Abstract
The depth profile of oxygen [O] and nitrogen [N] in TIG weld metals of Zircaloy-2 tubing were studied by two methods below.
The calculative estimation from chemical analysis of [N] in weld metals before and after etching was applied to determine the [N] content in surface layers of the weld metals.
And, the direct analysis by SIMS (Secondary Ion Mass Spectrometry) was applied also.
Results obtained from the evaluation by two method avobe are summarized as follows.
(1) The [N] content in a weld metal welded in an atmosphere with high level of PN2 is much higher at upper surface of it and decreases exponentially toward deep inside.
(2) The [N] content at upper surface of weld metals decreases as the PN2 in the welding atmosphere reduces, and its depth profile changes until it becomes flat with weld metals welded in an atmosphere with 0.4 Pa of PN2.
(3) The depth profile of oxygen [O] differs significantly from those of [N].
