Structural Properties Of Yttria Stabilized Zirconia With Different Nano Alumina - Magnesia Spinel Additions

Abstract

Micro Y2O3 powder (8 wt%) was added to zirconia to prepare Y-PZT, while the mixture of nano (MgO-Al2O3) magnesium aluminate spinel (MAS) was prepared by mixing 28.33 wt% of nano-MgO with 71.67 wt% of nano-Al2O3 powders. The MAS was added to the Y-PSZ by different weight percentage (5, 10, 15, 20 and 25 wt%), and after homogeneous mixing the specimens was formed by axial pressing and sintered at1550 °C for four hours as soaking time. X-ray diffraction analysis shows that the three phases of zirconia (m: monoclinic, t: tetragonal and c: cubic) have emerged as a result of the addition of MgO with the formation of MAS. Increasing the percentages additions of MAS was leaded to increase the crystal size from 34 to 48 nm, while the lattice strain was decreased from 0.4 % to 0.3 %. As well as, the grain size was calculated for surface of specimens and it was found to be decreasing from the micro-size (> 0.6 μm) to nano-size (∼ 108 nm) with a clear decrease in surface roughness from 6.5 nm to 1 nm due to the nano-MAS additions.