AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP29
Hydrogen Desorption from Acid Attacked Titanium after DC Glow-discharge Treatment

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: B.-O. Aronsson, University of Geneva, Switzerland
Authors: B.-O. Aronsson, University of Geneva, Switzerland
B. Hjorvarsson, Royal Institute of Technology, Sweden
P. Descouts, University of Geneva, Switzerland
Correspondent: Click to Email
Thermal desorption (TD) of hydrogen (H) from an acid attacked titanium (Ti) surface has previously@footnote 1@ been shown to depend on the presence of a surface oxide. The oxide was removed from Ti surfaces by using a DC glow-discharge (Ar plasma) treatment, and the subsequent change in the TD of absorbed H was studied. Biocompatibility is influenced by both surface chemical and topographical properties. In this study, the surface roughness of c.p. Ti samples was increased by at least a factor of 50 as measured by AFM.@footnote 1@ However, beside topographical modifications, acid attack also gives a dissolution of atomic H into the Ti sub-surface region and bulk which may result in a modification of the mechanical properties. Earlier work showed that TD above 400°C, where the oxide decomposes, is needed for H desorption.@footnote 1@ At these temperatures the morphology and mechanical properties of the Ti bulk are also modified and a lowering of the desorption temperature is desired. After plasma treatment the TD started below 300°C and the desorption activation energy was decreased from ca 2.0 (±0.3) to 0.8 (±0.2) eV/molecule. Ar plasma treatment was found to be efficient for a homogeneous sputter cleaning (characterized with AES), even of surfaces with a high surface roughness, and the native oxide was removed. The total amount of thermally desorbed hydrogen was inversely related to the plasma treatment intensity, while NRA profiles showed a complete elimination of the subsurface hydrogen after a medium intensity plasma treatment. AFM and SEM were used to characterize the topographical modification of plasma treated surfaces.@footnote 2@ @FootnoteText@ (1) Taborelli, M., et.al., Clinical Oral Implants Research, 1997, 8, 208-216 (2) Support from the ITI Foundation for the promotion of oral implantology, Switzerland, and from the Swiss National Fund, are greatly acknowledged.