The subsolidus phase relations in the entire system Zr02-Y,03 were established using DTA, expansion measurements, and room-and high-temperature X-ray diffraction. Three eutectoid reactions were found in the system: ( a ) tetragonal zirconia solid solution-monoclinic zirconia solid solution + cubic zirconia solid solution at 4.5 mol% YZO3 and =490"C, ( b ) cubic zirconia solid solutiow Sphase Y4Zr3012+ hexagonalphase YsZrOlr at 45 mol% Y203 and -1325"+25"C, and (c) yttria C-type solid solutiowcubic zirconia solid solution+ hexagonal phase YcZrOll at =72mol% Yzo3 and 1650"k 50°C. W o ordered phases were also found in the system, one at 40 mol% Yzo3 with ideal formula Y4Zr3012, and another, a new hexagonal phase, at 75 mol% Yz03 with formula Y6ZrOI1. They decompose at 1375" and >175O"C into cubic zirconia solid solution and yttria C-type solid solution, respectively. The extent of the cubic zirconia and yttria C-type solid solution fields was also redetermined. By incorporating the known tetragonal-cubic zirconia transition temperature and the liquidus temperatures in the system, a new tentative phase diagramis given for the system ZrOZ-Yz03.

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In a community setting, 57% of all patients with GBM and only 32% of older patients received RT with concomitant and adjuvant temozolomide. In patients with surgical resection who were eligible for chemoradiation, initiation of RT ≤42 days was associated with better progression-free survival.

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Tetragonal zirconia doped with 3 mol% ErtOj was prepared by the gel-precipitation wet-chemical method. The compaction response of ultrafine (-8.5 nm), calcined, deagglomerated powders was studied. Initial sintering was studied using both isothermal and nonisothermal techniques, and an activation energy of 270 k 40 kJ/mol was obtained; therefore, grain-boundary diffusion was probably the predominant mechanism in the sintering stage. The microstructural development in the high-temperature-aged, sintered samples and its effect on density and mechanical properties were also studied. A theoretically dense body of tetragonal zirconia solid solution of 3 mol% Er2O3-ZrO2, obtained from sintering below 1400"C, was translucent. [

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