Effects of P_2O_5 on sinterability, microstructures and properties of glass/alumina composites

摘要

We prepared the low-temperature fired glass/ alumina composites and investigated the influence of P_2O_5 on the sinterability, microstructure, dielectric property, and mechanical strength. The result showed that although the nucleating agent P_2O_5 can promote the crystallization of CaO-B_2O_3-SiO_2 (CBS) glass, excessive P_2O_5 have negative effects on the sintering behavior of composites. Because the density decreases gradually with increasing P_2O_5 addition, the dielectric and mechanical properties deteriorate dramatically. The densification mechanism via P_2O_5 modification is revealed further. Due to the crystallization effect of P_2O_5, the increase in viscosity impedes the flowability and wettability of liquid glass, which partly inhibits the liquid-phase sintering. 2 mol% P_2O_5-added CBS glass/alumina composite achieves densification at 900 ℃ (2.79 g/cm~3) and exhibits good performances: low dielectric constant (5.84), low dielectric loss (1.17 × 10~(-3)), and high flexural strength (166 MPa).