Abstract: BACKGROUND: 3% (molar percentage) yttria-stabilized tetragonal zirconia ceramics are prone to excessive wear of opposing teeth in practical applications, thereby increasing the risk of dentin exposure, causing toothache, pulp infection and other problems. Therefore, further improving the friction and wear properties of 3% yttria-stabilized tetragonal zirconia polycrystalline ceramics has become one of the hot topics in the current research of oral medical restorative materials.
OBJECTIVE: To explore the effect of barium titanate doping ratio on the microstructure, mechanical properties and friction and wear properties of 3% yttria-stabilized tetragonal zirconia ceramics.
METHODS: With 3% yttria-stabilized tetragonal zirconia ceramics as the main body, 3% yttria-stabilized tetragonal zirconia ceramic materials doped with barium titanate were prepared by high-temperature sintering method, in which the barium titanate doping amounts were 0%, 2%, 4%, and 6% of the ceramic powder mass, respectively. The lattice structure, mechanical properties, micromorphology and wear resistance of the four groups of materials were tested.
RESULTS AND CONCLUSION: (1) X-ray diffraction results showed that with the increase of barium titanate doping, the proportion of monoclinic zirconia and barium titanate in the composite ceramics continued to increase, while the proportion of tetragonal zirconia continued to decrease. (2) Scanning electron microscopy results showed that there were a large number of pores on the surface of pure 3% yttria-stabilized tetragonal zirconia ceramics, and the surface density was low; the number of pores on the surface of 4% and 6% barium titanate doped ceramics decreased and the surface density increased. (3) With the increase of barium titanate doping, the density of ceramics continued to decrease, and the pores first decreased and then increased. Among them, the density of 6% barium titanate doped ceramics was the lowest, and the porosity of 4% barium titanate doped ceramics was the lowest. With the increase of barium titanate doping, the Vickers hardness and fracture toughness of ceramics continued to decrease, and the elastic modulus first increased and then decreased. Among them, the elastic modulus of 4% barium titanate doped ceramics was the largest. (4) The scratch test was carried out using a diamond with a diameter of 10 µm. The results showed that with the increase of the amount of barium titanate doped, the friction coefficient and scratch depth of the ceramics first decreased and then increased. Among them, the friction coefficient and scratch depth of 4% barium titanate doped ceramics were the lowest. The results of scanning electron microscopy showed that the four groups of ceramic samples had different degrees of breakage on both sides of the scratch. Among them, the scratch edge of the pure yttria-stabilized tetragonal zirconia ceramic was the most serious, and the scratch edge of the 4% barium titanate-doped ceramic was the lightest. (5) The results show that the 4% barium titanate-doped yttria-stabilized tetragonal zirconia ceramic composite material has high wear resistance and strength, and can maintain long-term stability.

Key words: barium titanate, zirconium oxide, ceramics, oral medicine, wear resistance, micromorphology, engineered oral material