Passive film characteristics of laser powder bed fusion produced commercially pure titanium: effects of temperature and annealing on corrosion resistance
Wenna Zhang, Liang‐Yu Chen, Ayisen Saimi, Lijuan Huang, Junjie He, Xiaoping Luo
Abstract
Laser powder bed fusion (L-PBF) produced commercial pure titanium (CP–Ti), which has great potential in oral healthcare. However, the effect of high-temperature environments (e.g., oral temperatures up to 60 °C during hot food intake) on its corrosion resistance remains unclear. Therefore, this work investigated the corrosion behavior and passive film characteristics of as-built and annealed CP-Ti in artificial saliva at 37 °C and 60 °C. As-built CP Ti consists dominated of α′ phase, while the annealed CP-Ti exhibits distinct grain boundaries with a mixture of α′ grains and sub-micron subgrains. Electrochemical tests conducted at 37 °C demonstrate that the annealed CP-Ti exhibits lower corrosion current density and higher film impedance than those of the as-built CP-Ti. Such a phenomenon is attributed to the lower diffusion coefficients and flux of oxygen vacancies in the passive film on the annealed CP-Ti. When the temperature rises to 60 °C, the annealed CP-Ti still shows better corrosion resistance than the as-built CP-Ti. The elevated temperature increases the migration of oxygen vacancies in the passive film, resulting in the enhanced growth and dissolution of the passive film on the samples. As investigated, the influence of temperature on the corrosion resistance of the samples obeys the Arrhenius equation.