The Effect of Thermal Oxidation on the Photothermal Conversion Property of Tantalum Coatings

In this study, tantalum coatings are deposited by a plasma spraying method aiming at enhancing the biocompatibility of the titanium implant. Tantalum oxide coatings are gained through the thermal oxidation of tantalum coatings at different temperatures for photothermal therapy. The effect of thermal oxidation on the morphology, composition, and structure of tantalum coatings has been studied. The UV-VIS-NIR spectra results, cancer therapy effect in vitro, and photothermal conversion properties among the tantalum oxide coatings under varied thermal treatment conditions are compared comprehensively. It has been proven that the tantalum coating treated at 200 °C exhibits the most intense NIR adsorption, the highest photothermal conversion effect, and the most excellent photothermal ablation effect in vitro. The results reveal that incomplete oxidation at a low temperature leads to the formation of oxygen vacancies, which narrow the band gap; this promotes its photothermal conversion ability.