High-strength SiC joints fabricated at a low-temperature of 1400°C using a novel low activation filler of Praseodymium

High-strength SiC joints were successfully obtained by electric current field-assisted sintering technique at a low temperature of 1400 degrees C using a Pr coating (100 nm) as the initial joining filler. A Pr3Si2C2 transient phase was formed in situ by the interfacial reaction, while the eutectic reaction between Pr3Si2C2 and SiC at similar to 1150 degrees C resulted in the formation of a liquid phase. The liquid phase promoted the atomic diffusion at the interface and improved consolidation of the newly precipitated nano-sized SiC with the SiC matrix. This led to the formation of partially seamless joints of SiC. When the thickness of the joining layer decreased from 1 to 100 nm, the content of the residual Pr-O phase at the interface decreased, while the bending strength of the joints increased. A sound SiC joint with a bending strength of 227 +/- 12 MPa was obtained at such a low temperature as 1400 degrees C when a 100 nm Pr coating was applied.

Automated summary

High-strength SiC joints were successfully obtained using a Pr coating as the initial joining filler and electric current field-assisted sintering technique at a low temperature of 1400 degrees C. The formation of a Pr3Si2C2 transient phase and a liquid phase between Pr3Si2C2 and SiC promoted atomic diffusion at the interface and improved consolidation, resulting in partially seamless SiC joints. The bending strength of the joints increased with the decrease in joining layer thickness, reaching a value of 227 +/- 12 MPa with a 100 nm Pr coating at 1400 degrees C.