Production of sponge cast aluminum by liquid phase sintering of NaCl-KCl mixtures

Abstract

Sponge cast aluminum alloy (SCA) can be produced by a new process where NaCl particles are sintered first, molten aluminum is forced to fill the pores of the sinter, and then NaCl is dissolved away from the NaCl-Aluminum composite in the water. The liquid phase sintering of NaCl particles covered with fine KCl powders has the advantages of lowering the sintering temperature and saving the sintering time, because KCl can decreases the melting temperature of NaCl through reaction and has a wide range of solid-liquid coexistance in its phase diagram. Another advantage of liquid phase sintering is the high permeability of the resulting SCA. The reason for this is thought that the liquid phase gets together at the contact points of NaCl particles leading to the wide connection of NaCl particles each other.