Al2O3-3YSZ 복합체의 미세구조 및 기계적 특성에 대한 Al2O3 분말 크기의 영향

Abstract

3YSZ + (x) <TEX>$Al_2O_3$</TEX> composites (x = 20, 40, 60, 80 wt%) were fabricated and the influences of particle sizes of <TEX>$Al_2O_3$</TEX> on their microstructures and mechanical properties were investigated with XRD, SEM, vickers hardness and fracture toughness. <TEX>$Al_2O_3$</TEX>-3YSZ composites containing <TEX>$Al_2O_3$</TEX> powder of a <TEX>$0.3{\mu}m$</TEX> and an <TEX>$1.0{\mu}m$</TEX>, which are here in after named as <TEX>$Al_2O_3$</TEX>(<TEX>$0.3{\mu}m$</TEX>)-3YSZ and <TEX>$Al_2O_3$</TEX>(<TEX>$1.0{\mu}m$</TEX>)-3YSZ, respectively, were made by mixing raw materials, uni-axial pressing and sintering at <TEX>$1,400^{\circ}C$</TEX>, <TEX>$1,500^{\circ}C$</TEX>, and <TEX>$1,600^{\circ}C$</TEX>. <TEX>$Al_2O_3$</TEX>(<TEX>$0.3{\mu}m$</TEX>)-3YSZ composites show the higher density and the better mechanical properties than <TEX>$Al_2O_3$</TEX>(<TEX>$1.0{\mu}m$</TEX>)-3YSZ composites. The Vickers hardness of the <TEX>$Al_2O_3$</TEX>(<TEX>$0.3{\mu}m$</TEX>)-3YSZ composites show a peak value of 1,997 Hv at the content of 60 wt% <TEX>$Al_2O_3$</TEX>, which is a slightly higher value in comparison with 1,938 Hv of the <TEX>$Al_2O_3$</TEX>(<TEX>$1.0{\mu}m$</TEX>)-3YSZ composite. However, the fracture toughness of <TEX>$Al_2O_3$</TEX>-3YSZ composites monotonically increases with decreasing the content of <TEX>$Al_2O_3$</TEX> without any peak values. <TEX>$Al_2O_3$</TEX>(<TEX>$0.3{\mu}m$</TEX>)-3YSZ and <TEX>$Al_2O_3$</TEX>(<TEX>$1.0{\mu}m$</TEX>)-3YSZ composites sintered at <TEX>$1,600^{\circ}C$</TEX> have a maximum value of a <TEX>$6.9MPa{\cdot}m^{1/2}$</TEX> and a <TEX>$6.2MPa{\cdot}m^{1/2}$</TEX>, respectively at the composition of containing 20 wt% <TEX>$Al_2O_3$</TEX>. It should be noticed that the mechanical properties and the sintering density of the <TEX>$Al_2O_3$</TEX>-3YSZ composites can be enhanced by using more fine <TEX>$Al_2O_3$</TEX> powder due to their denser microstructure and smaller grain size.