TY  - JOUR
AU  - Zhong, Lianbing
AU  - Liu, Limeng
AU  - Worsch, Christian
AU  - Gonzalez, Jesus
AU  - Springer, André
AU  - Ye, Feng
TI  - Transient liquid phase sintering of tantalum carbide ceramics by using silicon as the sintering aid and its effects on microstructure and mechanical properties
JO  - Materials chemistry and physics
VL  - 149-150
SN  - 0254-0584
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2016-00481
SP  - 505 - 511
PY  - 2015
AB  - Tantalum carbide composites with 0.76–8.85 wt.% elemental silicon as a sintering aid were fabricated by spark plasma sintering (SPS) at 1700 °C and 30 MPa for 5 min. The transient-liquid-phase sintering behavior, the microstructures and the mechanical properties of the tantalum carbide composites were investigated. Oxide impurities present on the surfaces of the tantalum carbide particles were eliminated by reactions with the elemental silicon in a temperature range from 1271 °C to 1503 °C to benefit densification. Then the silicon melted at its melting point temperature of 1413 °C to facilitate rearrangement of the tantalum carbide particles. By the end of the densification, the elemental silicon transformed into more refractory TaSi2 and SiC in the consolidated ceramics by reactions with the tantalum carbide at temperatures lower than 1773 °C. Both TaSi2 and SiC particles improved densification by physically pinning growth of the tantalum carbide grains. Further densification was resulted from creep flow of the silicides after brittle-to-ductile transformation of the silicides at temperatures <1650 °C. Due to the good effects of using elemental silicon as the sintering aid, all the compositions reached densities >96.7% theoretical. The average grain sizes in the consolidated materials decreased with the silicon addition from about 19 μm in the 0.76 wt.% Si composition to about 9 μm in the 8.85 wt.% Si composition. A good flexural strength up to ∼709 MPa was reached in the 8.85 wt.% Si material due to full density and fine microstructure.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000347576900070
DO  - DOI:10.1016/j.matchemphys.2014.10.052
UR  - https://juser.fz-juelich.de/record/280724
ER  -