Sinterability of Nano-Sized Silicon Carbide Powders

Abstract

The sinterability of three kinds of commercially available nano-sized SiC powders and a treated nano-sized SiC powder was investigated using Al 2 O 3 -Y 2 O 3 -CaO as a sintering additive. The commercially available, as-received nano-sized SiC powders were difficult to sinter to a relative density of 95! by conventional hot pressing. The effects of the free carbon and SiO 2 impurities in the starting powders on the sinterability of the nano-sized SiC powders were identical to those on the submicron SiC powders. However, both the extremely high free carbon content and low green density of the commercially available nano-sized SiC powders were responsible for their poor sinterability. The reduction of the free carbon content by oxidation and the control of the SiO 2 content by acid treatment were beneficial for enhancing the sinterability of the nano-sized SiC powder during liquid-phase sintering.

Effects of carbon and oxygen on the spark plasma sintering additive-free densification and on the mechanical properties of nanostructured SiC ceramics

“…The higher coefficients could be caused by the presence of silicon excess which has high oxygen affinity. Lower E ox coefficients (1 to 2.5) were only found for powders showing an excess of carbon [3,30,31]. The E ox coefficient of SiC-C nanopowder (2.2) is similar to the E ox values of those latter powders and suggests that oxygen content is low for such SSA.…”

Effect of carbon nanofibers (CNFs) content on thermal and mechanical properties of CNFs/SiC nanocomposites

“…In order to broaden the range of its practical application, fracture toughness of SiC needs to be improved to an acceptable level. In the last years, LPS-SiC derived from SiC nano-power as a starting material has been in the spotlight all over the world due to its excellent sinterability at the lower temperature [11,12]. Nano-infiltration and transient eutectic-phase (NITE) process has been developed for the production of highly dense and crystallized SiC/SiC composites at Kyoto University [13][14][15][16].…”

Surface oxidation and dispersion behaviour of phenolic resin coatedα-SiC powder in aqueous medium

“…The absence of transmittance bands near 490 cm 21 for both treated and untreated RSC powders ( Fig. 6(C) and (D)) clearly suggests that the phenolic resin restricting some of the vibrations of SiC, which are responsible for band at 490 cm 21 . The vibrations of 2OH groups of phenol cause transmittance band between 1410 and 1310 cm 21 .…”

“…by liquid phase sintering). [19][20][21] However, these liquid phase sintered products are known for their inferior corrosion resistance and poor hardness as they contain intergranular phases. On the other hand, the solid state sintered SiC parts with boron and carbon exhibit high specific stiffness (Young's modulus/density) and superior thermal stability (thermal conductivity/coefficient of thermal expansion), which make them suitable for certain important applications.…”