Correlations between the optical emission spectra and microstructure of microplasma coatings on aluminum 2024 alloy

The microplasma synthesis of the surface layers on aluminum alloy 2024 was studied by optical emission spectroscopy in situ. The evolutions of atomic line intensities in emission spectra and the properties of obtained coatings are discussed. The evolution in the chemical composition of plasma microdischarges and coatings layer structure in the light of previously obtained data on the dynamics of phase transformation by EPR and semi-quantitative X-ray analysis were compared. In the early stages of the synthesis of the plasma consists mainly of the substrate components, but with coating thickness increasing the electrolyte components become dominant. The formation of a dense layer enriched with α-Al2O3 requires specific conditions, which can be found from the changes in the emission spectra of microdischarges radiation.

► Optical emission of microdischarges during microplasma synthesis on 2024 alloy. ► Simple well-known alkaline-silicate electrolyte as a model system was chosen. ► Changes in coating microstructure correlate with plasma composition evolution.