Diffusion Rates of51Cr,54Mn and 59Fe in MnCr2O4 and FeCr2O4 Spinels |
| Journal |
Advances in Science and Technology (Volume 46) |
| Volume |
Mass and Charge Transport in Inorganic Materials III |
| Edited by |
P. VINCENZINI and V. BUSCAGLIA |
| Pages |
27-31 |
| DOI |
10.4028/www.scientific.net/AST.46.27 |
| Online since |
October, 2006 |
| Authors |
Jolanta Gilewicz-Wolter,
Z. Żurek,
J Dudala,
Jerzy Lis,
Martah Homa,
Marcin Wolter
|
| Keywords |
Calculation of Diffusion Coefficient, Multitracer Method, Oxidation, Reactive Diffusion, Spinel |
| Abstract |
As the result of oxidation of Cr-Mn steels in SO2 the three layer scale is formed. The
intermediate layer of this scale is composed mainly of MnCr2O4 spinel whereas FeCr2O4 spinel is
present in small amount. MnO dominates in the outer layer. The inner, very thin scale layer
contains oxides/sulfides mixture. The aim of this study was to examine self-diffusion processes in
both spinels by multitracer method of diffusion measurements to know which of the transport
processes during oxidation is the smallest one and deciding on the corrosion rate. In diffusion
experiments the radioisotopes 54Mn, 51Cr and 59Fe were used. The serial sectioning method was
applied to simultaneous evaluation of diffusion rates of chromium, manganese and iron in both
spinels at 1073 K and 1173 K under the pressure of 105 Pa in SO2 containing 10 Pa O2. These
spinels were obtained by modified sol-gel method from nitrates. Structures of the spinels were
examined by X-ray spectrometry. It was found, that the diffusion rates of metals are higher in
MnCr2O4 spinel. Moreover the dominant mechanism of manganese transport (the highest one) in
studied samples is the volume diffusion while chromium and iron are transported mainly through
the high diffusivity paths. |
| Full Paper |
Get the full paper by clicking here
|
| Preview |
Free first page example |
