Effect of rare earth oxide additions on oxidation behavior of AISI 304L stainless steel

Abstract

AISI 304L stainless steel powder compacts containing 2 vol% high purity rare earth oxides were prepared by mixing the different powders in a vibratory mill followed by pressing. The compacts thus obtained were sintered in a vacuum furnace and isothermal oxidation measurements were carried out in a muffle furnace, in air, up to 200 hours at 900 °C. The oxidized surfaces were examined in a scanning electron microscope and micro regions of the reaction products were studied using energy dispersive analysis. The addition of rare earth oxides decreased the oxidation rate of the stainless steel. Further evidence of predominant oxygen ion diffusion controlling the overall oxidation process in rare earth containing chromium oxide forming alloys has been observed.

Kinetics Oxidation and Characterization of Cyclically Oxidized Layers at High Temperatures for FeMnSiCrNiCe and FeSiCrNi Alloys

“…Li et al 17 , studying high temperature oxidation of a 17Cr ferritic stainless steel (low Mn-content) observed increase of chromium and decrease of manganese content in oxide layer in cerium-bearing steels. The use of different rare earth oxides in a AISI 304L austenitic stainless steel sintered also improved the oxidation resistance 18 . Therefore, the objective of the present research was to study oxidation resistance at high temperatures of FeSiCrNi and FeMnSiCrNiCe low-cost alloys (low Cr and Ni content), comparing them with conventional austenitic stainless steels and to evaluate mass variation through cyclic oxidation tests.…”

“…However, one of the reasons to avoid the high use of silicon in iron based alloys is related to the embrittlement generated 13,14 . Rare earths, like cerium and yttrium, are also used to improve oxidation resistance in Fe-based alloys [15][16][17][18] . Rhys-Jones and Grabke 16 studied the oxidation of Fe-Cr alloys using either 0.0001 to 1% of Ce or CeO 2 and 10 to 20% of Cr.…”

High Temperature Oxidation Behavior of Yttrium Dioxide Coated Fe-20Cr Alloy

“…In Y containing or Y 2 O 3 coated alloys, the Y ion in the oxide scale segregates to the grain boundaries and its radius (1.02 Å) being larger than the Cr and Fe ions (0.615 Å and 0.78 Å respectively) blocks the path of the diffusing alloy cations, decreasing thereby the oxidation rate of the alloy. 6,36 Hence, the influence of the Y 2 O 3 coating in reducing the oxidation rate of chromia forming alloys is twofold. It increases oxygen ion vacancies and thereby oxygen ion diffusion in the YCrO 3 compound.…”

“…The use of reactive elements, especially rare earths (RE) to improve high temperature oxidation resistance of chromium dioxide and alumina forming alloys is quite well documented. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] The improvements are in the form of reduced oxidation rates and increased scale adhesion. The RE can be added to the alloy in elemental form or as oxide dispersions.…”

“…It can also be applied as an oxide coating to the alloy surface. [3][4][5][6][7]15 Various mechanisms have been proposed to explain the effect of reactive elements in improving oxidation resistance and the most widely accepted mechanism attributes it to segregation of the reactive elements to the interface or to the oxide scale grain boundaries and blocking of Cr ion diffusion though the oxide scale [8][9][10][11] Studies carried out by Seo et al, about the effect of addition of Ce, La and Y to a Fe-22Cr-0.5Mn alloy on the oxidation behavior of the alloy at 800 °C, indicated that Y was the most effective element to reduce the growth rate of the oxide scale. 12 In recent years a number of studies have been carried out to exploit the benefits of rare earth additions on oxidation behavior of chromium dioxide and alumina forming alloys.…”