is widely applied in various fields of machinery, aircraft industry and
electrical engineering for protecting aluminum and its alloys parts from
corrosion, for increasing strength and wear resistance and for creating electrically
insulating layer on the part surface. An anodizing coating is a porous aluminum
oxide film obtained by anodic oxidation mainly in an acid and, sometimes, in an
Application of nanodiamonds in
anodic oxidation was firstly studied in the beginning of the century by L.
Bernhard, G. Burkat and V. Dolmatov. Specially modified negatively charged
nanodiamonds added to an electrolyte at anodizing move to the anode (aluminum
and its alloys) and penetrate into Al2O3 film and pores formed at the process.
Moreover, during the oxidation nanodiamonds adsorb facilitated hydrogen, which
results in the considerable decrease of porosity and high increase in the
coating density. The oxide film weight increases by the factor of 2–3.5. This
high density of the coating, as well as the incorporation of nanodiamonds into
the oxide film significantly improve the performance of the coating: corrosion
protection, insulating properties and especially wear resistance. The oxide
film wear reduces by the factor of 10–13.
The optimal nanodiamond content in an electrolyte is 2–15 gram per
liter. The obtained microhardness is 800 – 1200 kg/mm2. The best mechanical
properties are achieved at nanodiamond anodic oxidation when the electrolyte
temperature is 10 °C.
Aluminum alloy 16082 AlMgSi containing 0.7–1.3% Si,
0.5% Fe, 0.1% Cu, 0.4–1.0% Mn, 0.6–1.2% Mg, 0.25% Cr, 0.2% Zn, and 0.1% Ti; the
plate area 1 cm2