Densification and Sintering Viscosity of Low‐Temperature Co‐Fired Ceramics

Abstract

In this paper, we present sintering and uniaxial viscosity data of three commercial low-temperature co-sintered ceramic systems, i.e., DuPont 951Tape (DU), Heraeus CT2000 (CT), and Ferro A6M (FE), measured by cyclic loading dilatometry. The viscosity initially decreases with temperature, changes little during the intermediate stage, and increases towards the end of densification. The viscosity increases sharply beyond the onset of crystallization. At slower heating rates, the viscosity increases at lower temperature, because of densification and crystallization. The isothermal viscosity data range from 0.1 to 100 GPa . s between 73% and 95% density. Ceramic particle-filled glasses show a higher isothermal viscosity compared with pure glass system, i.e., FE. From master viscosity curves based on isothermal data, the activation energies for viscous flow were B375730 and 450710 kJ/mol for DU and FE, respectively. These energies are comparable to values obtained from the master sintering curve approach.

Phase evolution and enhanced dielectric properties of BaO·Nd 2 O 3 ·TiO 2 ·B 2 O 3 glass-based dielectrics containing CaCu 3 Ti 4 O 12

“…The similar expansion was reported in our previous report where 60 wt% CCTO was combined with a different glass of calcium aluminoborosilicate glass [10]. Although the reason for the sudden expansion is unclear, our previous work has proposed that CCTO may be responsible for the expansion since CCTO is known to produce very rapid grain growth with accompanying exaggeratedly grown grains at relatively low temperatures of ∼1000 • C with a prolonged soaking time [12].…”

“…For example, the 30 wt% CCTO sample starts to densify at ∼609 • C while the 60 wt% CCTO sample at ∼618 • C. In addition, the 30 wt% CCTO sample led to a larger dimensional change (∼17.5%) with firing, while the 60 wt% CCTO samples showed a much smaller change of only ∼2%. It suggests that the relative content of glass plays an important role in progressing a sufficient level of densification at the LTCC target temperature of <900 • C. The densification of LTCC, with the considerable amount of glass, has been understood to come from the physical interaction of glass with filler [10,11]. Glass needs to wet sufficiently the surface of the filler particles and to form a network channel upon firing above its softening point [8].…”

Dielectric and microwave properties of ZrO2 doped CaO–SiO2–B2O3 ceramic matrix composites

“…CaO-SiO 2 -B 2 O 3 ceramic matrix composites possessing good dielectric and microwave properties have recently been widely investigated [1][2][3][4]. With crystalline wollastonite (␤-CaSiO 3 ) the major phase, CaO-SiO 2 -B 2 O 3 ceramic matrix composites are sintered at temperature of about 1000 • C [5,6].…”

Quantitative analysis of crystalline and remaining glass phases in CaO–B2O3–SiO2 ternary system glass ceramics

“…CaO-B 2 O 3 -SiO 2 ternary system glass ceramics have become an attractive material technology for electronic packaging applications due to their significant advantages, such as low sintering temperature, low dielectric constant, low cost and good compatibility with Si substrates [1][2][3][4][5]. From the material processing point of view, CaO-B 2 O 3 -SiO 2 ternary system is a glass ceramic composite, which can be densified at sintering temperatures <900 • C. It is known that the physical characteristics of the resulting glass ceramic composites, such as the dielectric constant, thermal expansion, and mechanical strength, are mainly determined by the amount of crystalline and glass phases.…”