“…In such systems, some mixtures of silica-based glass and crystalline Al 2 O 3 have been studied as a substrate material for LTCC module because of their high flexural strength and superior chemical durability. [1][2][3] In the mixture of silica-based glass and Al 2 O 3 , feldspar (MAl 2 Si 2 O 8 ), is precipitated by the reaction, resulting in three phases, Al 2 O 3 , feldspar, and glass. 1,4,5 The amount of glass and Al 2 O 3 phases is reduced and the amount of feldspar phase is increased during sintering process.…”