Fabrication of fine-grained alumina ceramics by a novel process integrating stereolithography and liquid precursor infiltration processing

Abstract In this study, we report a novel approach, integrating stereolithography and liquid precursor infiltration techniques, to fabricate fine-grained alumina ceramics. The XRD patterns of the sample immersed with Zr4+ or Zr4+ (Y3+) show that the sintered body contains Al2O3 and t-ZrO2 as the major phase and minor phase, respectively. Moreover, the t-ZrO2 phase in the sample immersed with Zr4+ (Y3+) shows intense peaks compared to the composite immersed with Zr4+. On the other hand, the sample immersed with Mg2+ contained Al2O3 and MgAl2O4 as the major phase and minor phase, respectively. The microstructure of the sample immersed with Zr4+ shows that ZrO2 particles are homogeneously distributed in the Al2O3 matrix, thus inhibiting the grain growth of alumina particles. Moreover, the sample immersed with Mg2+ shows a more dense and fine-grained structure. Compared to the non-infiltrated sample, the average grain size of the alumina sample immersed with Zr4+ or Mg2+ decreased. The sample infiltrated with Zr4+ (Y3+) had the smallest alumina average grain size of 1.14 µm. The ceramics prepared by infiltration showed a higher hardness (19.54 GPa), but a slightly lower fracture toughness (4.02 MPa m1/2) compared to the samples (17.2 GPa, 4.13 MPa m1/2) without infiltration.