Fabrication of MgAl2O4/Al2O3 laminated transparent composite by spark-plasma-sintering (SPS) processing

In order to improve the mechanical properties of polycrystalline transparent MgAl2O4 spinel, fine-grained Al2O3 layer was formed on the MgAl2O4 by simple one step spark-plasma-sintering (SPS) processing. By the sintering at a relatively lower temperature of 1225 degrees C under a pressure of 300 MPa, the fabricated MgAl(2)O4/Al2O3 laminated composites can attain transparency with an in-line transmission higher than 40% at a visible range of 0.5 mu m. In addition to the transparency, the laminated composite structure can attain a hardness of H-v = 29.1 GPa, which is much higher than 17.2 GPa of monolithic MgAl2O4 and 26.6 GPa of monolithic Al2O3. This result indicates that although the transparency need to be improved for applications, the laminated composite structure that can be obtained by the one step SPS processing would be effective for attaining the MgAl2O4 spinel polycrystals with good optical and mechanical properties simultaneously. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

By using a simple one step spark-plasma-sintering (SPS) process to form a fine-grained Al2O3 layer on MgAl2O4, transparent MgAl2O4/Al2O3 laminated composites with an in-line transmission higher than 40% and a hardness of 29.1 GPa can be obtained. This composite structure demonstrates better mechanical properties compared to traditional monolithic materials.