Fabrication of transparent ceramics through melt solidification of near eutectic compositions in HfO2–Al2O3–GdAlO3 system

Fabrication of bulk Al2O3 by combustion synthesis melt-casting under ultra-high gravity

“…Recent progress has demonstrated that when Al 2 O 3 is alloyed in eutectic proportions with other oxides, for instance, Re 2 O 3 (where Re stands for rare earth), the amorphous state of Al 2 O 3 could be obtained at cooling rate of less than 10 3 K/s [6]. Following such an idea, an Al 2 O 3 -based amorphous ball with the light transparency as high as 85% was developed at the cooling rate of 200-500 K/s [7,8].…”

Transparent Nano‐Composites Ceramics by Annealing of Amorphous Phase in the HfO2‐Al2O3‐GdAlO3 System

“…The cooling rate was estimated to be approximately 200‐500 K/s. The detailed procedure and equipment have been discussed in previous reports 26–29 …”

“…Those samples were polycrystalline, including ZrO 2 , and/or HfO 2 phases, thus not transparent at all. Just recently, we have succeeded in obtaining an amorphous phase in the HfO 2 ‐Al 2 O 3 ‐GdAlO 3 system, not by rapid quenching but by a simple melt solidification 26 . Here we will propose a new process to fabricate transparent nano‐composite ceramics by annealing the amorphous phase.…”

Fabrication of Crack‐Free C12A7 Nano‐Ceramics Composite from Eutectic Glass in the C12A7–CaYAlO4 System

“…Moreover, the amorphous phase (supercooled liquid) can be produced in the eutectic systems more easily than from the melt of a single phase and/or a stoichiometric compound. [15][16][17] Based on new findings on the eutectic solidification in the ternary Al 2 O 3 -Y 2 O 3 -ZrO 2 system 18-20 and amorphous formation in the Al 2 O 3 -Gd 2 O 3 -HfO 2 system, 15,21 we have studied the melt-solidification and amorphous phase formation in the system Al 2 O 3 -CaO-Y 2 O 3 . 22 In the present study, we demonstrate the fabrication of the C12A7 bulk materials with an arbitrary shape and size from the eutectic melts in the pseudobinary C12A7-CaYAlO 4 system, which should have more advantages to fabricate the C12A7 bulk materials than the composition of the stoichiometric C12A7.…”

“…The experimental procedures of the fabrication process by the arc imaging furnace is described in previous reports. 15,[18][19][20][21][22] After heating the sample at 8301C for 15 min in order to remove the residual stress, two parallel flat planes were prepared by mirror polishing on the sample globules in order to measure the precise linear expansion. The linear expansion behavior with crystallization of the glass samples were measured by loading 0.5 g weight, vertical to the mirror planes and at a heating rate of 101C/min from room temperature to 12001C using thermodilatometry (TD) (TD5000SA, Bruker AXS K.K., Tsukuba, Japan).…”