Pressureless Sintering of Tantalum Carbide Ceramics without Additives

Using fine tantalum carbide (TaC) powder with narrow particle-size distribution, monolithic TaC ceramics with a relative density of 97.5% was obtained by pressureless sintering at 2300 degrees C without adding additives. The monolithic TaC ceramics had a very fine microstructure with grain size of about 2 mu m. It is considered that the small particle size and uniform particle-size distribution of TaC powder are important factors for preparing dense TaC ceramics with fine microstructure. Otherwise, fast grain growth of TaC will occur. Compared with the reported values in literature, the monolithic TaC ceramics obtained demonstrated a high bending strength of 338 +/- 10 MPa.