Wang Shuangxi, Lan Haifeng, Wang Wenjun, Liu Gaoshan, Zhang Dan
College of Engineering, Shantou University, Shantou 515063, China.
Materials (Basel). 2018 Aug 20;11(8):1477. doi: 10.3390/ma11081477.
Ceramic-Al substrates with co-continuous ceramic and metal phases, which exhibit high thermal conductivity and compatible coefficient of thermal expansion (CTE), have been widely investigated through the process of die-casting. In this research, a kind of powder sintering process was proposed for fabricating ceramic-Cu composite substrates with co-continuous phases. Copper fiber (Cu) has excellent thermal conductivity and large aspect ratio, making it an ideal material to form bridging network structures in the ceramic-Cu composite. To maintain the large aspect ratio of Cu, and densify the composite substrate, ZnO-SiO₂-CaO glass was introduced as a sintering additive. Both Al₂O₃/glass/Cu and Al₂O₃/30glass/Cu composite substrates were hot-pressed at 850 °C under 25 MPa. Experimental results showed that the thermal conductivity of Al₂O₃/30glass/30Cu composite substrate was as high as 38.9 W/mK, which was about 6 times that of Al₂O₃/30glass; in contrast, the thermal conductivity of Al₂O₃/30glass/30Cu composite substrate was only 25.9 W/mK. Microstructure observation showed that, influenced by hot press and corrosion of molten ZnO-SiO₂-CaO glass, the copper fibers were deformed under hot-pressing, and some local melting-like phenomena occurred on the surface of copper fiber at 850 °C under 25 MPa. The molten phase originating from surface of Cu welded the overlapping node of copper fibers during cooling process. Finally, the interconnecting metal bridging in ceramic matrix was formed and behaved as a rapid heat-dissipating channel, which is similar to substrates prepared through die-casting process by porous ceramic and melted Al.
具有共连续陶瓷相和金属相的陶瓷 - 铝基板，因其具有高导热性和热膨胀系数（CTE）兼容性，已通过压铸工艺得到广泛研究。本研究提出了一种粉末烧结工艺来制备具有共连续相的陶瓷 - 铜复合基板。铜纤维（Cu）具有优异的导热性和大长径比，使其成为在陶瓷 - 铜复合材料中形成桥接网络结构的理想材料。为了保持铜的大长径比并致密化复合基板，引入了ZnO - SiO₂ - CaO玻璃作为烧结添加剂。Al₂O₃/玻璃/Cu和Al₂O₃/30玻璃/Cu复合基板均在850℃、25MPa下进行热压。实验结果表明，Al₂O₃/30玻璃/30Cu复合基板的热导率高达38.9W/mK，约为Al₂O₃/30玻璃的6倍；相比之下，Al₂O₃/30玻璃/30Cu复合基板的热导率仅为25.9W/mK。微观结构观察表明，受热压和熔融ZnO - SiO₂ - CaO玻璃腐蚀的影响，铜纤维在热压过程中发生变形，在850℃、25MPa下铜纤维表面出现一些局部类似熔化的现象。Cu表面产生的熔融相在冷却过程中焊接了铜纤维的重叠节点。最终，在陶瓷基体中形成了相互连接的金属桥接，其作为快速散热通道，类似于通过多孔陶瓷和熔化铝的压铸工艺制备的基板。
