Friction reduction using Nanothin Titanium layers on anodized aluminum as potential bioceramic material

While widespread industrially, anodized aluminum also finds bioengineering applications due to the abundance of nanopores and bioceramic nature of Al2O3. In this study, nanothin layers of TiO2 were deposited on 1050 and 6082 alloys to evaluate biocompatibility and friction. Periodontal ligament stromal (PDLS) cells showed higher adhesion on anodized 1050 alloy after 120 h incubation. Layers of Ti or TiO2 were formed on nanoporous anodized surfaces using magnetron sputtering or Atomic Layer Deposition (ALD), respectively. PDLS cell adhesion improved on nearly all sputtered specimens, meanwhile, ALD-deposited TiO2 layers were beneficial only to 6082 alloy. Both deposition methods highly improved the resistance to incidental friction for nanothin layers of 10-75 nm thickness. Counterintuitively, the tribological performance was much poorer both on thinner and thicker layers, such as 2.3 mu m Ti layer or titanium alloy BT1. Improvements in biocompatibility, friction reduction and other mechanical properties provide new opportunities for anodized aluminum with nanothin Ti layers as an innovative bioceramic material, in particular, due to its light weight and easy machinability.