Densification of high-strength B 4 C–TiB 2 composites fabricated by pulsed electric current sintering of TiC–B mixture

Synthesis and properties of conductive B4C ceramic composites with TiB2 grain network

“…Table summarizes the properties of the obtained ceramic composites in this work and previous reports . Although the thickness of coating varied with a decrease in the molar ratios (B 4 C/Ti), the relative densities were about 98% for all compacts at 1700°C.…”

“…As a comparison, the S2‐1700 with 29.8 vol% TiB 2 had a higher hardness and a lower fracture toughness than that of B30T, which was attributable to the sintering temperature and average particle size of B 4 C (B30T 3.5 μm and S2‐1700 10 μm). The B41T was in situ synthesised by PECS at 1900°C for 7 minutes, in which the average grain sizes of both B 4 C and TiB 2 were <1 μm. However, the relative density and fracture toughness of B41T were 97.9% and 4.4 MPa·m 1/2 , respectively, which were close to that of S2‐1700 with 29.8 vol% TiB 2 .…”

“…The relative density of TiB 2 ‐B 4 C material reached 98.2% of theoretical density, which was sintered by HPS at 1950°C for 60 minutes in vacuum with a pressure of 30 MPa . As a comparison, near fully dense (97.9%) the B 4 C‐41 vol% TiB 2 composite obtained by PECS at 1900°C for 7 minutes under a load of 50 MPa has a Vickers hardness of 28 GPa and a fracture toughness of 4.4 MPa·m 1/2 …”

“…Many previous reports have shown that B 4 C‐TiB 2 composites have the high fracture toughness, high flexural strength, high hardness, and low electrical resistance In this regard, TiB 2 can improve the mechanical properties and machinability of B 4 C as a sintering aid. B 4 C‐TiB 2 composites were sintered by frequently‐used sintering techniques, such as pressureless sintering (PLS), hot‐pressed sintering (HPS), and pulsed electric current sintering (PECS) . For these techniques, PECS has decided advantages over PLS and HPS.…”

“…Generally, B 4 C‐TiB 2 composites were prepared via in situ reaction of TiO 2 , carbon and B 4 C, from elemental powders, from TiB 2 and B 4 C, or from TiC and amorphous B powders . Among these reports, the homogeneous dispersion of raw materials was obtained by the ball‐milled method, which was time and energy consuming. This study aims to overcome the 2 disadvantages in B 4 C consolidation by molten‐salt method to form a uniform conductive coating on the surface of B 4 C particles without co‐ball milling.…”