X-RAY STUDY ON SOLID SOLUTIONS OF OXYGEN IN HAFNIUM

The solubility of oxygen in the hexagonal close-packed modification of hafnium is investigated. The introduction of oxygen in solid solution increases the hafnium lattice parameters a and c over the entire range of solubility. The axial ratio c/a, however, is practically constant after a slight rise at low oxygen contents. The limit of solubility was found to be 20.6 at.% (HfO/sub 0// sub .//sub 2//sub 6/). Samples with higher oxygen contents contain dioxide as an additional phase. (N.W.R.)