Abstract
dc:description.abstractThis project investigated the reactive formation of hafnium diboride (HfB2) in a variety of metallic environments, including blends with Bi, Cu, Ni, and Sb. HfB2 has garnered interest for a variety of applications due to its hardness, stability at elevated temperatures, as well as electrical and thermal conductivity. Experimental testing included differential scanning calorimetry (DSC) to reveal reaction initiation temperatures and enthalpies of reaction; and optical pyrometry to measure maximum reaction temperatures. Overall, DSC results indicated melting preceded reaction initiation; suggesting that the reaction initiation temperature for a certain blend occurred soon after melt formation, and could be broadly approximated by examination of binary phase diagrams. However, compositions containing bismuth ignited almost 200 ºC above the expected melting temperature. The maximum temperature measurement did not appear to correlate with reaction enthalpies as might be expected. This lack of correlation may be a result of an inability to capture the true maximum temperature due to the measurement frequency of the pyrometer, the disparity of heating rates between the two experimental methods, and/or to the influence of intermediate reactions on the temperature increase.
Degree
thesis:*- Name thesis:degree_name
- Master of Science
- Level thesis:degree_level
- masters
- Discipline thesis:degree_discipline
- Materials Science and Engineering
- Department dc:contributor.department
- Materials Science and Engineering
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2009
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Dykema, Christopher Patrick
- Chair dc:contributor.committeechair
-
- Kampe, Stephen L.
- Committee members dc:contributor.committeemember
-
- Pickrell, Gary R.
- Aning, Alexander O.
Subjects
dc:subject × 2Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- etd-03192012-142230
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/41733