REACTIVE HOT PRESSING OF B4C-CrB2 CERAMICS AND ITS MECHANICAL PROPERTIES

AbstractCeramic composites based on B4C with a CrB2 mole fraction of 0-30% were obtained by reactive hot pressing of a mixture of B4C, Cr2O3, and nanofibrous carbon at a uniaxial pressure of 17.5 MPa and a temperature of 2000 degrees C for 10 min. The possibility of boron carbide reduction of metal oxide during hot pressing was studied. During the synthesis of CrB2, the density of B4C was found to increase due to the formation of the CrB2-B4C eutectic liquid phase. The relative density of all B4C-CrB2 composites obtained under these conditions exceeds 90%. Experimental dependences of the microhardness and elastic modulus of samples on the concentration of the CrB2 plastic phase were obtained. The dependences of the elastic modulus of the heterogeneous material on the volume fraction of chromium diboride were determined taking into account porosity by sequentially using the Reuss and Voigt averaging schemes.