Table 1 Solutions to long-standing complexities with TRIS-XRPD analysis for ball milling reactions.
Complexity | Proposed solution |
|---|---|
Sample scattering intensity and reliable XRPD refinement | • Low-energy radiation to reduce peak overlap • Minimise jar wall thickness to maximise sample scattering • Include experimental background (empty jar) in the PXRD data analysis by whole-pattern Rietveld refinement to minimise the number of background parameters • Use experimental background scale factor to normalise PXRD scans • Sequential approach to Rietveld refinement, i.e. use the output obtained for scan number “n” as input for scan number “n + 1” |
Instrumental broadening of diffraction profile | • Low-energy radiation to reduce peak overlap • Optimise beam alignment strategy to resolve multiple scattering components using a standard • Develop physically meaningful XRPD peak shape modelling for microstructural analysis • Include experimental background (empty jar) in the PXRD data analysis by whole-pattern Rietveld refinement to minimise the number of background parameters • Sequential approach to Rietveld refinement • Parametric refinement for phase scale factors, i.e. constrain scale factors to sigmoidal curves |
Scale of powder required for milling | • Minimise jar wall thickness to maximise sample scattering • Minimise powder caking |
Loss of free powder by sticking or caking on internal surfaces | • Carefully analyse loading vs milling parameters to maximise powder distribution |
