Recent developments such as metal injection moulding (MIM) have led
to a demand for much fner powders, with median sizes around 10 mm. We
refer to these as fne powders. For such PM materials as diamond tools and
tungsten carbide, it is quite normal to utilise powders with a median size
of around 1 mm. These could perhaps be described as ‘superfne’ but there
is no accepted terminology. This is also true of ‘nanopowders’ where the
median particle size is sub-micron, but whether a 0.5 mm powder is sensibly
classifed as a nanopowder is debatable. When sizes get down to 10–100 nm
(0.01–0.1 mm), the ‘nanopowder’ classifcation is clearly reasonable.