148 Prakt. Met. Sonderband 38 (2006) 
The ODS steel PM2000 shows excellent corrosion protection in this environment. It is clear R 
that the high Al content has a large influence on improving the corrosion resistance of this 
material [9]. In figure 6 the measured amount of oxygen in the SDP is compared with the |} 
calculated amount of oxygen if the elements are oxidized as Fe304, Cro03, Y203 and Al,O3 & 
like the binding energy analysis tells. It can be seen that the oxide is always a mixture of k 
many different oxides. It shows that aluminum and yttrium are completely oxidized through a 
depth of 80nm. Deeper in the surface it is a mixture of metal and oxide until a depth of 180 - 
200nm where the oxygen content is very low. 
Oxygen content [counts] 
1800 
4600 ) + Measured ; 
1400 > Calculated ¢ 
1200 
1000 4 
800 | Y,03+ [8 
600 + AloO3+ ¥ T+ J ow nc 
100 CRQ» pO Ss © 
200 | Fe304 Sa ALO; To Depth z 
nat, Fe Eel, FE [nm] 
0 50 100 150 ZU 
Figure 6. Comparison between the measured amount of O in the oxide layer and the 
calculation based on the stoichiometric amount of O in Cr,03, Fe304, Al,O3 and Y,0s. 
Summary 
» EP823 shows a homogeneous outer oxide layer and an inhomogeneous inner layer 
while strong silicon enrichment is found throughout both layers. 
HT-9 shows lower silicon enrichment in the oxide layer than T91 and a slightly thicker 
oxide layer. This might be based on the higher C content in the HT-9 that uses up 
more silicon to form silicon carbides. 
The nano indentation results show that the oxide layers contain a large amount of 
pores, resulting in lowered hardness and E-modulus. 
PM2000 shows superb corrosion resistance at all test conditions 
It is found that PM2000 forms a thin mixed oxide in which the elements with higher 
oxygen affinity are more prevalent further away from the surface 
Acknowledgements 
The authors wish to thank M. Madrid and F. Niu, LANL, for operating the DELTA Loop, A. 
Johnson, H. T. Thau, and J. Welch, UNLV, for assistance in analyses, and G. Swadener. 
LANL. for assistance in nano indentation measurement.