Hydrogen atom cleaning of archeological artefacts

Diagnostics of the magnetized low-pressure hydrogen plasma jet: Molecular regime

“…5 Apart from this, atomic hydrogen sources have been utilized in surface treatment of iron archaeological artefacts to protect the artefacts after the excavation against postcorrosion without inducing any surface damage. 3,6 The research of hydrogen plasmas has also a direct bearing to controlled thermonuclear fusion project. Heating of the fusion plasma by injection of neutral beams produced by neutralization of negative ions from a negative deuterium ͑hydrogen͒ ion source has been suggested as a key technology to reach the plasma conditions needed for energy production by thermonuclear fusion.…”

“…13,14 It has been shown that the expanding cascaded arc plasmas have potential prospect in different application fields; e.g., using a cascaded arc as a light source for spectroscopy, 15 as a particle source for surface modification,13 silicon thin film deposition, 16 carbon thin film deposition 17 and passivation protection technique for archaeological artefacts. 6 Mostly noble gases are used to feed the arc plasma, but exceptionally molecular gases like H 2 and SF 6 are added. 19,20 The aim of this research is to develop a hydrogen radical source for the rising interest in hydrogen plasma applications.…”

Cleaning of iron archaeological artefacts by cascaded arc plasma treatment

“…This can indicate that already at a seeding fraction of 5% hydrogen in the plasma hydrogen is abundant. In a previous paper another explanation is argued [1]: the relation between the hydrogen fraction seeded in the source and the atomic hydrogen fraction downstream the plasma beam is not clear. Especially at a high hydrogen fraction, recirculating (molecular) background gas is mixed into the plasma beam and lowers the dissociation degree drastically.…”

“…The second is to prohibit any further corrosion. It has been argued in an earlier paper [ 1] that hydrogen plasma treatment of the artefacts is very effective for overcoming both problems. A short exposure (about 10 min) to a hydrogen plasma loosens the encrustation from the artefact and it can be removed with a simple tool like a scalpel.…”

Nonequilibrium plasma jet using a combination of an orifice and applied magnetic field

“…High quality diamond films can be grown in a hydrogen-diluted plasma due to the presence of atomic hydrogen [8]. Atomic hydrogen sources have been utilized in the surface treatment of iron archaeological artifacts to protect the artifacts against postcorrosion after their excavation without inducing any surface damage [9][10][11][12]. Hydrogen plasmas are generated at ambient pressure on the order of 100 Pa and an input power on the order of 100-1000 W.…”