Development of electrically conductive zirconia Part1: The optimal process parameters and mechanical properties

The Taguchi method was applied to analyze the optimum process parameters of a 3 mol% yttria-tetragonal zirconia polycrystal (3Y-TZP) containing 30 wt% titanium nitride (TiN) (3Y-TZP/TiN). Four process parameters—(1) sintering type, (2) crushing time of TiN powder, (3) the first-step sintering duration, and (4) the second-step sintering temperature were chosen as the controlling factors. Fracture toughness, flexural strength, hardness, relative density, and electric resistance were examined using an L9 orthogonal array. The results indicated that the fracture toughness was mainly affected by the duration of the first sintering step. The highest fracture toughness (9.275 MPa m1/2) was achieved at 97.3 vol% of the tetragonal phase in 3Y-TZP/TiN. In addition, 3Y-TZP/TiN possessing a high fracture toughness of 8.59 MPa m1/2 and a flexural strength of 680.77 MPa was fabricated using the optimum process parameters, 8 h crushing time of TiN powder, and the two-step sintering process. The electric resistance for 3Y-TZP/TiN was 3.26×10−3 Ω cm.