Influence of sintering temperature on the thermal conductivity of digital light processing 3D-printed yttria-stabilized zirconia ceramic

In this work, digital light processing (DLP) - common 3D-printed technology - was used to shape yttria-stabilized zirconia (YSZ) ceramic green bodies. Influences of sintering temperature on thermal conductivity of YSZ ceramics were studied systematically. Results showed that thermal conductivity of ceramics increased from 1.89 W/(m & BULL;K) to 2.99 W/(m & BULL;K) with increasing sintering temperature from 1200 degrees C to 1600 degrees C. Porosity of YSZ ceramics decreased from 15.00% to 1.59%, and grain size increased from 0.13 & PLUSMN;0.03 & mu;m to 0.70 & PLUSMN;0.20 & mu;m. At lower sintering temperature from 1200 degrees C to 1400 degrees C, excessive pores exerted an impact on thermal conductivity due to phonon scattering processes. With further increase in temperature to 1600 degrees C, the amount of grain boundaries controlled by grain size was main factor affecting thermal conductivity of ceramics. In particular, fewer grain boundaries reduced phonon scattering, resulting in the increase in thermal conductivity. Therefore, sintering temperature is key parameter influencing thermal conductivity of YSZ ceramics through porosity, grain size and grain boundary at different stages.