Mechanical properties and bioactive surface modification via alkali-heat treatment of porous titanium for biomedical applications

Porous titanium with relative density from 0.4 to 0.64 was prepared by powder metallurgy. The porous structures were examined by scanning electron microscopy and phase constituents were analysed by X-ray diffraction. Mechanical properties of the porous titanium were investigated using a compressive test. To enhance the bioactivity of the alloy surface, alkali-heat treatment was used to modify the surface. Results indicate that the elastic modulus and plateau stress of the porous titanium samples both as-sintered and alkali and heat treatment decrease with decreasing relative density. And the relationship between relative yield stress and elastic modulus with relative density of porous titanium after alkali and heat treatment are agreement with that of as-sintered porous titanium. After alkali-heat treatment, a bioactive Na₂Ti₅O₁₁ layer formed on the surface of the pre-treated porous titanium. A reduction in the number and severity of this bioactive deposition was observed with the decrease in relative density of porous titanium because of the increasing surface area. In a word, The mechanical properties of the porous titanium can be tailored to match those of human bone, therefore, these bioactive porous titanium have the potential to be a bioactive implant material.