Near-seamless joining of Cf/SiC composites using Y3Si2C2 via electric field-assisted sintering technique

A novel Y3Si2C2 material was synthesized at a relatively low temperature (900 V) using a molten salt method for the first time, and subsequently used as the joining material for carbon fiber reinforced SiC (C-f/SiC) composites. The sound near-seamless joints with no obvious remaining interlayer were obtained at 1600 degrees C using an electric field-assisted sintering technique (FAST). During joining, a liquid phase was formed by the eutectic reaction among Y3Si2C2, gamma(Y-C) phase, and SiC, followed by the precipitation of SiC particles. The presence of the liquid promoted the sintering of newly formed SiC particles, leading to their complete consolidation with the C-f/SiC matrix. On the other hand, the excess of the liquid was pushed away from the joining area under the effect of a uniaxial pressure of 30 MPa, leading to the formation of the near-seamless joints. The highest shear strength (z) of 17.2 +/- 2.9 MPa was obtained after being joined at 1600 degrees C for 10 min. The failure of the joints occurred in the C-f/SiC matrix, indicating that the interface was stronger than that of the C-f/SiC matrix. The formation of a near-seamless joint minimizes the mismatch of thermal expansion coefficients and also irradiation-induced swelling, suggesting that the proposed joining strategy can be potentially applied to SiC-based ceramic matrix composites (CMCs) for extreme environmental applications.

Automated summary

Y3Si2C2 material was synthesized at a low temperature and used as a joining material for C-f/SiC composites, resulting in near-seamless joints using an electric field-assisted sintering technique.