Abstract
Powder metallurgical preforms, which were fabricated by compaction and sintering as well as by loose sintering, were subjected to surface densification as a secondary operation by means of a specially designed indenter. The resulting structure of each specimen consisted of three zones, namely a fully dense layer, an intermediate zone with gradually increasing porosity, and the initial porous core that did not undergo any densification. Such a unique structure was created to mimic natural bones and the potential application for such parts would therefore be bone implants. The morphology of various specimens was characterised using image analysis with optical microscopy, physical measurements of density distribution, as well as scanning electron microscopy. Results indicated that the thickness of the fully dense layer increased with increasing depth of indentation and can be controlled as required.