DEOXIDATION OF TANTALUM WITH SOME REACTIVE METALS
Several reactive metal systems were investigated as possible getters for the removal of oxygen from tantalum. Lithium proved to be unacceptable as a deoxidizing agent because of its high vapor pressure and its corrosiveness toward tantalum at temperatures of 800 deg C and higher. Calcium and calcium-magnesium (18 wt.% Mg) were more satisfactory as gettering agents; in 200 hours at 900 deg C they would reduce the oxygen levels in 0.20-in. diameter tantalum samples from several hundred parts per million to about 20 parts per million. However, the high vapor pressures of these metals at 900 deg C complicated their use. Cerium and cerium-cobalt alloy (12 wt.% Co) were also studied as possible gettering agents. The Ce --Co alloy was not satisfactory because of the formation of a layer of Ta/sub 6/Co/sub 7/ on the surface of the tantalum. Cerium proved to be the most satisfactory deoxidizing agent; at 900 deg C it has a very low vapor pressure, and it can also reduce the oxygen level in tantalum to about 20 ppm at this temperature in 200 hours exposure time. None of the getters lowered the oxygen content of tantalum below 15 ppm under the experimental conditions that were studied. (auth)
- Research Organization:
- Los Alamos Scientific Lab., N. Mex.
- DOE Contract Number:
- W-7405-ENG-36
- NSA Number:
- NSA-18-012552
- OSTI ID:
- 4111670
- Report Number(s):
- LAMS-3022
- Country of Publication:
- United States
- Language:
- English
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