TiO2 coatings on titanium obtained by anodising in a 2% Na2SiO3 solution at various voltages

Abstract

Commercially pure titanium is recognised as one of the most biocompatible materials used in everyday medicine, particularly in prosthodontics. However, its high reactivity with oxygen and low thermal expansion makes titanium difficult to process, making it less popular as a material for porcelain fused to metal substructures. Analysing the available literature studies, both positive and negative effects of the oxide layer on the titanium-ceramic bond have been found. The given work attempted to anodically create oxide coatings in a 2% Na2SiO3 solution on commercially pure titanium, which could serve as substructures for crowns and dental bridges.Grade 2 titanium discs (diameter 20 mm, height 5 mm) were ground and polished. The alloy composition was determined by X-ray fluorescence analysis. The samples were divided into six groups and subjected to anodic oxidation in a 2% Na2SiO3 solution at constant voltages: 230 V, 270 V, 300 V, 350 V, 400 V, and a time of t = 1 min. The obtained oxide layers were examined by X-ray diffraction, chemical composition analysis, and SEM observation.Coating thicknesses ranging from 0.65 μm to 13.2 μm were obtained. Besides titanium oxide, an amorphous phase is present in the anodised layer.It is crucial to provide the ideal voltage directly related to the employed solution to maintain the useable thickness of the oxide layers. Variations in oxide layer thickness beyond optimal value may lead to exfoliating if it exceeds 1 μm or present fractures if it subceeds 1 μm.Titanium oxide layers obtained by anodic oxidation are mainly tested on their biocompatibility and tissue integration so important in implantology. However, the given paper focuses on creating oxide layers that may strengthen the bond between titanium and dental ceramics.