Improving the comprehensive properties of ZrO2–C materials with aid of TiO2 addition

Owing to the harsh working condition, the ZrO2–C materials used in the slag line in the submerged entry nozzle are confronted with serious slag erosion. In order to solve this issue, different amounts of TiO2 addition ranging from 0 to 6 wt% are added and their effects on the erosion resistance of ZrO2–C materials in addition to phase composition, microstructure, physical properties and high-temperature mechanical properties are investigated in this work. When the sintering temperature is above 1400 °C, fine TiC grains and SiC whiskers are in-situ formed and distributed around ZrO2 particles, which can reinforce the matrix and improve the strength of ZrO2–C materials. With the amount of TiO2 addition increasing, the cold strength of ZrO2–C materials increases while the high-temperature strength slightly decreases. Combining with the erosion resistance, the optimum amount of TiO2 in ZrO2–C materials is determined to be 4 wt%, in which the cold compressive strength (46.13 MPa), the cold modulus of rupture (35.12 MPa) and the residual strength after thermal shock (15.01 MPa) reach the maximum. Based on this, the promotion mechanism of erosion resistance is further discussed with aid of molecular dynamics simulation.