Low‐Temperature Sintering and Microwave Dielectric Properties of Anorthite‐Based Glass‐Ceramics

Abstract

TiO2 nucleated anorthite‐based glass‐ceramics were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including apparent bulk density and water absorption, were examined to evaluate the sintering behavior of anorthite‐based glass‐ceramic. Results showed that the complete‐densification temperature for specimens was as low as 900°C. Sufficient crystallization was achieved by subsequently raising the firing temperature to 950°C, and the dielectric quality factor was promoted to the maximum value. Contents of nucleating agent (TiO2) played an important role in the dielectric constants. The crystallinity was controlled by raising the firing temperature at a constant heating rate. The degree of crystallization affected the dielectric properties of sintered glass‐ceramics. At the resonant frequency of 10 GHz, anorthite glass‐ceramics with 5 wt% TiO2 possessed the lowest permittivity of 8 and exhibited appropriate dielectric properties as compared with those with B2O3 and 10 wt% TiO2.

Effects of various oxide fillers on physical and dielectric properties of calcium aluminoborosilicate-based dielectrics

“…The temperature coefficient of resonance frequency (TCF) was measured in the temperature range of 25 to 70°C. The anorthite phase has been found to be a major phase as reported in the LTCC compositions composed of typical calcium aluminoborosilicate and Al 2 O 3 filler [14]. For the LTCC composition containing BaTiO 3 , the BaTiO 3 phase completely disappeared and the new BaAl 2 Si 2 O 8 phase was found to be predominant as a result of firing.…”

La2O3–B2O3–TiO2 Glass/BaO–Nd2O3–TiO2 ceramic for high quality factor low temperature co-fired ceramic dielectric

“…In order to mitigate the low quality factor in the microwave dielectric, low melting temperature glass has to be transformed into optimized crystallization having low dielectric loss during sintering process [9][10][11][12][13][14]. Previous research on glass-ceramics has led to the development of three leading methods of optimizing crystallization.…”

“…Low temperature co-fired ceramic (LTCC) technology provides a viable solution to these challenges [2][3][4][5][6][7][8][9]. LTCC materials for microwave applications require microwave dielectric properties, such as high dielectric constant (e r ), high quality factor (Q*f 0 ), and a small temperature coefficient of resonant frequency (t f ) [5][6][7][8][9][10].…”

Towards rational design of low-temperature co-fired ceramic (LTCC) materials

“…Some ions and clusters introduced into the base glass as the nucleation agent is representative of heterogeneous nucleation. For the glasses of silicate, aluminate, and borate, the most popular nucleation agent are TiO 2 and ZrO 2 [6,10,45], then some transition metal oxide, such as Fe 2 O 3 , Cr 2 O 3 , V 2 O 5 and NiO. However, the introduction of these compounds tends to increase the dielectric loss of the ceramics.…”