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Title: | High Temperature Oxidation Kinetics of a Zr-21/2 w/o Nb Alloy |
Authors: | Urbanic, Vincent F. |
Advisor: | Smeltzer, W.W. |
Department: | Metallurgy |
Publication Date: | Apr-1970 |
Abstract: | <p>An investigation is reported on the oxidation kinetics of a Zr-21/2 w/o Nb alloy in the temperature range 650° - 1000°C in pure oxygen atmospheres. Weight gain data is presented for rectangular plate specimens in the range 650° - 991°C. The kinetics were determined continuously using thermogravimetric techniques and may be represented by a parabolic relationship followed by essentially linear kinetics over the range 650° - 885°C, while over the range 937°- 991°C, parabolic kinetics is followed by a breakaway transition to an increasing reaction rate. In the low temperature range the parabolic rate constant has been calculated to be k = 20.8 exp (-38026/RT) and in the high temperature range kp = 0.22 exp (-30054/RT).</p> <p>The latter part of the investigation was focused on the oxidation of Zr-21/2 w/o Nb at 1000°C in pure oxygen for periods extending to 23 hours. The morphological development of the oxide scale and metal substrate during parabolic oxidation was investigated and is supported by kinetic, X-ray, electron micro-probe and metallographic observations. Spherical specimens were used to minimize edge effects and hence extend the period of parabolic behaviour. The observed microstructures are discussed with reference to the Zr-Nb-0 phase diagram.</p> <p>A qualitative discussion pertaining to observations related to the breakaway phenomenon is also presented.</p> |
Description: | Title: High Temperature Oxidation Kinetics of a Zr-21/2 w/o Nb Alloy, Author: Vincent F. Urbanic, Location: Thode |
URI: | http://hdl.handle.net/11375/20370 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Urbanic_Vincent_F_1970_04_master.pdf | Title: High Temperature Oxidation Kinetics of a Zr-21/2 w/o Nb Alloy, Author: Vincent F. Urbanic, Location: Thode | 22.78 MB | Adobe PDF | View/Open |
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