Influence of Oxidative Etching Solution Temperatures on the Surface Roughness and Wettability of a Titanium Alloy

Recently, a simple surface modification treatment of titanium (Ti) was developed to produce nano-and micro-scale features on the surfaces via simple immersion in an oxidative aqueous solution (30% hydrogen peroxide/5% sodium bicarbonate). However, this treatment method of Ti surfaces requires a relatively long immersion time (4 h) in the oxidative solution. In this study, we investigated whether an increase in the temperature of the oxidative etching solution can shorten the immersion time of Ti effectively. Polished grade 5 dental Ti (Ti-6Al-4V) discs were immersed in the oxidative aqueous solution either for 30 or 60 min. The temperature of the etching solution was maintained at 25 (similar to room temperature), 35, or 45 °C during etching. The etched surfaces were studied in terms of micro- and nano-structures, surface roughness, and wettability (surface energy). The increase in the temperature of the solution accelerated the etching effect of Ti and created both micro- and nano-structures on the surfaces more effectively. In particular, immersion for 60 min at the solution temperature of 35 °C significantly increased the surface roughness and wettability, although the etching effect was enhanced further at the solution temperature of 45 °C.