W. Ensinger et Hr. Muller, SURFACE MODIFICATION AND COATING OF POWDERS BY ION-BEAM TECHNIQUES, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 188(1-2), 1994, pp. 335-340
Powdered materials are widely used in industry. Many of the properties
of powders are determined by their surface. Therefore, surface modifi
cation techniques such as those based on ion beams are promising techn
iques for powder modification. Ion beam techniques are typical line-of
-sight processes. Only that part of a powder particle which is turned
directly towards the source of the ion beam and is not shaded is treat
ed properly. This renders uniform surface treatment of powders difficu
lt. More or less sophisticated facilities for agitating the powder in
the ion beam have to be used. In the present paper, a set-up is descri
bed for ion beam treatment of powders based on a rotating drum with wi
ngs which move the powder grains through the ion beam line. The featur
es of this facility and the processes which take place in it during io
n irradiation of powders are discussed. As an example, results of ion
implantation and ion beam sputter deposition of gold onto alumina powd
er are presented. The amount of implanted or deposited gold, depending
on rotation speed of the drum and number and type of ions, was determ
ined using neutron activation analysis. The powder grain surfaces with
deposited gold atoms were inspected with electron microscopy in combi
nation with X-ray analysis.