Abstract
Role of grain boundaries in high temperature sintering of fcc metals such as nickel and copper, i.e., the effect of the presence or the absence of grain boundaries on neck growth still remains obscure.
In order to clarify this problem, a series of experiments were carried out on nickel, by using various model compacts. This first paper describes the experimental results on 3 wire model compact.
Neck growth follows Kuczynski's 5th power relation for volume diffusion. Rate of approach of centers of wires was proportional to time to 2/5 power. The data of neck growth and shrinkage were analyzed by volume diffusion mechanism with vacancy sink at the neck grain-boundary. The obtained frequency factor for self diffusion was about 1 cm2/sec and the activation energy about 61 Kcal/mol in both cases, which are in good agreement with the reported values for self diffusion.
