Gradient Ti/HAp composite biomaterials fabricated by controlled thermodynamic powder metallurgy.

The reliability of hard tissue engineering processes is crucial in a variety of application such as knee or hip joint replacement. For a successful integration of any implant, bone regeneration, osseointegration at the interface bone and implant as well as mitigating inflammatory events are essential aspects.

The objective of this work is to extend the biocompatibility, osteoconductivity and mechanical performance associated with a lifetime of biomaterials based on Titanium (Ti). The hypothesis state that the bioactivity of titanium alloy biomaterials can be increased by the addition of hydroxyapatite (HAp) and further boosted by porosity. Designing the gradient bio composite starting with preparation of materials mixture of Ti6Al4V powder, synthetized HAp powder (5 and 10% wt.) and a foaming agent cabroxymethylocelulose (CMC) (5 and 10% wt.) milled to a very uniform density by ZrO₂ ball miller. In a step next the powders mixtures were cascaded in a press die the first layer was Ti6Al4V+5%HAp+5%CMC and upper layer was Ti6Al4V+10%HAp+10%CMC, and next pressed by the cold isostatic pressing (CIP). Sintering of the composites was performed on a Yttria-stabilized zirconia plate with air channels in a vacuum furnace at 1300°C under Ar protective atmosphere. The results show high potential of this methodology for preparation of gradient structure, with lower layer hardness reaching 10GPa and elastic modulus 154 GPa and upper layer containing HAP and porosity reaching 10%.

The authors gratefully acknowledge financial support of the project “New Generation of Bioactive Laser Textured Ti/Hap Implants” under acronym “BiLaTex” carried out within M-ERA.NET 3 Call 2022 programme in the National Centre for Research and Development (ERA.NET3/2022/48/BiLaTex/2023).