Almost seamless joining of SiC using an in-situ reaction transition phase of Y3Si2C2

Abstract

A new design of seamless joining was proposed to join SiC using electric field-assisted sintering technology. A 500 nm Y coating on SiC was used as the initial joining filler to obtain a desired transition phase of Y3Si2C2 layer via the appropriate interface reactions with the SiC matrix. The phase transformation and decomposition of the transition phase of Y3Si2C2 was designed to achieve almost seamless joining of SiC. The decomposition of the joining layer to SiC, followed up by the inter-diffusion and complete densification with the initial SiC matrix, resulted in the formation of an almost seamless joint at the temperature of 1900 °C. The bending strength of the seamless joint was 134.8 ± 2.1 MPa, which was comparable to the strength of the SiC matrix. The proposed design of seamless joining could potentially be applied for joining of SiC-based ceramic matrix composites with RE3Si2C2 as the joining layer.