Effects of La 2 O 3 on Crystallization, Microstructure, and Properties of MgO‐Al 2 O 3 ‐SiO 2 ‐TiO 2 ‐La 2 O 3 Glass–ceramics

• Published in: International journal of applied glass science Vol. 7; no. 1; pp. 80 - 87
• Main Authors: Wang, Hui‐Juan, Li, Bo‐Tao, Lin, Hui‐Xing, Chen, Wei, Luo, Lan
• Format: Journal Article
• Language: English
• Published: 01.03.2016
• ISSN: 2041-1286; 2041-1294
• DOI: 10.1111/ijag.12119

A new glass–ceramic material with dielectric constant ε r ~10–11 and optimum quality factor Q  ×  f ~22,900 GH z was fabricated from 1MgO‐1.2Al 2 O 3 ‐2.8SiO 2 ‐1.2TiO 2 ‐ xL a 2 O 3 ( x  = 0.1, 0.2, 0.3, and 0.4) system, and the effects of La 2 O 3 on crystallization, microstructure, and dielectric properties of the material were investigated. The results show that the main crystalline phases in the glass–ceramics are lanthana‐based perrierite, rutile, and cordierite. As the content of La 2 O 3 increases, the formation of perrierite is promoted, while that for rutile and cordierite is suppressed. Meanwhile, a gradual homogenization in the microstructure has been observed. Specifically, the interconnected network, the formation of which is mainly due to the aggregation of perrierite, disintegrates with the increase of x from 0.1 to 0.3 and is hardly seen when x  = 0.4, finally resulting in a homogeneous microstructure with an overall uniform distribution of the phases and crystalline size. With higher content of La 2 O 3 , the dielectric constant of the material goes up slightly from 10 to 11, while the quality factor rises significantly from 12,500 GH z to 22,900 GH z. The variations of the dielectric properties are believed to be appreciably associated with the relative content of the phases present and the more homogeneous microstructure.