α/β Phase Transformation in Porous Reaction-Bonded Silicon Nitride Ceramics
Porous reaction-bonded silicon nitride ceramics with different values of α/β ratio were obtained by setting the nitriding temperature and time. The influence of α/β phase transformation on the dielectric properties of porous silicon nitride ceramics has been investigated. The results show that the α/β transformation occurs when the nitriding temperature is higher than 1400°C . The values of α/β ratio decrease with increase of nitriding temperature and time. The dielectric constant ε′ and the dielectric loss tan δ of the samples increase because of the α/β transformation, and the change of the dielectric loss is more obvious. The increase of concentrations of point defects due to the α/β transformation leads to the significant increase of the dielectric loss.
Jianmin Zeng, Taosen Li, Shaojian Ma, Zhengyi Jiang and Daoguo Yang
J. Xu et al., "α/β Phase Transformation in Porous Reaction-Bonded Silicon Nitride Ceramics", Advanced Materials Research, Vols. 194-196, pp. 2225-2228, 2011