Papers by Author: Han Feng Wang

Abstract: The cordierite powders have been synthesized by low temperature combustion technique using urea as fuel, nitrates as oxidizer and silicic acid as silica source. The sintering behavior and crystallization process were investigated. The results showed that the powders could be sintered at a temperature lower than 1000 °C. The μ-cordierite crystallized from glass at first, and then transformed into α-cordierite at higher temperature. The obtained cordierite based glass ceramics at different temperatures have low dielectric constant (4.16 ~ 5.02 at 1 MHz) and low dielectric dissipation factor (≈ 0.003 at 1 MHz) as well as low temperature sintering behavior, which is compatible for electronic packaging.

Abstract: The effects of Li+ addition on the sintering and microstructural evolution of cordierite were analyzed. As nucleating agent, the Li+ additive decreased the expansion coefficient and dielectric constant. The doping of Li+ was found to block the phase transition from μ-cordierite to α-cordierite and increase sintering temperatures. The effect of Li+ on the activation of cordierite can be attributed to the nucleation of cordierite. Too much Li+ will inhibit the cordierite crystallization and encourage amblygonite crystallization. Cordierite powders were prepared by sol-gel processing.

Abstract: The effects of Bi3+ addition on the sintering performance and microstructural evolution of cordierite were analyzed in this paper. Cordierite powders were prepared by sol-gel processing. As nucleating agent, the Bi3+ additive was found to promote the phase transition from µ-cordierite to α-cordierite and decrease sintering temperatures. The effect of Bi3+ on the activation of cordierite can be attributed to the nucleation of cordierite. The doping of Bi3+ increased the expansion coefficient and dielectric constant. Too much Bi3+ will inhibit the cordierite crystallization and encourage anorthite crystallization.