Preparation and properties of crystallizable Glass/Al2O3 composites for LTCC material

Abstract

The investigated low temperature Co fi red ceramics(LTCC) composite of 60wt% CaO-Al 2 O 3 -B 2 O 3 -SiO 2 glass and 40wt% α-Al 2 O 3 as a filler is a non-reactive system, which is a critical part of the low temperature Co fi red ceramics process. Through a study on densifi cation process, the phase transformation and microstructure can be revealed. Its composites typically consist of CaO-Al 2 O 3 -B 2 O 3 -SiO 2 glass and α-Al 2 O 3 powders of average particle size (D 50 =3.49 m). The sintering behavior, phase evaluation, sintered morphology, and microwave dielectric properties were investigated. In the fire range of 800 to 900 ℃, the composites were crystallized after completion of densifi cation. It is found that the composites start to densify at 825 ℃, simultaneously, the dielectric constant (ε r ) reaches its maximum. With increasing heat-treatment temperatures, due to the loose microstructure of the material, tanδ increases slightly. The last of the sintered samples were identifi ed as partly Anorthite at 850 ℃. At that temperature it has ε r of 7.9 and tanδ less than 1×10 3 , and can be used as a promising LTCC material.