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Improved crystal quality by detached solidification in microgravity (Document No: 20030060509)
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Wang, Yaz-Hen Wang, Jian-Bin Wilcox, William R. Regel, Liya L. |
| Copyright Year | 2003 |
| Description | Many microgravity directional solidification experiments yielded ingots with portions that grew without contacting the ampoule wall, leading to greatly improved crystallographic perfection. Our long term goals have been: (1) To develop a complete understanding of all of the phenomena of detached solidification.; (2) To make it possible to achieve detached solidification reproducibly; (3) To increase crystallographic perfection through detached solidification. We have three major achievements to report here: (1) We obtained a new material balance solution for the Moving Meniscus Model of detached solidification. This solution greatly clarifies the physics as well as the roles of the parameters in the system; (2) We achieved detached solidification of InSb growing on earth in BN-coated ampoules; (3) We performed an extensive series of experiments on freezing water that showed how to form multiple gas bubbles or tubes on the ampoule wall. However, these did not propagate around the wall and lead to fully detached solidification unless the ampoule wall was extremely rough and non-wetted. |
| File Size | 1437550 |
| Page Count | 9 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20030060509 |
| Archival Resource Key | ark:/13960/t6p034d6q |
| Language | English |
| Publisher Date | 2003-02-01 |
| Access Restriction | Open |
| Subject Keyword | Solid-state Physics Crystal Defects Directional Solidification Crystals Phase Transformations Quality Control Mathematical Models Ingots Microgravity Crystallography Drying Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
