Effect of Heterogeneous Traces of Impurities in the Raw Materials on Sintered Tungsten.

The different impurities in raw materials such as ammonium paratungstate, tungsten trioxide, blue tungsten oxide, and others were analyzed, using several techniques. Their effects were then investigated on intentionally contaminated samples. It was found that in sintered tungsten holes replaced the impurities; somewhat increased concentrations of impurities were often observed in the vicinity of these holes. Calculations indicate that a few thousandths of 1% of impurity may have significant, unfavorable effects on the production of sintered tungsten.