Mass spectrometric investigation of palladium binary alloy phase stabilities /
A twin-chamber Knudsen effusion cell and positioning device
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=743267401&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A twin-chamber Knudsen effusion cell and positioning device for studying alloys at high temperatures were designed for use with a Nuclide model 12-90HT mass spectrometer. Several experiments are described that were used to determine the instrumental performance. The effect of vapor guide tubes used to limit crossinterference of the effusate from the two chambers was measured. These tubes limited the cross- interference of the effusate from the two chambers to one part in three hundred allowing activity measurements as low as 0.02. The instrument was used to determine the activity of palladium in twelve palladium-niobium and ten palladium zirconium samples ranging from 60%Pd to 97%Pd in the temperature range from 1450K to 1800K. Both alloys exhibited strong deviations from ideal solution behavior even in concentrations as high as 95%Pd. The palladium activities in each of the two phase regions of the phase diagrams at 1600K are:[ ] Numbers in parentheses are estimated uncertainties. Literature values for niobium and zirconium studies were used to estimate corresponding niobium and zirconium activities. These were used to calculate molar formation energies at 1600K. Molar Properties of Formation of Pd-Nb Alloys [ ]Molar Properties[ ] Uncertainties are shown in parentheses. The reasons for the seemingly large uncertainties in the palladiumzirconium system are discussed along with the relative merits of this measurement technique. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | x, 259 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |