Effect of electrostatic charged state on die-wall lubrication for powder metallurgy

This study was made to investigate the electrostatic adhesion of powder lubricants of various types caused by friction, and the resulting green compact and sintered compact characteristics when the powder lubricant was used as a die-wall lubricant. The powder lubricant like metallic soap containing a functional group that is easily polarized (carboxyl group) in the molecular framework is suitable for use as a die-wall lubricant by electrostatic adhesion. It was shown that the powder lubricant with finer particle size containing easily polarized functional group adheres to the die wall easily. It was also shown that density and transverse rupture strength of the sintered compact increase with increase of coverage of the die surface by the powder lubricant.