DETERMINATION OF FREE TUNGSTEN IN TUNGSTEN SILICIDE (WSI2).
Rept. for Feb-Jun 65,
AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO
Pagination or Media Count:
The primary concern was to determine whether hydrogen peroxide solution 30 could selectively and quantitatively separate free tungsten from WSi2. The recovery experiments proved that quantitative recoveries from spiked samples by the recommended procedure were possible. When hydrogen peroxide was placed in contact with tungsten silicide at 60 - 70C for 1 to 4 hr in order to study its reactance with the silicide, the results indicated that the concentration of tungsten in the extract attained a maximum value within one hour and remained essentially constant thereafter. The silicon content in the hydrogen peroxide fraction was determined experimentally by applying the spectrophotometric silico-molybdate yellow procedure. Since hydrogen peroxide seriously interfered in the method by intensifying the yellow color, a method was devised to eliminate this source of interference. If a material balance could be determined for each sample with sufficient accuracy and precision, important conclusions could be drawn with regard to the homogeneity of the sample as well as lend support to the validity of the method. The material balance study was greatly dependent upon the analysis of the WSi2 residue following the extraction of free tungsten with hydrogen peroxide.
- Inorganic Chemistry