Reaction products at the interface of IN-738/Si3N4 bond

The purpose of this study was to investigate the interface microstructure and reaction products morphology in solid state diffusion bonding of the silicon nitride/Ni-based superalloy (IN-738). Compounds such as Cr3Si, Ni31Si12, delta-Ni2Si and Cr3Ni2Si were identified. A precipitated zone which exists between the reaction products and IN-738 works as a diffusion barrier, the reactive elements of IN-738 seem to be almost blocked to contribute to the formation of Cr3Si, Ni-31 Si-12, delta-Ni2Si, and Cr3Ni2Si. The phenomenon of morphological instability was also explained by Wagner's model. The faceted phases Cr3Ni2Si and delta-Ni2Si showed an epitaxial growth along with the Si3N4 matrix.