Cross-diffusion phenomena within a ZrC_x – Zr – ZrC_x joint

This study uncovers process conditions for the homogenization of the interface zone formed by a diffusion bonding of ZrC_x (x = 1, 0.85 and 0.7) assisted by a Zirconium interlayer. The transitional metal interlayer is positioned between the ceramics mating surfaces _. The ability of Zr to form a homogenous joint with ZrC_x was verified for all the considered cases of ZrC_x. The homogenous joint domain forms under conditions of a particular range of values of (i) the concentration of carbon vacancies in the base ZrC_x ceramics, (ii) the bonding temperature, and (iii) the holding time, for a given thickness of the interlayer. The formation of a homogenous domain improves remarkably the mechanical properties of ZrC_x joints. It is established that the four-point bending strength and the nano-indentation hardness of the homogenous ZrC_x/Zr/ZrC_x joints can be as high as that of the base ceramics.