Alumina-based ceramics for core materials

摘要

Alumina-based ceramics for core materials having a good leachability and being non reactive with the alloy up to 1800°C.;The ceramic material, before firing, consists of at least an alumina-based compound material having the general formula MO NAl₂O_3, wherein M is Na_2, Ca, Sr or Ba, N is from 9 to 11 when M is Na₂ and N is 6 when M is Ca, Sr or Ba. and is. after firing, being characterized by a density of from 40 percent to 75 percent of theoretical and an interconnected network defining a plurality of interstices in which undoped alumina grains are found.;Application for making cores for casting directionally solidified eutectic and superalloy materials.