ZHANG Ling ¹, ZHOU Man ¹, DAI Baoxin ¹, HE Yu ¹, LIU Kaige ¹, XIANG Bingxi ¹, ZHAI Jianpang ¹, XIAO Zhuohao ², KONG Ling Bing ¹

(1. College of New Materials and New Energies, Shenzhen Technology University, Shenzhen 518118, Guangdong, China; 2. School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China)

Abstract: Matrix glass of Li₂O-Al₂O₃-SiO₂ (LAS) glass ceramics without zirconia was prepared by using melting method with Li₂CO₃, Al₂O₃, SiO₂ as the main materials. Then, ZrO₂/LAS glass-ceramic composites with different contents of ZrO₂ were fabricated by using high-energy ball milling, grinding and sintering. Thermal behaviors of the raw materials were examined, while the effects of ZrO₂ and sintering temperature on phase composition, macro/microscopic morphology, thermal expansion, bulk density and hardness of the composites were systematically studied. It is found that phase composition of the ZrO₂/LAS glass-ceramics composites is mainly dependent on sintering temperature, while the addition of ZrO₂ has a strong influence on denseness, thermal expansion and mechanical properties of the composites. The composites with high denseness were achieved as the sintering temperature is 1100 ℃ and the content of ZrO₂ is 30 wt.%, while the low linear shrinkage (3.55 × 10⁻⁵) was observed at 800 ℃. When the ZrO₂ content was 10–30 wt.%, the average CTEs of the composites at 30–300 ℃ were negative and close to zero, which showed the good thermal stability of the composites. The Vickers hardness of the composites increased linearly with the increase of ZrO₂ content, indicating that the addition of ZrO₂ is beneficial to improve the mechanical properties of the composites. The introduction of ZrO₂ into LAS glass could be used as an effective reference for the preparation of glass-ceramic composites with low thermal expansion coefficient and high mechanical properties.

Key words: LAS glass ceramics; ZrO₂; sintering method; low thermal expansion coefficient; hardness