DETERMINATION OF SMALL CONCENTRATIONS OF HAFNIA IN ZIRCONIA BY SELECTIVE EXCITATION-ENERGY DISPERSIVE-X-RAY EMISSION-SPECTROMETRY

An energy dispersive X-ray fluorescence method is described for the de termination of small concentrations of hafnia in zirconia. Bromine K X -rays from a secondary target in the form of a thick KBr pellet (excit ed by primary X-rays from a tungsten target X-ray tube) have been used to excite the analyte Hf L-lines selectively without exciting the mat rix Zr K X-rays. The Hf Lalpha intensity vs. concentration relation wa s found to be linear in the concentration range 0.0 - 2.0 percent. The method gave a minimum detection limit of 45 ppm for 10 min (live) cou nting time. The results are discussed and the performance of this meth od is compared with those of WDXRF methods.