X-ray Fluorescence Analysis of Y_3–xYb_xNbO₇ Paraniobate-Based Ceramics

A two-stage technique has been developed for X-ray fluorescence (XRF) analysis of Y_3–xYb_xNbO₇ (x = 0–3) rare-earth paraniobates, suitable for use as thermal barrier coating materials. In the first stage, a preliminary composition of ceramic samples and intermediate synthesis products was determined by rapid semiquantitative analysis using the fundamental parameter method. In the second stage, the quantitative composition of the samples was determined using calibration curves. To obtain the calibration curves, a series of reference samples containing 3.16–56.55 wt % Y, 8.78–71.0 wt % Yb, and 12.83–19.70 wt % Nb were prepared in the same way as the ceramic samples studied. We chose analytical lines free from spectral overlaps and optimized XRF analysis conditions (X-ray tube current and voltage, exposure time, and the way in which the background near analytical lines is taken into account). The relative standard deviation in the results of Y, Yb, and Nb determinations in the ceramic samples did not exceed 0.66% and the relative error was no greater than 1.63%. The results we obtained were compared to calculated percentages of the analytes in stoichiometric samples and to analytical data obtained for the ceramic samples by inductively coupled plasma optical emission spectroscopy. The proposed technique allows major components of ceramic samples to be determined and can be used for analytical monitoring of the rare-earth paraniobate synthesis process.