Microstructure and Mechanical Properties of TiN–TiB2–hBN Composites Fabricated by Reactive Hot Pressing Using TiN–B Mixture

Abstract

In this study, TiN–TiB2–hBN composite ceramics were prepared via reactive hot pressing using TiN and amorphous B powders as raw materials. Different sintering temperatures and composition ratios were studied. The results show that the 70 vol% TiN–17.6 vol% TiB2–12.4 vol% hBN ceramic composites obtained ideal comprehensive properties at 1600 °C. The relative density, Vickers hardness, bending strength, and fracture toughness were 99%, 11 GPa, 521 MPa, and 4.22 MPa·m1/2, respectively. Densification was promoted by the highly active reaction product TiB2, and the structural defects formed in the grains. Meanwhile, the good interfacial bonding between TiN and TiB2 grains and the uniform dispersion of ultrafine hBN in the matrix contributed to the excellent bending strength. Moreover, the toughening mechanism of crack deflection and grain pull-out improved the fracture toughness.

The Influence of Molasses Concentration on the Physical and Mechanical Properties of Evaporation Boat Waste-Based Crucibles

“…Boron nitride (BN) and titanium diboride (TiB2) have remarkable properties such as outstanding resistance to wear, great hardness, stability at high temperatures, and a high melting point. This makes it easier to use BN and TiB2 in many industrial processes, such as metallic evaporation plating, wear-resistant coatings, and aerospace applications [9][10][11]. Composite ceramics made of TiB2 and BN are good at conducting electricity, resist wear well, and are easy to machine [10,12].…”