High temperature oxidation behavior of TiC ceramics by hot-pressed sintering

The long-term oxidation resistance of TiC ceramics is a key parameter for their application in aerospace industries and must be carefully evaluated at high temperatures and various airflow environments. TiC single-phase ceramics are prepared by hot-pressed sintering. The non-isothermal oxidation properties of TiC ceramics from room temperature to 1500 ℃ are analyzed by thermogravimetry-differential scanning calorimeter （TG-DSC） thermal analyzer. The isothermal oxidation properties of TiC ceramics in different environments （temperature： 1000，1200，1500 ℃， atmosphere： static air， one-way air flow， low oxygen partial pressure air flow） are analyzed by a tubular oxidation furnace， and its oxidation rate is characterized by monitoring the change in mass per unit area. The results show that the diffusion activation energy of TiC ceramics at 1200-1500 ℃ is about 378.78 kJ/mol， and the reaction activation energy is about 17.82 kJ/mol. TiC ceramics have a three-layer structure of TiO2 oxide layer， TiCxOy interlayer and TiC substrate after oxidation. The results of oxidation kinetics indicate that the oxidation rate is controlled by reaction rate at 1200 ℃， and is controlled by oxygen diffusion at 1500 ℃. At 1000 ℃， the oxidation rate in the initial stage （the first 100 min） is controlled by diffusion， then by reaction. In the low oxygen partial pressure air flow environment， the reaction rate and diffusion rate of high-temperature molecular oxygen oxidation of TiC ceramics are both inhibited， and a relatively dense TiO2 oxide layer can be formed.