The high strength and hardness and the high temperature stability of spinel MgAl2O4 are among the properties that makes it an excellent candidate for advanced electromagnetic windows. The main requirement for this application is a high transparency. Due to its cubic structure, spinel can be produced in a transparent form. However since today spinel has not been extensively commercialized because of the difficulties encountered in the production process. Advancements in the comprehension of the experimental features affecting the transparency of spinel are presented. Transparent MgAl2O4 has been produced by hot pressing of a stoichiometric mixture of Al2O3 and MgO powders. Powders with a high purity level and with a high specific surface area have been selected and homogenously mixed by wet ball milling. LiF has been used as sintering additive. The influence of different hot pressing sintering cycles on the optical properties of spinel was studied. Various sintering cycles have been tested. The relationship among the processing conditions (sintering cycle), microstructure and transparency has been studied.
Production and characterization of transparent MgAl2O4 prepared by hot pressing
Laura Esposito;Andreana Piancastelli;
2012
Abstract
The high strength and hardness and the high temperature stability of spinel MgAl2O4 are among the properties that makes it an excellent candidate for advanced electromagnetic windows. The main requirement for this application is a high transparency. Due to its cubic structure, spinel can be produced in a transparent form. However since today spinel has not been extensively commercialized because of the difficulties encountered in the production process. Advancements in the comprehension of the experimental features affecting the transparency of spinel are presented. Transparent MgAl2O4 has been produced by hot pressing of a stoichiometric mixture of Al2O3 and MgO powders. Powders with a high purity level and with a high specific surface area have been selected and homogenously mixed by wet ball milling. LiF has been used as sintering additive. The influence of different hot pressing sintering cycles on the optical properties of spinel was studied. Various sintering cycles have been tested. The relationship among the processing conditions (sintering cycle), microstructure and transparency has been studied.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
