which did not prevent efficiently the formation of iron aluminides FeS. Adding Nb to Fe-25Al even resulted in a severe deterioration of the microstructure during sulfidation due to intense diffusion of S inward the sample.

Effect of Sensitization Time on Intergranular Corrosion of 347H Stainless Steel

2021 ◽  
Vol 904 ◽  
pp. 506-511
Author(s):  
Liang Chang ◽  
Xue Tao Zhang ◽  
Zhi Juan Zhao ◽  
Yun Yan Peng ◽  
Jing Miao Li ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Intergranular Corrosion ◽  
Corrosion Test ◽  
Double Loop ◽  
Maximum Value ◽  
Microscopic Morphology ◽  
Epr Test ◽  
Sensitization Time

In this paper, 347H stainless steel of three situation of solution, primary and secondary stabilizing with 0, 12, 24, 48 and 72 h accelerated sensitization heat treatment. The change of sensitization degree with time was studied by metallographic test, double-loop electrochemical potentiodynamic reactivation (DL-EPR) test, intergranular corrosion test and microscopic morphology observation. The result shows that the sensitization degree of the solution material increases rapidly and reaches the maximum value after 12h sensitization heat treatment. After that, it still belonged to severe sensitization situation, but the index gradually decreased. After stabilizing heat treatment, the sensitization degree of the material is lower than the situation of solution. After heat treatment for 48h, the material located on “possible sensitization” range, and the sensitization degree of the secondary stabilized material was always lower than is of the primary. It indicates that the sensitization of materials can not be completely inhibited by stabilizing heat treatment, and other anti-corrosion measures should be considered.

Corrosion Behaviour of Steel Nitrided and Nitrocarburized in Gas, Respectively

2015 ◽  
Vol 365 ◽  
pp. 278-284
Author(s):  
Hisao Fujikawa ◽  
H. Iwamura ◽  
M. Uramoto
Keyword(s):  
Corrosion Test ◽  
Corrosion Behaviour ◽  
Plasma Nitriding ◽  
Salt Spray ◽  
Salt Bath ◽  
Carbon Steels ◽  
Test Method ◽  
Oxidation Treatment ◽  
Gas Nitriding ◽  
Nitride Layers

Nitriding treatment is well known as one of the corrosion protection methods for steels as well as a way to prevent wear and fatigue. Initially, salt bath nitrocarburizing was popular, but recently, gas nitriding, gas nitrocarburizing, plasma nitriding and so on have come to be used more often because of their superior nitriding ability. In the case of nitriding, only nitrogen (N) diffuses into the steel, but in the case of nitrocarburizing, both nitrogen and carbon (C) diffuse into the steel. General speaking, nitriding includes all the treatments mentioned above. The corrosion behavior of nitride carbon steels has been understood mainly by salt bath or gas nitrocarburizing treatments1)-4).However, recently, nitriding is mainly applied to parts for things such as automobiles which need protection from wear and fatigue, and is seldom used for parts which need corrosion resistance. The present paper is to remind researchers again that nitrided steels show good corrosion resistance.Therefore, the comparison of various thicknesses of nitride layers as well as the comparison between nitride layers on steel has been carried out in this examination, using the salt spray corrosion test method. The effect of oxidation treatment after nitriding was also investigated.

INFLUENCE OF SUBSTRATE TOPOGRAPHY ON THE NUCLEATION AND GROWTH OF 321 STAINLESS STEEL THIN FILMS PRODUCED BY MAGNETRON SPUTTERING

2008 ◽  
Vol 15 (04) ◽  
pp. 411-418 ◽  
Author(s):  
YONGZHONG JIN ◽  
DONGLIANG LIU ◽  
WEI WU ◽  
YALI SUN ◽  
ZUXIAO YU ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Magnetron Sputtering ◽  
Active Sites ◽  
Nucleation And Growth ◽  
Textured Surfaces ◽  
Force Microscopy ◽  
Substrate Topography ◽  
Atomic Force ◽  
Nucleation Sites ◽  
Influence Of Substrate

We have investigated the effects of substrate topography on the nucleation and growth behavior of 321 stainless steel (ss) films, introducing textured surfaces into mica substrates by the abrasion treatment. In this study, two groups of samples were prepared at three different sputtering time within 12 s using radio frequency (r.f.) magnetron sputtering and characterized by atomic force microscopy. Good nucleation uniformity has been obtained on the unabraded mica substrates due to the statistical distribution of nucleation sites. Especially, we have already observed an interesting unusual nucleation phenomenon, the island–rim structure on the abraded mica substrates after 4 s, where the island is fractal-like and the rim around the island was only occupied by few grains for nucleation. These ramified islands were located at the wide grooves introduced as predominate nucleation sites. The island–rim structure formed in initial nucleation process is closely associated with x, y velocity components of surface atoms and the distribution of active sites (related intimately to the surface free energy σ and strain energy ε) for nucleation. With the increasing of the sputtering time, voids and overlarge grains have been observed in the island–rim region after the sputtering time of 8 s and 12 s, respectively.

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