Oxygen diffusion hardening of cp-titanium for biomedical applications.
Common methods to increase the wear resistance of titanium by surface hardening in biomedical applications, such as chemical/physical vapour deposition techniques or thermal/electrochemical oxidation, result in a layer of titanium dioxide or titanium nitride on the metal surface with a sharp interface between the hard and brittle coating and the ductile metallic substrate. A major disadvantage of these methods is that the sharp transition in material properties may cause exfoliation of these coatings. In this work, a two-step heat treatment was used to investigate oxygen diffusion hardening and its capability to produce hard surfaces with a transition zone between the coating and the ductile substrate. During the first step, the native oxide layer was strengthened. In the second step, oxygen diffusion was activated and a transition zone was formed. Different methods of analysis confirmed the success of the thermal treatment, as well as the change of the mechanical properties.
Hertl
C
C
Lehrstuhl für Werkstoffkunde und Werkstoffmechanik, Technische Universität München, Boltzmannstrasse 15, 85748 Garching, Germany. hertl@wkm.mw.tum.de
Werner
E
E
Thull
R
R
Gbureck
U
U
D020099:Coated Materials, Biocompatible; D004058:Diffusion; D006244:Hardness; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
D020099:Coated Materials, Biocompatible; C009495:titanium dioxide; C041500:titanium nitride; D014025:Titanium; D010100:Oxygen