4. Concluding remarks
We have described an investigation of the oxidation of ZrB2 powders during their high-energy ball-milling in air, using various analytical techniques.
The direct measurement of the oxygen content by the IGF method revealed that the powders subjected to high-energy ball-milling in air are twice as rich in oxygen
as those subjected to the more conventional attrition milling.
The XRD analyzes, including detailed Rietveld refinements, showed that the captured oxygen does not form solid-solutions but amorphous oxides.
The density measure ment by helium pycnometry confirmed the formation of such oxides,
and was entirely consistent with the phase composition determined by IGF and XRD.
The XPS analyzes indicated that these amorphous oxides are ZrO2 and B2O3,
something that could not be determined by the FTIR or Raman spectroscopy,
and that they locate preferentially on the surface of the powder particles,
in perfect agreement with the direct TEM observations.
4. Concluding remarksWe have described an investigation of the oxidation of ZrB2 powders during their high-energy ball-milling in air, using various analytical techniques. The direct measurement of the oxygen content by the IGF method revealed that the powders subjected to high-energy ball-milling in air are twice as rich in oxygen as those subjected to the more conventional attrition milling. The XRD analyzes, including detailed Rietveld refinements, showed that the captured oxygen does not form solid-solutions but amorphous oxides. The density measure ment by helium pycnometry confirmed the formation of such oxides, and was entirely consistent with the phase composition determined by IGF and XRD. The XPS analyzes indicated that these amorphous oxides are ZrO2 and B2O3, something that could not be determined by the FTIR or Raman spectroscopy,and that they locate preferentially on the surface of the powder particles, in perfect agreement with the direct TEM observations.
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