Densification, Mechanical Properties, and Oxidation Resistance of TaC-TaB2 Ceramics
The densification of tantalum carbide (TaC) was enhanced by adding 10 wt% (11 vol%) TaB2, reaching 98.6% relative density by hot pressing at 2100° or 2200°C using a 30 MPa applied pressure. X-ray diffraction analysis identified two phases, TaC and tantalum diboride (TaB2), with no peak shifts, indicating a solid solubility was not significant at these temperatures. Mechanical properties were measured for TaC-10 wt% (11 vol%) TaB2 hot pressed at 2100°C and compared with monolithic TaC hot pressed at 2300°C. The Young's modulus increased from 472 GPa for monolithic TaC to 543 GPa for TaC with 10 wt% (11 vol%) TaB2 additions. Vickers' hardness increased from 14.1 to 19.4 GPa. Fracture toughness values were comparable, in the range of 3.4-3.5 MPa·m1/2. The average flexure strength was 600 MPa, comparable to the flexure strength of monolithic TaC (686 MPa). Thermal gravimetric analysis indicated that the TaC-10 wt% (11 vol%) TaB2 oxidized at a slightly higher temperature than monolithic TaC. Together, the results indicate that TaB2 is an effective sintering aid for the densification of TaC.
X. Zhang et al., "Densification, Mechanical Properties, and Oxidation Resistance of TaC-TaB2 Ceramics," Journal of the American Ceramic Society, John Wiley & Sons, Dec 2008.
The definitive version is available at http://dx.doi.org/10.1111/j.1551-2916.2008.02780.x
Materials Science and Engineering
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