Development, and characterisation of ultra-high-temperature ceramics composite (UHTC)

Abstract

ABSTRACT Ultra high-temperature ceramic (UHTC) composite materials are physically and chemically stable at high temperatures (more than 2000°C) and in reactive environments. Generally, the family group of diboride, dicarbide, and dinitride are used as ultra-high temperature ceramic due to their high thermal conductivity and high melting point. The main aim of this paper is the development of zirconium diboride (ZrB2)-based UHTC and characterisation of their density, hardness, porosity, and work considered, three powder constituents B4C (35%), ZrB2 (55%), and Cr (10%) of particle size 30 μm, 15 μm, and 4 μm, respectively, the conventional sintering and spark plasma sintering technique is used for the development of composite. The results revealed that the relative density of conventionally sintered composite at 1600°C and 1700°C are 72% and 80%, respectively, and spark plasma sintered composite at 1900°C is 99.99%. The bulk density and apparent porosity of SPS composite at 1900°C are 4.73 g/cm3 and 4%, respectively. Similarly, bulk density and apparent porosity of conventionally sintered composite, at 1600°C are 2.49 g/cm3 and 30%, respectively, and at 1700°C is 2.89 g/cm3 and 27%, respectively. Furthermore, the hardness of the SPS composite at 1900°C is 2830 HV, while the hardness of conventionally sintered composite at 1700°C and 1800°C were 280 HV and 520 HV, respectively. Additionally, scanning electron microscopy was performed to observe the bonding and porosity in the microstructure of the UHTC.