Effect of gadolinia–stabilized zirconia nanoparticles manufactured from Mist CVD on the mechanical properties of ceramics sintered by SPS

Zirconia is an engineering ceramic material with excellent comprehensive properties. However, it suffers from the inherent disadvantage of low fracture toughness. To improve its fracture toughness, Gd₂O₃ is an effective stabilizer. In the present study, Gd₂O₃–ZrO₂ composite powders were synthesized using the Mist CVD method. Following synthesis, these powders were pressed through spark plasma sintering. The crystallinity of the Gd₂O₃–ZrO₂ powders improved as the deposition temperature increased from 600°C to 900°C. The tetragonality (c/$\sqrt{2}$a) of the Gd–TZP composites increased from 0.99941 to 1.01571 as the Gd₂O₃ content increased from 2 mol% to 4 mol%, but it decreased when the content reached 5 mol%. The Gd₂O₃–ZrO₂ nanoparticles produced via the Mist CVD approach presented a unique hollow spherical structure. Under moist chemical vapor deposition (CVD) conditions with 4 mol% Gd₂O₃ at 1400°C, the Gd–TZP composites exhibited fracture toughness and hardness values of approximately 12.03 ± 0.15 MPa·m^1/2 and 12.16 ± 0.17 GPa, respectively.