This paper explores the possibilities of producing visually attractive cellular gold structures via two different powder metallurgical approaches: sintering of loosely packed gold fibers and replication of polymeric templates. In the latter case, two different templates were used: reticulated polyurethane (PU) foam and expanded polystyrene (EPS) spheres which were coated with atomized gold powder. In contrast to the fiber route, replication techniques require an intermediate thermal treatment for the removal of the templates prior to sintering. Typical carat gold alloys lend themselves for supersolidus liquid phase sintering due to a sufficient difference between solidus and liquidus temperature. This approach was applied to all three manufacturing routes and rigid cellular gold structures were obtained successfully in all cases.

Powder metallurgical manufacturing routes for cellular metals
Two different approaches were explored for obtaining highly porous cellular gold structures:

  • Sintering of gold fibers;
  • Replication of polymeric templates in the form of polyurethane (PU) sponges and expanded polystyrene (EPS) spheres.

The fiber structures and the replicated sponges were made from 18 ct. alloys while the hollow spheres were produced from a 14 ct. alloy. 

This article appeared in the March–April 2018 issue of Metal Powder Report. Log in to your free Materials Today account to download the full article.

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