The effect of aluminum sources on synthesis of low expansion glass–ceramics in lithia–alumina–silica system by sol–gel route

Abstract This paper investigated the effect of different aluminum sources on the crystallization behaviors, thermal expansion and morphology of lithium aluminosilicate glass–ceramics sintered at different temperatures. Specimens were prepared by sol–gel technology. The crystalline phase in the specimen with Al(NO 3 ) 3 ⋅9H 2 O aluminum source sintered at 1300 °C has shown a major phase of Li 2 Al 2 Si 3 O 10 accompanied by minor phase of LiAl 5 O 8 and trace amount of SiO 2 . The β-eucryptite appeared as the only phase in the specimens with aluminum isopropoxide or aluminum isopropoxide mixed with Al(NO 3 ) 3 ⋅9H 2 O aluminum sources sintered at 1300 °C. The sintering temperature has significant effect on the thermal expansion behavior of all the specimens. SEM indicated that microstructures were spherulitic crystals and no distinct differences were observed in the specimens with different aluminum sources.