Effects of Pulse Current on an Aluminum Powder Oxide Layer During Pulse Current Pressure Sintering

Abstract

The pulse current pressure sintering and hot press process were applied for sintering of aluminum powder produced by water and gas atomizing methods. The pulse current pressure sintering process could densify the water atomized powder in a short time compared with the hot pressing because it could remove the H₂ gas at lower temperature. The gas prevents sintering of aluminium powder. The tensile strength of the pulse current pressure sintered gas atomized powder which contains low H₂ was higher than that of hot pressed specimen. The electric resistivity of sintered specimens obtained by pulse current pressure sintering process was lower than that of hot pressed specimen. The oxide layer destruction was confirmed by this measurement of electric resistivity. The oxide layers were supposed to be fractured by the high temperature region which is attributed to Joule heat by contact resistance.