Microstructure of ZrB₂–ZrN directionally solidified eutectic composite by arc-melting

A ZrB2–ZrN eutectic composite was prepared by arc-melting a mixture of ZrB2 and ZrN powders under a N2 atmosphere. The eutectic composition was 48ZrB2–52ZrN (mol%), resulting in a rod-like microstructure comprising hexagonally faceted ZrN single-crystal rods dispersed in a ZrB2 single-crystal matrix. The crystal orientation relationship between the ZrB2 matrix and the ZrN rod was ZrB2 $$\left\{ {11\bar 20} \right\}$$//ZrN{101} and ZrB2 <0001>//ZrN <111>. The rod-like eutectic composite had a Vickers hardness of 16.2 GPa.