Robocasting of alumina hollow filament lattice structures
Robocasting of alumina hollow filament lattice structures
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DOI：
10.1016/j.jeurceramsoc.2013.06.001
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发表时间：
2013-12-01
影响因子：
5.7
通讯作者：
Greil, Peter
中科院分区：
文献类型：
--
作者：
Schlordt, Tobias;Schwanke, Stanislaus;Greil, Peter
研究了用于制造具有周期性晶格结构的多孔陶瓷的水性胶体 α-Al2O3 凝胶的机器人控制沉积（机器人铸造）。该胶体凝胶负载有50 vol% α-Al2O3，表现出剪切稀化行为，剪切模量为288 kPa，屈服应力约为700 Pa。将外径为1.5 mm、毛细管直径为0.75 mm的圆形和矩形横截面的管状丝沉积在油浴中，制备具有自由跨度丝的网格桁架结构。冷冻干燥后，robocast 网格在空气中于 1550 摄氏度下烧结。X 射线 mu-CT 显示长距离（类似于 650 毫米）管状细丝的连续性。通过考虑中空丝内的膨胀应力和压力分布，讨论了避免毛细管塌陷的关键条件。在短丝长度下，由毛细管吸力驱动的油渗透到毛细管中支撑管状丝，而由工具喷嘴的移动驱动的油流导致压力差随着丝长度的增加而线性增加。 (C) 2013 Elsevier Ltd. 保留所有权利。
Robotic controlled deposition (robocasting) of an aqueous colloidal alpha-Al2O3 gel for manufacturing of cellular ceramics with periodical lattice structure was investigated. The colloidal gel was loaded with 50 vol% alpha-Al2O3 and exhibits shear-thinning behavior, a shear modulus of 288 kPa and a yield-stress of similar to 700 Pa. Tubular filaments of circular and rectangular cross section having an outer diameter of 1.5 mm and a capillary diameter of 0.75 mm were deposited in an oil bath to fabricate lattice truss structures with free spanning filaments. After freeze drying the robocast grids were sintered in air at 1550 degrees C. X-ray mu-CT revealed continuity of the tubular filaments for long distances (similar to 650 mm). Critical conditions to avoid capillary collapse were discussed by considering bulging stress and pressure distribution within the hollow filament. At short filament length oil infiltration into the capillary driven by capillary suction supports the tubular filament whereas oil flow driven by movement of the tool nozzle causes pressure difference to increase linearly with increasing filament length. (C) 2013 Elsevier Ltd. All rights reserved.