Quantitative description of microstructure defects in hexagonal boron nitrides using X-ray diffraction analysis

• Reliable method for quantification of microstructure defects in BN was suggested.
• The method is based on the analysis of anisotropic XRD line broadening.
• This XRD line broadening is unique and characteristic of the respective defect.
• Thus, the quantification of coexistent microstructure defects is possible.
• The method was tested on hexagonal BN, which was produced by different techniques.

A routine for simultaneous quantification of turbostratic disorder, amount of puckering and the dislocation and stacking fault density in hexagonal materials was proposed and tested on boron nitride powder samples that were synthesised using different methods. The routine allows the individual microstructure defects to be recognised according to their effect on the anisotropy of the X-ray diffraction line broadening. For quantification of the microstructure defects, the total line broadening is regarded as a linear combination of the contributions from the particular defects. The total line broadening is obtained from the line profile fitting. As testing material, graphitic boron nitride (h-BN) was employed in the form of hot-isostatically pressed h-BN, pyrolytic h-BN or a h-BN, which was chemically vapour deposited at a low temperature. The kind of the dominant microstructure defects determined from the broadening of the X-ray diffraction lines was verified by high resolution transmission electron microscopy. Their amount was attempted to be verified by alternative methods.