Preparation and characterization of microporous layers on titanium by anodization in sulfuric acid with and without hydrogen charging.

The formation of microporous oxide layers on titanium (Ti) by anodization in sulfuric acid (H2SO4) solution and the influence of prior hydrogen charging on their properties are examined using electrochemical techniques, scanning electron microscopy, grazing incident X-ray diffraction, and X-ray photoelectron spectroscopy. When Ti is anodized in 1 M aqueous H2SO4 solution at a high direct current (DC) potential (>150 V) for 1 min, a porous surface layer develops, and the process takes place with spark-discharge. Under these conditions, oxygen evolution at the Ti electrode proceeds vigorously and concurrently with the formation of anodic oxide.

Preparation and characterization of microporous layers on titanium.

Microporous layers on titanium (Ti) are formed by chemical treatment in highly concentrated alkaline media, and their properties and growth mechanism are examined using electrochemical techniques, in situ resistometry, scanning electron microscopy (SEM), grazing-incident X-ray diffraction (GIXRD), and glow discharge optical emission spectroscopy (GD-OES). Chemical treatment in a 5 M aqueous KOH solution yields results superior to those from the same treatment in a 5 M aqueous NaOH solution, while a 3 M aqueous LiOH solution does not produce porous layers. The cation constituting the solution plays a vital role in the process.