Preliminary study for the evaluation of a pulsed coaxial plasma gun for removal of iron rust stain from bone artifacts

The pulsed coaxial plasma gun is an effective and fast way to remove stains found on the surface of cultural heritage materials. Invisible oil films, dust deposition, corrosion products, or other contaminants can be cleaned by plasma. Iron stain can be found on bone when it is in direct contact with the corroded iron object or in proximity to the corrosion products in the soil. This study aims to evaluate the removal of iron stain from the surface of bone by using Pulsed coaxial plasma. Different parameters of pulsed plasma have been evaluated to reach the best condition of the treatment. Pulsed coaxial plasma was applied to modern bone samples artificially stained with ferric hydroxides. Analytical techniques used to evaluate the iron stain removal were digital microscope, SEM-EDX, FTIR, color measurement by UV spectrophotometer, AFM, pH value, and contact angle measurement. The results indicated that the coaxial plasma is highly effective for iron stain removal and does not affect treated bones. The best cleaning was performed by pulsed argon plasma at 50 pulses, pressure of 0.2 mbar, 0.5 cm distance, and 3kV plasma power. (C) 2022 Elsevier Masson SAS. All rights reserved.

Automated summary

The pulsed coaxial plasma gun is an effective method for removing stains from cultural heritage materials, particularly iron stains. The study found that pulsed argon plasma was the most effective in removing iron stains.