Interfacial microstructure characterization and strength evaluation of Si3N4/Si3N4 joints with Si-Mg composite filler for high-temperature applications
Interfacial microstructure characterization and strength evaluation of Si3N4/Si3N4 joints with Si-Mg composite filler for high-temperature applications
复制标题
高温应用中含有 Si-Mg 复合填料的 Si3N4/Si3N4 接头的界面微观结构表征和强度评估
DOI：
10.1016/j.ceramint.2021.04.252
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发表时间：
2021
影响因子：
5.2
通讯作者：
Kazuyuki Kohama
中科院分区：
文献类型：
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作者：
Kazuyuki Kohama
在真空下在1100 °C下使用Mg含量（XMg）范围为0原子%的Si-Mg复合填料将氮化硅（Si 3 N4）部件接合10分钟。至59原子%。Si 3 N4/Si 3 N4接头的制备是通过在接头界面形成Si层实现的;熔融的Si-Mg液态经Mg蒸发诱导等温凝固后转变为固态Si层。当XMg超过液相线成分37 at.%时，接头室温抗拉强度显著提高这是因为Si层的致密化/减薄增强。在这些情况下，一些Mg原子与Si 3 N4反应形成细晶MgSiN 2基层，而在Si层中观察到相对较大（>0.1 μm）和较小（<10 nm）的MgO沉淀物。在高XMg时，MgO沉淀物呈网状排列，提高了Si层的断裂强度。在1200 °C的空气中使用三点弯曲测试检查了在室温下具有高强度的接头，并承受了约200 MPa的最大断裂应力，这证实了它们在比粘合温度高至少100 °C的氧化气氛中使用的潜力。
Silicon-nitride (Si3N4) components were joined under vacuum at 1100 °C for 10 min using Si–Mg composite fillers with Mg contents (XMg) that ranged from 0 at.% to 59 at.%. The Si3N4/Si3N4joints were fabricated via Si layer formation at the joint interface; the molten Si–Mg liquid was transformed into a solid Si layer after Mg-evaporation-induced isothermal solidification. The joint tensile strength at room temperature increased considerably whenXMgexceeded the liquidus composition of 37 at.% because of the enhanced densification/thinning of the Si layer. In these cases, some Mg atoms reacted with Si3N4to form a fine-grained MgSiN2-based layer, whereas relatively large (>0.1 μm) and smaller MgO precipitates (<10 nm) were observed in the Si layer. At a highXMg, the MgO precipitates were arranged in a network-like structure, which improved the fracture strength of the Si layer. The joints with a high strength at room temperature were examined using a three-point bending test at 1200 °C in air and endured a maximum fracture stress of ~200 MPa, which confirmed their potential for use in oxidizing atmospheres at least 100 °C above the bonding temperature.