Feedstock Selection

The idea of using metal particulates for consolidation into useful product forms has been explored for ages, before furnaces were developed that could exceed the melting point of metals. A classical example is the sponge iron used by the Egyptians around 3000 B.C. for making tools. Since the beginning of modern powder metallurgy in the 19th century, initiated by producing compact platinum from platinum sponge powder, the role of metal powders has experienced a continuous increase. Today, powder metallurgy represents well-established industrial technology, providing not only high quality intricate shapes, but also unique material microstructures. As opposed to particulates with tens or hundreds of micrometers, required in powder metallurgy, relatively coarse ones with a size of the order of several millimeters have been used for decades in a variety of chemical, pharmaceutical, military and metallurgical applications. The latter type became a precursor of the feedstock for injection molding. The particulates are also called chips, granules or pellets, depending on their shape and manufacturing technique. So far, the material choice is restricted to low-melting point alloys—mainly to Mg-based, Zn-based and Al-based compositions.