Characterization of the oxides formed at 1000°C on the AISI 304 stainless steel by X-ray diffraction and infrared spectroscopy

2008 ◽  
Vol 254 (8) ◽  
pp. 2292-2299 ◽  
Author(s):  
N. Karimi ◽  
F. Riffard ◽  
F. Rabaste ◽  
S. Perrier ◽  
R. Cueff ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Infrared Spectroscopy ◽  
304 Stainless Steel ◽  
X Ray Diffraction ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
X Ray

Corrosion Behaviour of AISI 304 Stainless Steel with Solar Salt Heat Transfer Fluid

2014 ◽  
Vol 922 ◽  
pp. 13-17 ◽  
Author(s):  
Omar Ahmed ◽  
Le Zhou ◽  
Nahid Mohajeri ◽  
Yong Ho Sohn
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Iron Oxide ◽  
Corrosion Behavior ◽  
304 Stainless Steel ◽  
Salt Mixture ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Solar Salt ◽  
X Ray

In an effort to understand the compatibility between the heat transfer medium and the structural materials used in concentrated solar power plants, the corrosion behavior of AISI 304 stainless steel (18 wt.% Cr, 8 wt.% Ni) in a molten solar salt mixture (53 wt. % KNO3, 40 wt. % NaNO2,7 wt. % NaNO3) has been investigated. The 304 stainless steel coupon samples were fully immersed and isothermally exposed to solar salt at 530°C for 250, 500, and 750 hours in air. X-ray diffraction and scanning electron microscopy with X-ray energy-dispersive spectroscopy were employed to examine the extent of corrosion and identify the corrosion products. Oxides of iron were found to be the primary corrosion products in the presence of the molten alkali nitrates-nitrite salt mixture because of the dissolution of the protective chromium oxide (Cr2O3) scale formed on 304 stainless steel coupons. The corrosion scale was uniform in thickness and chromium-iron oxide was found near the AISI 304. This indicates that the scale formed, particularly on the upper layer with presence of sodium-iron-oxide is protective, and forms an effective barrier against penetration of fused solar salt. By extrapolation, annual corrosion rate is estimated to reach 0.784 mils per year. Corrosion behavior of AISI 304 stainless steel is discussed in terms of thermodynamics and reaction paths.

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