Effect of Phosphoric Acid Treatment on Isothermal High Temperature Oxidation Behaviour of AISI 304 Stainless Steel at 800°C

2012 ◽  
Vol 323-325 ◽  
pp. 359-364
Author(s):  
F. Riffard ◽  
Henri Buscail ◽  
F. Rabaste ◽  
Christophe Issartel ◽  
Sébastien Perrier
Keyword(s):  
High Temperature ◽  
Phosphoric Acid ◽  
Acid Treatment ◽  
High Temperature Oxidation ◽  
304 Stainless Steel ◽  
Protective Oxide ◽  
Temperature Oxidation ◽  
Aisi 304 ◽  
Oxidation Test ◽  
Aisi 304 Steel

Phosphoric acid treatment is used as a way to improve the high temperature oxidation resistance of a chromia-forming AISI 304 steel. Chromia-forming steels are excellent candidates to resist to high temperature oxidizing atmospheres because of the formation of protective oxide scales. The oxide scale growth mechanisms are studied by exposing phosphoric acid-treated and untreated 304 steel samples to high temperature conditions in air. The analyses were carried out by means of thermogravimetry, andin situX-ray diffraction (XRD). The experimental results show that the phosphoric acid treatment does not have a beneficial effect on cyclic high temperature oxidation (up to 70h of the oxidation test) of AISI 304 steel because of growth of a layer mainly formed by external cation diffusion which grows very quickly. The isothermal high temperature oxidation of this steel at 800°C in air shows a very fast initial iron oxidation towards the external interface, allowing to chromium element to be more available to the internal interface to form a continuous chromia layer, thus causing the establishment of a parabolic oxidation regime and leading to a beneficial reduction of the oxidation rate (after 70h of the oxidation test).

Manganese Effect on Isothermal High Temperature Oxidation Behaviour of AISI 304 Stainless Steel

2008 ◽  
Vol 595-598 ◽  
pp. 1127-1134 ◽  
Author(s):  
Frédéric Riffard ◽  
Henri Buscail ◽  
F. Rabaste ◽  
Eric Caudron ◽  
Régis Cueff ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Oxide Scale ◽  
304 Stainless Steel ◽  
Initial Growth ◽  
Aisi 304 Stainless Steel ◽  
Protective Oxide ◽  
Temperature Oxidation ◽  
Aisi 304

Chromia-forming steels are excellent candidates to resist to high temperature oxidizing atmospheres because they form protective oxide scales. The oxide scale growth mechanisms are studied by exposing AISI 304 stainless steel to high temperature conditions in air, and the analyses were carried out by means of thermogravimetry and in situ X-rays diffraction. The in situ XRD analyses carried out during high temperature AISI 304 steel oxidation in air reveals the accelerated growth of iron-containing oxides such as hematite Fe2O3 and iron-chromite FeCr2O4, when the initial germination of the oxide layer contains the presence of a manganese-containing spinel compound (1000°C). When the initial growth shows the only chromia formation (800°C), hematite formation appears differed in time. Protection against corrosion is thus increased when the initial germination of manganese-containing spinel oxide is inhibited in the oxide scale.

scholarly journals Effect of Mullite Film Layers on the High-Temperature Oxidation Resistance of AISI 304 Stainless Steel

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 880
Author(s):  
Jing Ma ◽  
Ning Wen ◽  
Ruiyang Wang ◽  
Jiangang Wang ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Cyclic Oxidation ◽  
304 Stainless Steel ◽  
Sintering Process ◽  
Aisi 304 Stainless Steel ◽  
Temperature Oxidation ◽  
Aisi 304

Protective coating is an effective way to extend materials’ high-temperature service life. In order to improve the high-temperature oxidation resistance of AISI 304 stainless steel, mullite films with different layers were successfully prepared by the sol-gel method and the sintering process on the surface of stainless steel. The effect of the film layers on the high-temperature oxidation resistance of stainless steel at 900 °C for 100 h was studied. The analysis results of oxidation kinetics, X-rays diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis (EDS) show that Al1.4Si0.3O2.7 mullite film effectively improved the high-temperature oxidation resistance of stainless steel. The sample with three-layer mullite film has the best high-temperature oxidation resistance. The mass gain and oxidation spalling mass are only 4.6% and 34.5% of those of the uncoated sample after 100 h cyclic oxidation at 900 °C. A chromium oxide layer was formed at the interface of mullite film and the substrate during the sintering process. The generation of selective Cr2O3 scale was promoted at the cyclic oxidation stage so that the sample with three-layers has excellent high-temperature oxidation resistance.

The Nitridation, a Way to Improve High Temperature Oxidation Behaviour of AISI 304

2008 ◽  
Vol 595-598 ◽  
pp. 987-994 ◽  
Author(s):  
Christophe Issartel ◽  
Henri Buscail ◽  
Eric Caudron ◽  
Régis Cueff ◽  
Frédéric Riffard ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
X Ray Diffraction ◽  
Protective Oxide ◽  
Temperature Oxidation ◽  
Aisi 304 ◽  
Solid Solution Formation ◽  
X Ray ◽  
Solution Formation

The present study focuses on the high temperature oxidation of a AISI 304 chromiaforming nitrided alloy. Isothermal oxidations were performed in air, at 800°C. The effect of nitridation on the steel surface depends on the temperature of the treatment. It leads whether to a γN solid solution formation or to CrN formation. In situ X-ray diffraction has been used to follow the oxides formation. Results show the concomitant growth of CrN and Fe2O3 at the beginning of the test. Then, Cr2O3 quickly appears which leads to the formation of a protective oxide scale (a parabolic rate law is observed). Our conclusions suggest that nitridation increases the high temperature oxidation resistance of 304 steels at 800°C.

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