Abstract
During vapor-phase deposition at 1273 K (1000 °C), by pack cementation, of Mo onto 127-μm-diameter Ni wires, two phenomena are observed to occur concurrently, leading to strong surface roughening: (i) the inward radial growth of Kirkendall pores below the wire surface and (ii) the outward growth from the wire surface of protuberances with sizes as large as 15 μm. High-aspect-ratio Kirkendall pores as long as 21 μm are created because of imbalanced interdiffusion between Mo and Ni. These pores in turn, by reducing the flow of Mo into the wires, may enhance the outward growth of Mo-rich protuberances, further roughening the wire surface. These protuberances have faceted tips as well as terraces and steps, indicating that their growth is governed by the vapor–solid–solid mechanism.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 6252-6259 |
| Number of pages | 8 |
| Journal | Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science |
| Volume | 45 |
| Issue number | 13 |
| DOIs | |
| State | Published - Oct 24 2014 |
Funding
We acknowledge funding by DARPA under award number W91CRB1010004 with Dr. Judah Goldwasser as grant monitor. We thank Dr. Dinc Erdeniz and Ms. Ashley Paz y Puente (both of Northwestern University) for useful discussions, and Dr. Dinc Erdeniz for metallographic preparation of the as-received wire.
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys