Glass alumina composites for functional and structural applications
Glass alumina composites for functional and structural applications
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用于功能和结构应用的玻璃氧化铝复合材料
DOI：
10.1016/j.ceramint.2019.03.194
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发表时间：
2019
影响因子：
5.2
通讯作者：
C. Duran
中科院分区：
文献类型：
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作者：
Gülsüm Meryem Dursun;C. Duran
将SiO_2-Al_2O_3-CaO基玻璃与Al_2O_3以不同的比例混合，制备了用于基片、低温共烧陶瓷和雷达罩等功能和结构应用的复合材料，这需要对其力学、热学和介电性能进行全面的表征。当玻璃质量分数为20和40 时，最佳致密化温度从1350 °C(20 重量%玻璃)降至1200 °C(40 重量%玻璃)；当玻璃质量分数为50~60 时，最佳致密化温度为850 °C(50~60 重量%玻璃)；当玻璃质量分数为50~60 时，最佳致密化温度为粘性烧结。主要物相为Al_2O_3以及825 °C后析出的钙长石。玻璃的加入降低了材料的力学性能，如杨氏模数从231 GPA(20 wt%玻璃)降至105 GPA(60 wt%玻璃)，弯曲强度从387 Mpa(20 wt%玻璃)和213 Mpa(60 wt%玻璃)降低。在5 频率下，玻璃质量分数为20-60 的复合材料的介电常数和介电损耗分别为8.76-7.32和0.0022-0.0081 MHz。热膨胀系数也随着玻璃含量的增加而降低，从7.72 ppm/°C(20 wt%玻璃)到6.66 ppm/°C(60 wt%玻璃)。含50-60 wt%玻璃的复合材料具有较低的致密化温度(<；950 °C)、较低的介电性能以及优化的机械和热性能，适用于基片和低温共烧陶瓷应用。用流延法制备了含55 %(质量分数)玻璃的复合材料，并与银电极共烧，没有任何额外的相形成和形状变形。此外，含20和40 wt%玻璃的复合材料具有较低的热膨胀系数和杨氏模数以及较低的介电性能，有望用于高温结构雷达罩。
A SiO2-Al2O3-CaO based glass was mixed with Al2O3at various ratios to fabricate composites for functional and structural applications such as substrate, low temperature co-fired ceramics and radomes, which necessitates a thorough characterization of mechanical, thermal and dielectric properties. The optimum densification temperatures decreased from 1350 °C (20 wt% glass) to 1200 °C (40 wt% glass), and to 850 °C (50–60 wt% glass) due to liquid phase sintering for the samples with 20 and 40 wt% glass, and viscous sintering for the samples with 50-60 wt% glass. Main phase was Al2O3as well as anorthite crystallized after 825 °C. Glass addition decreased the mechanical properties such as Young's modulus from 231 GPa (20 wt% glass) to 105 GPa (60 wt% glass), flexural strength from 387 MPa (20 wt% glass) and 213 MPa (60 wt% glass). Dielectric constant and dielectric loss of the composites with 20-60 wt% glass were 8.76–7.32 and 0.0022–0.0081 at 5 MHz, respectively. Thermal expansion coefficient also decreased with increasing glass content from 7.72 ppm/°C (20 wt% glass) to 6.66 ppm/°C (60 wt% glass). The composites with 50-60 wt% glass were suitable for substrate and low temperature co-fired ceramic applications due to lower densification temperatures (<950 °C), lower dielectric properties together with optimized mechanical and thermal properties. The composite with 55 wt% glass was then successfully fabricated by tape casting and co-fired with silver electrode, without any additional phase formation and shape distortion. In addition, the composites with 20 and 40 wt% glass were promising candidates for structural radome applications to be used at high temperatures due to their low thermal expansion coefficient and Young's modulus together with low dielectric properties.