The effect of Co-Sn addition during liquid phase sintering on liquid film migration has been investigated in Mo-Ni. In Group 1 experiment, 95Mo-5Ni(Wt.%) specimens were sintered at 1460℃ for 12h and heat treated at 1460℃ for 2h after addition of Co-Sn powder mixture. With the increase and decrease of Sn content from 50 at.% in the mixture, the migration distance of liquid film increased. When the Sn content is 50 at.%, the migration did not occur. In group 2 experiment, 95Mo-5Ni specimens were sintered at 1460℃, 1540℃ and 1600℃ for 20h and heat treated at 1460℃ after addition of 1.6 wt.% Co. In the specimen initially sintered at 154℃, the boundary did not migrate, however, the migration occured in the specimens initially sintered at 1460℃ and 1600℃. These behaviors of liquid film migration could be explained by coherency strain energy which can exist in the thin diffusion layer of retreating grain. Chemical free energy difference between reprecipitated and dissolving materials could not explain the result of the experiments.
