Abstract
A ordered mixture was prepared by a coating of Ni ultrafine particles (average diameter DAva= 80 nm) onto a Pb particle (DAVe= 50 um), and elution behaviors of molten Pb from the ordered mixture were examined by a high-temperature microscope and a scanning electron microscope during heat treatment at various heating rates (1->1500 K/min) in flowing 5%H2-Ar.
The elution of molten Pb through Ni coatings occurred just above the melting point of Pb in all heating rates. However, solidified morphology of eluated Pb changed markedly with the heating rate as follows: droplet-like (10-20 μm, 1 K/min), column-like (0.5-2 μm, 10-100 K/min), and fiber-like (10-20 nm.>1500 K/min), crystals, respectively. From these results, it is presumed that the network formed by sintering of Ni ultrafine particles exists on the surface of the Pb particle.
