Effects of pore microstructures on thermal and mechanical properties of porous TiC fabricated by hot press sintering

Abstract

The porous TiC ceramics with different porosity were fabricated by hot-press sintering using CaO as pore-forming agent, which opened a new field to explore pore ceramics. Then a serious of porous TiC were fabricated and investigated the microstructure, porosity and mechanical properties of pore TiC. The porosity and bulk density of TiC depend on CaO content, which significantly affects the microstructure, mechanical properties and fracture behaviors. With the CaO content increasing, the porosity and pore size of TiC are increased, while the bulk density is decreased. Compressive strength and specific compressive strength exhibit a trend of monotone variation, and the maximum compressive strength is 51.3 MPa when CaO content is 40 vol%. A high porosity condition leads to a loose structure with low load-bearing capacity. As CaO content increases from 40vol% to 55vol%, porosity of TiC increases from 32.9 to 52.6%, and the compressive strength of porous TiC decreases from 51.3 MPa to 9.7 MPa. Additionally, it was concluded that porosity determine the bulk density and strength of porous TiC. However, the thermal conductivity of pore TiC increases with rising of porosity. This is attributed to the total number of pores is decrease owing to CaO agglomeration.