ZHOU Shijie (1997-), Master. E-mail: 775155570@qq.com
A series of Ca2+-doped cordierite ((Mg1-xCax)2Al4Si5O18) ceramic powders were prepared by a sol-gel method. The effect of the substitution of Ca2+ for Mg2+ of cordierite ceramics on the sintering properties, structural characteristics, microwave dielectric properties and fracture toughness was investigated. The results show that the introduction of Ca2+ can improve the sintering activity of the powder, thus improving the density of the sample and the sintering densification. The single α-cordierite phase is obtained in the range of 0<x≤0.1 because Ca2+ is doped into the cordierite structure to form the solid solution. When the x value is larger than 0.1, an anorthite phase appears. The dielectric constant of cordierite ceramic decreases, and the quality factor, the temperature coefficient of frequency and fracture toughness improve when Mg2+ substitutes for Ca2+. The optimum performance of (Mg1-xCax)2Al4Si5O18 ceramic is obtained when the x value is 0.1, i.e., the dielectric constant of 4.61, the quality factor of 9949GHz and the temperature coefficient of frequency of -26×10-6/℃, and the fracture toughness of 4.76MPa·m1/2.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |