The Anatase Formation on Anodised Titanium in Sulphuric Acid

Anodic oxidation is used to evaluate the effects of pure titanium in a sulphuric acid electrolyte in order to evaluate the relationship between the Ti02 anatase crystalline phase formation and anodization parameters. Multiple characterisation techniques were used and found that the thickness showed significant increase in TiOz at 70V, FESEM observed significant porosity at the arcing voltage commencement (1 OOV). XRD analysis observed observed anatase peak ,threshold at 70V, However Rarnan Microscopy showed anatase significance formation between 20V-30V. We conclude that anatase presents at low voltage 20-30V while rutile peaks increase initially (100V and 150V) and the amount and /or crystallinity of anatase arelis influenced by the applied voltage. Introduction Anodic oxidation is used to modify the surfaces and properties of titanium (Ti) and aluminium owing to the resultant mechanical properties, corrosion resistance, non-biotoxicity, and biocompatibility [I]. Ti always is coated by an oxide surface layer of 1.5-10 nrn thickness, which forms spontaneously upon exposure to air and atmospheric water vapour [2]. Anodic oxidation of Ti allows the controlled production of a protective oxide surface layer much thicker than that formed rutile, present several peculiar features, such as photocatalytic behaviour, super-hydrophilicity and biocompatible properties [4]. The electrolytes most commonly used to anodise Ti are sulphuric and phosphoric acids [5]. This work focuses on the evaluation of the effects of titanium anodic oxidation in a sulphuric acid electrolyte on the formation of TiOz crystal phases in the oxide layer; the impact of process parameters modification will be studied, in order to maximize the achievement of these structures, especially for what concerns the anatase form. In particular, the relationship between anatase formation and process parameters will be evidenced [4]. Experimental method Sample Preparation High-purity Ti foils of dimensions 25 mm x 10 mm x 0.5 mm were wet hand-polished using 1200 grit (-1 pm) abrasive paper, followed by immersion in an ultrasonic bath with acetone, rinsing with distilled water, and drying with compressed air. Anodic oxidation was done in an electrochemical cell containing -0.4 L aqueous solutions of H2SO4 (%) [I]. The anode and cathode were Ti foil and the anodising was done with a programmable power supply. The associated experimental parameters are shown in Table 1. Table 1 : Parameters Used for Anodic Oxidation naturally. These coatings may be dense or of porous, amorphous or crystalline, depending on the conditions, such as electrolyte type, solution concentration, and applied potential [3]. Crystalline oxides, that is, anatase and Parameters