Hydrogen desorption from sand-blasted and acid-etched titanium surfaces after glow-discharge treatment

• Published in: Journal of biomedical materials research Vol. 54; no. 1; p. 20
• Main Authors: Aronsson, B O, Hjörvarsson, B, Frauchiger, L, Taborelli, M, Vallotton, P H, Descouts, P
• Format: Journal Article
• Language: English
• Published: United States 01.01.2001
• Subjects: Acids; Biocompatible Materials; Chemical Phenomena; Chemistry, Physical; Hydrogen - chemistry; Microscopy, Electron, Scanning; Prostheses and Implants; Scattering, Radiation; Surface Properties; Thermodynamics; Titanium - chemistry; X-Ray Diffraction
• ISSN: 0021-9304
• DOI: 10.1002/1097-4636(200101)54:1<20::AID-JBM3>3.0.CO;2-Z

Hydrogen desorption from argon plasma-treated titanium implants with a high surface roughness was studied. Implants with a high surface roughness have shown an increase in mechanical stability in bone tissue and a different behavior of osteoblasts in vitro. High surface roughness was produced by grit blasting and acid etching, resulting in an increase of the sub-surface hydrogen concentration and the formation of a titanium hydride. After an argon plasma treatment the surface oxide, which always covers titanum surfaces exposed to an oxygen-containing environment, and some of the hydrogen were sputtered away, decreasing the hydrogen concentration in the sub-surface region. Nuclear reaction analysis was used to determine the hydrogen concentration as a function of depth. The total amount of sub-surface (down to a depth of < or = 2 microm) hydrogen remaining after plasma treatment decreased with increasing plasma intensity to below the levels observed in non-acid-etched samples (approximately 1-2%). Thermal desorption spectroscopy was used for desorption studies and investigation of H(2) desorption activation energies. With a surface oxide present, the onset of hydrogen desorption is at ca 400 degrees C, which is the oxide decomposition temperature in vacuum, with an activation energy of ca 2 eV/molecule of H(2). After plasma treatment, that is, without surface oxide present, the onset of desorption was observed at ca 300 degrees C and with an activation energy of ca 0.8 eV/molecule of H(2), indicating a bulk diffusion-limited desorption.