The structure and mechanical properties of AlN–C–ZrB2 composite ceramics for electrical applications, based on AlN with 2 wt % diamond powder and 8–13 wt % ZrB2, sintered by hot pressing at 1920°C under 20 MPa, were investigated. Scanning electron microscopy and X-ray diffraction, with Rietveld analysis of diffractograms, revealed that composites with varying initial ZrB2 content consist of the main phases AlN, Al3(O,N)4, ZrB2, ZrC, Y3Al5O12, and carbon in the form of graphite. Mechanical testing showed that Vickers hardness at an indenter load of 9.8 N reaches 11.44 ± 0.53 and 12.18 ± 0.30 GPa for samples with 8 and 13% initial ZrB2, respectively. Cracking from the corners of the pyramid imprint was observed at a load of 49 N, with fracture toughness values ranging from 6.03 to 6.36 MPa m1/2.
Сербенюк et al. (Wed,) studied this question.