Hot Pressing of Tantalum Carbide With and Without Sintering Additives

Abstract

Densification of tantalum carbide (TaC) was studied by hot pressing at temperatures ranging from 19001 to 24001C with and without sintering additives. Without sintering additives, the relative density increased from 75% at 19001C to 96% at 24001C. A microstructural examination showed no observable grain growth up to 23001C. Densification was enhanced with carbon (C) and/or B 4 C additions. TaC with a 0.78 wt% C addition achieved a relative density of 97% at 23001C. Additions of 0.36 wt% B 4 C or 0.43 wt% B 4 C and 0.13 wt% C increased the relative density to 98%

Graphene NanoPlatelets reinforced tantalum carbide consolidated by spark plasma sintering

“…Hot pressing (HP) has been reported to be one of the most effective techniques for obtaining high density UHTCs [22,44,47,58,59]. Ta [30].…”

Microstructure and Mechanical Properties of Nanofiller Reinforced Tantalum-Niobium Carbide Formed by Spark Plasma Sintering

“…Tantalum Carbide, as well as other UHTC materials such as NbC, VC, and HfC, has been consolidated into bulk form using various processing approaches (outlined in Table 3) including hot pressing [26][27][28][29][30][31], pressureless sintering [32,33], vacuum plasma spraying [34], high frequency induction heating [35,36], and spark plasma sintering [37][38][39][40]. Differences in heating and cooling rates, temperatures, dwell times, and pressures will impact the phase formation, microstructures, and densification of the final product.…”

“…Densification of a non-oxide ceramic, such as TaC, has been enhanced by adding free carbon or B 4 C which act as reducing agents that react with sintering inhibiting oxide impurities, such as Ta 2 O 5 , on the particle surfaces [30]. Sintering additives can also enhance densification by physically pinning grains to mitigate grain growth and reduce the possibility of trapped porosity.…”

“…Other sintering additives that have previously been shown to enhance densification while better maintaining the high temperature properties of the ceramic include carbon, TaB 2 , TaSi 2 , MoSi 2 , SiC, B 4 C, and Si [28,30,31,33,37,39].…”

“…It involves the slow application of heat and uniaxial pressure to allow significant plastic flow of the material to increase relative densification. Zhang et al [29,30] achieved 94% relative densification of TaC by hot pressing at 2300°C for 45 minutes with a pressure of 30 MPa. When the temperature was increased to 2400°C, the relative densification increased to 96% but saw an increase in average grain size from 1.6 µm to 2.8µm ( Figure 6).…”