The effects of B2O3 addition, as a sintering agent, on the sintering behavior, microstructure and dielectric properties of CaMgSi2O6 ceramic have been investigated. The CaO-MgO-B2O3-SiO2 glassy phase came forth by add...The effects of B2O3 addition, as a sintering agent, on the sintering behavior, microstructure and dielectric properties of CaMgSi2O6 ceramic have been investigated. The CaO-MgO-B2O3-SiO2 glassy phase came forth by adding B2O3 into CaO-MgO-SiO2 ceramic powders, and it was advantageous to lower the synthesis temperature of CaMgSi2O6 crystalline phase. Moreover, the emergence of CaO-MgO-B2O3-SiO2 glass phase could effectively lower the sintering temperature of CaMgSi2O6 ceramic and promote the CaMgSi2O6 grains growing. With 6 wt pct B2O3 addition, the densification temperature of CaMgSi2O6 ceramic could be effectively reduced from 1300 to 1100℃, and the dielectric constant （εr） and dielectric loss （tanδ） were： εr=7.61 and tanδ=7.4×10^-4 （1 MHz）.展开更多
采用光学显微镜、扫描和透射电子显微镜研究了含Ca、Si镁合金的显微组织特征。铸态下,仅含Ca的镁合金主要由镁基体和晶界离异共晶组织(Mg+Mg2Ca)组成;加入约0.5%(质量分数)Si后,晶界离异共晶组织消失,在晶界附近及晶内形成弥散分布的细...采用光学显微镜、扫描和透射电子显微镜研究了含Ca、Si镁合金的显微组织特征。铸态下,仅含Ca的镁合金主要由镁基体和晶界离异共晶组织(Mg+Mg2Ca)组成;加入约0.5%(质量分数)Si后,晶界离异共晶组织消失,在晶界附近及晶内形成弥散分布的细小点状(球状)、针状和粗块状CaMgSi相;当含Si量较高(约1.0%)时,出现中国字形(针状)的Mg2Si相。固溶时效后,只含Ca的镁合金中晶界处离异共晶组织消失,代之以长大了的颗粒状Mg2Ca相;而Mg Ca Si合金的固溶时效组织较铸态无明显变化。对合金常温和高温短时拉伸性能也作了初步探讨。展开更多
基金supported by the Program for New Century Excellent Talents in University (No. NCET-07-0786)the Nature Science Foundation of Zhejiang Province (No. R406007)the Science Technology of Zhejiang Province (No. 2008C21054)
文摘The effects of B2O3 addition, as a sintering agent, on the sintering behavior, microstructure and dielectric properties of CaMgSi2O6 ceramic have been investigated. The CaO-MgO-B2O3-SiO2 glassy phase came forth by adding B2O3 into CaO-MgO-SiO2 ceramic powders, and it was advantageous to lower the synthesis temperature of CaMgSi2O6 crystalline phase. Moreover, the emergence of CaO-MgO-B2O3-SiO2 glass phase could effectively lower the sintering temperature of CaMgSi2O6 ceramic and promote the CaMgSi2O6 grains growing. With 6 wt pct B2O3 addition, the densification temperature of CaMgSi2O6 ceramic could be effectively reduced from 1300 to 1100℃, and the dielectric constant （εr） and dielectric loss （tanδ） were： εr=7.61 and tanδ=7.4×10^-4 （1 MHz）.
文摘采用光学显微镜、扫描和透射电子显微镜研究了含Ca、Si镁合金的显微组织特征。铸态下,仅含Ca的镁合金主要由镁基体和晶界离异共晶组织(Mg+Mg2Ca)组成;加入约0.5%(质量分数)Si后,晶界离异共晶组织消失,在晶界附近及晶内形成弥散分布的细小点状(球状)、针状和粗块状CaMgSi相;当含Si量较高(约1.0%)时,出现中国字形(针状)的Mg2Si相。固溶时效后,只含Ca的镁合金中晶界处离异共晶组织消失,代之以长大了的颗粒状Mg2Ca相;而Mg Ca Si合金的固溶时效组织较铸态无明显变化。对合金常温和高温短时拉伸性能也作了初步探讨。
