Characterization of Oxygen-Enriched Layers of TA6V, Titanium, and Zirconium by Scanning Microwave Microscopy

A technique based on scanning microwave microscopy (SMM) has recently been developed to analyze solid solutions of light elements. This technique consists in local measurements of effects produced by electrical conductivity variations produced by light elements solutions in metals. The penetration of the microwaves into the metals depends on their frequency and the material parameters. Information regarding the local conductivity of the material at different depths can be recorded using various frequencies. In this paper, SMM measurements of the oxygen-enriched zone are presented for several materials: TA6V, pure Ti, and pure Zr. Comparisons with concentration measurements made by nuclear reaction analysis allow one to affirm that for all the materials investigated here the phase shift measured by SMM is proportional to the oxygen concentration dissolved into the metal. Calibration functions are proposed for each material and frequency used. After calibration, the SMM can be used to measure local enrichments.