On the kinetics of oxidation of austenitic stainless steels AISI 304 and incoloy 800H

Abstract

The interaction of oxygen with clean surfaces of stainless steels has been studied by spectroscopic ellipsometry and AES. The reaction involves chemisorption and dissolution of oxygen into the surface of the metal via a place-exchange mechanism.Oxide thickening occurs via cation and anion migration under the influence of an electric field. The activation energy increases with increasing oxide thickness and the final activation energy equals the energy needed to break the bonds between oxygen and metal ions in the oxide, suggesting diffusion via lattice sites.

On the oxide formation on stainless steels AISI 304 and incoloy 800H investigated with XPS

“…Previous studies [l-4] show a small influence of cold work on the oxidation behaviour of AISI 304 and Incoloy 800H under atmospheric [1,2] as well as under UHV [3,4] conditions. Cold work, however, does not seem to alter the mechanism of the oxidation but only to affect the diffusion rates in the oxide as well as in the metal and in this way influences the oxidation rate.…”

Rare earths oxide film effect on different metal and alloys at high temperature in oxidizing conditions

“…The rate constants kp measured from the linear plots Am/S=f(Vt) were respectively 1,8.10" 12 and kp=5,1.10' 12 g 2 cm"V 1 at 950 and 1000 C C. Under thermal cycling conditions (Fig 4) scale spallation appeared after 5 or 7 cycles. Protective oxide scale growth was by cation diffusion (12,14,18,19). The corrosion rate is monitored by a diffusion process in the chromia subscale .…”

Effects of Heat Input on the Mechanical and Metallurgical Characteristics of Tig Welded Incoloy 800Ht Joints

“…Precipitation of γ' contributes to high temperature strength and creep resistance of the material, with the strength increasing as γ' volume fraction increases. The volume fraction of γ' in iron-nickel-base alloys is usually less than 25% [2,3]. The higher carbon content and coarser grain size provide 800H with greater high-temperature strength [4].…”