Deposition of alumina coatings on stainless steel by a combined laser/sol–gel technique

Fibre laser (wavelength 1064 nm) was employed to deposit sol–gel alumina coatings onto stainless steel substrates. The alumina coatings were applied on the surface of the substrates in wet conditions and then irradiated using fibre laser at various energies to precipitate the alumina coating from its sol–gel solution onto substrates. The results showed that the deposited alumina coating at laser energy density of 87 J/mm2 crystallised in γ-Al2O3; however, the increase of the laser energy density at 173.9 J/mm2 led to the deposition of α-Al2O3. Nano-indentation measurements demonstrate that the mechanical properties of laser-deposited alumina coatings in terms of hardness and Young's modulus are improved in comparison with as-dried alumina coating without laser irradiation.

► Alumina coatings were deposited on stainless steel via laser/sol–gel technique.
► The deposition was realised using a fibre laser to irradiate over alumina sol.
► The deposited alumina coatings crystallised in γ-Al2O3 and α-Al2O3.
► Hardness and Young's modulus values of Laser-deposited alumina coatings are improved.