The grain-boundary diffusion of 63Ni in polycrystalline Cu was investigated by using the radiotracer technique at 476 to 1156K. Independent measurements in the C and B kinetic regimes resulted in direct data on the grain-boundary diffusivity, Dgb, and on the triple-product, sδDgb. Arrhenius-type temperature dependences were found for both:

Dgb(m2/s) = 6.93 x 10-7exp[90.4(kJ/mol)/RT]

sδDgb(m3/s) = 1.89 x 10-16exp[73.8(kJ/mol)/RT]

Although Ni was completely soluble in Cu, it exhibited a distinct but moderate ability to segregate to Cu grain boundaries; with a segregation enthalpy of about 17kJ/mol.

S.Divinski, J.Ribbe, G.Schmitz, C.Herzig: Acta Materialia, 2007, 55[10], 3337-46