Translucent γ-AlOOH and γ-Al2O3 glass-ceramics using the cold sintering process

Cold Sintering Process has been applied to hydroxide precursors Al(OH)(3), xH(2)O to promote in situ reactive sintering. The application of sintering temperatures < 400 degrees C led to the release of OH groups and partial crystallization into boehmite gamma-AlOOH. This latter step is accompanied by a densification stage leading to the production of dense translucent pellet. From skeletal density measurements, it appears that not all the pellet is composed of crystalline phase, but contains a mix of amorphous and crystalline phase. The presence of amorphous phase seems to favor the mechanical stability of the samples made of the intermediate boehmite phase, which is brittle due to its oriented layer structure. Further heat treatment in an oven at 500 degrees C induces the transformation of boehmite into gamma-Al2O3. Here we demonstrate the possibility to produce optically translucent ceramics of low temperature stability gamma alumina structure. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All right sreserved.

Automated summary

The Cold Sintering Process was used to promote in situ reactive sintering of hydroxide precursors Al(OH)3, xH2O. The result was dense translucent pellets containing a mix of amorphous and crystalline phases. Further heat treatment induced the transformation of boehmite into gamma-Al2O3, demonstrating the possibility of producing optically translucent ceramics with low temperature stability.