Bastow T J, Smith M E
CSIRO Division of Materials Science and Technology, Clayton, Victoria, Australia.
Solid State Nucl Magn Reson. 1992 Nov;1(4):165-74. doi: 10.1016/s0926-2040(10)80001-3.
A detailed 91Zr NMR investigation is presented of the five component (cubic, monoclinic, tetragonal, orthorhombic and delta) phase mixture in the transformation toughened engineering ceramic, magnesia-partially-stabilised zirconia (MgPSZ). The phases are distinguished on the basis of the quadrupole interaction displayed in the powder pattern of the 91Zr(1/2, -1/2) transition. This paper reports: (i) the first characterisation of the magnesia-fully-stabilised cubic phase at the eutectic composition (13.5 mol% MgO); (ii) the observation of a poorly ordered tetragonal phase on fast cooling ZrO2 (9.3 mol% MgO) from the cubic phase field at 1720 degrees C, and the subsequent growth and ordering of the tetragonal phase precipitates due to further annealing; (iii) the observation of the (partial) transformation of the cubic phase to the ordered delta-phase (Mg2Zr5O12) on annealing MgPSZ at 1100 degrees C for 8 h; and (iv) the observation of the transformation of the tetragonal phase into the orthorhombic phase after cooling in liquid nitrogen, and the reverse transformation after heating to 600 degrees C.
本文对相变增韧工程陶瓷——氧化镁部分稳定氧化锆（MgPSZ）中的五相混合物（立方相、单斜相、四方相、正交相和δ相）进行了详细的91Zr核磁共振研究。这些相是根据91Zr(1/2, -1/2)跃迁粉末图谱中显示的四极相互作用来区分的。本文报道了：（i）首次对共晶成分（13.5 mol% MgO）下的氧化镁完全稳定立方相进行表征；（ii）观察到在1720℃从立方相区快速冷却ZrO2（9.3 mol% MgO）时出现的无序四方相，以及随后由于进一步退火导致四方相沉淀的生长和有序化；（iii）观察到在1100℃对MgPSZ退火8小时后，立方相（部分）转变为有序δ相（Mg2Zr5O12）；（iv）观察到在液氮中冷却后四方相转变为正交相，以及加热到600℃后发生的逆转变。
