Comparison of a Modified Kjeldahl and vacuum Fusion Techniques for Determination of Nitrogen in Tantalum Alloys
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC
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This report compares results obtained for the determination of nitrogen in the tantalum-base alloys T-111 and T-222 by Kjeldahl and vacuum fusion procedures. The Kjeldahl method used consists of a rapid decomposition with HF-H3PO4-K2CrO4 followed by the highly sensitive colorimetry of nitroprusside-catalyzed indophenol. The vacuum fusion procedure described uses a platinum-tin bath, platinum flux technique. In the 5 to 25 ppm range, the relative standard deviation was 3 to 9 percent by the Kjeldahl procedure and 4 to 8 percent by vacuum fusion. The agreement of the nitrogen results by the two techniques is considered satisfactory.
- Inorganic Chemistry
- Physical Chemistry
- Properties of Metals and Alloys