Effect of surface-applied reactive element oxide on the oxidation of binary alloys containing Cr
The influence of surface-applied Ca,Ce, Hf, La, Y, and Zr nitrate-converted oxides on the oxidation behavior of Co-15 weight percent (w/o) Cr, Co-25 w/o Cr, and Ni-25 w/o Cr alloys at 1000/sup 0/ and 1100/sup 0/C in 1 atm O/sub 2/ was studied. The surface oxides were most beneficial on the established Cr/sub 2/O/sub 3/ forming alloy. Surface-applied CeO/sub 2/,Y/sub 2/O/sub 3/, and La/sub 2/O/sub 3/ were effective in reducing the growth rate of the Cr/sub 2/O/sub 3/ scale and improving the scale adhesion. The presence of these surface oxides also prevented base metal oxide formation and changed the growth direction of the scale. All of these observed effects were similar to those found when the reactive element oxides were present within the alloys. However, the presence of surface HfO/sub 2/ made the oxide scales nonadherent causing a breakaway behavior at the early stage of the oxidation process. None of the surface-applied oxides showed any effects on the non-Cr/sub 2/O/sub 3/ forming alloy, and they acted as a semibarrier on the borderline Cr/sub 2/O/sub 3/ former. Unlike the case of dispersoids present in the alloy, these surface-applied as a semibarrier on the borderline Cr/sub 2/O/sub 3/ layer at alloy Cr levels lower than those normally required to form the Cr/sub 2/O/sub 3/ scale.
- Research Organization:
- Lawrence Berkeley Lab. and Dept. of Materials Science and Mineral Engineering, Univ. of California, Berkeley, CA 94720
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5741475
- Journal Information:
- J. Electrochem. Soc.; (United States), Vol. 134:7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMIUM ALLOYS
OXIDATION
SCALING
COBALT ALLOYS
NICKEL ALLOYS
BINARY ALLOY SYSTEMS
CALCIUM OXIDES
CERIUM OXIDES
DEPOSITS
ELECTROCHEMISTRY
HAFNIUM OXIDES
LANTHANUM OXIDES
METALLURGICAL EFFECTS
MOLECULAR WEIGHT
SURFACE TREATMENTS
VERY HIGH TEMPERATURE
YTTRIUM OXIDES
ZIRCONIUM OXIDES
ALKALINE EARTH METAL COMPOUNDS
ALLOY SYSTEMS
ALLOYS
CALCIUM COMPOUNDS
CERIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
HAFNIUM COMPOUNDS
LANTHANUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
360105* - Metals & Alloys- Corrosion & Erosion