Abstract
We have studied Sb segregation at MnO/Ag(Sb) ceramic/metal heterophase interfaces employing three-dimensional atom-probe (3DAP) microscopy. Specimens are prepared by the internal oxidation of Ag(Mn) alloys, leading to the formation of nanometer-size MnO precipitates within a Ag(Mn) matrix. Sb is introduced into the internally oxidized specimens with a vapor diffusion treatment. Appreciable Sb segregation is observed only after a subsequent segregation anneal is performed, and the measured interfacial excess of Sb at the MnO/Ag(Sb) interfaces, ΓSbMnO/Ag, is determined directly. The temporal evolution of the MnO precipitates is followed for the different processing steps employed. It is shown that the concentration of silver within the MnO precipitates decreases from an initial value of 45–50 at.% Ag to less than 5 at.% Ag with increasing annealing time at the different processing temperatures. Thus the MnO precipitates form under paraequilibrium conditions and the precipitates inherit Ag from the matrix. With increasing aging time orthoequilibrium conditions prevail and the MnO precipitates reject the silver atoms they inherited from the matrix.
| Original language | English |
|---|---|
| Pages (from-to) | 199 - 211 |
| Number of pages | 13 |
| Journal | Ultramicroscopy |
| Volume | 9 |
| Issue number | 3-4 |
| Publication status | Published - 2001 |
| Event | International Conference on Intergranula and Interphase Boundaries (iib2001) - , Israel Duration: 1-Jan-2001 → … |
Keywords
- atom probe
- field-ion microscopy
- ceramics
- metals
- oxides
- interface
- segregation
- 3-DIMENSIONAL ATOM-PROBE
- HETEROPHASE INTERFACES
- INTERGRANULAR SEGREGATION
- SCALE STRUCTURE
- MGO/CU AG
- CHEMISTRY
- ENERGY