Pulsed electric current sintering of TiB2-based ceramics using nitride additives

Naeimeh Sadat Peighambardoust,Seon Yong Lee,Tannaz Assar,Sunghoon Jung,Çağın Çevik,Joo Hwan Cha

doi:10.53063/synsint.2021.1112

Abstract

In this research, various types of nitride additives were incorporated into titanium diboride attaining dense TiB2-based ceramics by field-assisted sintering technique. The addition of different types of nitride additives, namely Si3N4, BN, AlN, and TiN, significantly improved the sinterability of TiB2, achieving near fully dense ceramics. The X-ray diffraction analysis and microstructural evaluation confirmed the presence of the h-BN compound in all specimens. In the TiB2-Si3N4 ceramic, Si3N4 additive reacted with B2O3 oxide, in-situ generating h-BN, and SiO2 phases. Although the h-BN phase was produced in the TiB2-AlN specimen, the main proportion of AlN remained in the sample as an unreacted ex-situ phase. In terms of the TiB2-TiN ceramic, some of the nitrogen and boron atoms could leave the TiN and TiB2 crystalline structures, contributing to the in-situ formation of h-BN.

Highlights

As an ultra-high-temperature ceramic (UHTC), TiB2 possesses many magnificent advantages, such as high melting point, great hardness, good wear resistance, good thermal conductivity, high Young’s modulus, and relatively low coefficient of thermal expansion [1,2,3,4,5]
Identifying no peak except the base materials in all X-ray diffractometer (XRD) patterns indicates the high-purity of the aspurchased powders
As can be seen in this bar chart, the monolithic TiB2 hit a relative density of 94.9%, which implies more than 5% remaining porosity in the undoped ceramic

Summary

Introduction

As an ultra-high-temperature ceramic (UHTC), TiB2 possesses many magnificent advantages, such as high melting point, great hardness, good wear resistance, good thermal conductivity, high Young’s modulus, and relatively low coefficient of thermal expansion [1,2,3,4,5] Having such diverse features has made TiB2 an appropriate candidate for several applications, including armors, cutting tools, turbine blades, Hall-Heroult cells’ cathodes, abrasion, and corrosion resistance compounds, etc. The composite sample reached its near fully dense density, manifesting the beneficial role of AlN as a sintering aid Both microstructural observations and XRD patterns verified the in-situ formation of the h-BN ingredient owing to a chemical reaction between the introduced AlN and the surface oxide of B2O3. The SPS process was implemented to fabricate the targeted specimens, and subsequently, the SPSed samples were characterized using XRD and FESEM

Methods

Results

Conclusion