[Determination of the tensile strength of superficial passive implant materials].
The crack strength of passivating surface materials or passive layers on electroconductive substrates is determined by the electronic detection of redox reactions at the electrolyte/sample interface. A sudden increase in corrosion current under mechanical tensile loading or bending moments indicates generation or propagation of macro- and micro-cracks in the passivating layer, and exposure of the substrate. A subsequent decrease in the current indicates repassivation. Titanium oxide passivating layers generated by oxygen diffusion hardening (ODH) on titanium show crack formation at a tensile load on the substrate of more than 230 MPa. Repassivating sandwich layers of tantalum and tantalum oxide on steel substrates (AISI 31 6L) generate micro-cracks at more than 300 MPa. The crack formation of the oxide surface materials correlates with the onset of plastic deformation of the substrate.
Macionczyk
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Thull
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D003343:Corrosion; D019544:Equipment Failure Analysis; D006801:Humans; D008422:Materials Testing; D010087:Oxides; D013499:Surface Properties; D013635:Tantalum; D013718:Tensile Strength; D014025:Titanium; D016474:Weight-Bearing
D010087:Oxides; C009495:titanium dioxide; D013635:Tantalum; D014025:Titanium; C078151:tantalum oxide