Li He, Liu Yongsheng, Liu Yansong, Hu Kehui, Lu Zhigang, Liang Jingjing
Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
NPU-SAS Joint Research Center of Advanced Ceramics, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
ACS Omega. 2020 Oct 16;5(42):27455-27462. doi: 10.1021/acsomega.0c03944. eCollection 2020 Oct 27.
Solvents assist in the debinding of stereolithography-based 3D-printed alumina green bodies. The green bodies subsequently undergo thermal debinding and sintering to obtain alumina ceramics. In this study, several solvents were tested, including polyethylene glycol, oxalic acid, ammonium hydroxide, ethyl alcohol, methyl methacrylate, butyl acetate, dimethyl carbonate, methanol, ethyl acetate, and -butyl alcohol. The tested solvents during the debinding process showed different effects on microstructure and properties of 3D-printed alumina ceramics due to the variable aspects of their solubility toward the binders. The microstructure of the samples changed significantly after green bodies underwent solvent debinding, thermal debinding, and sintering, leading to loose spongy structures, porous aggregates, and compact structures, respectively. Shrinkage, bulk density, and open porosity changed slightly due to the debinding function of different solvents. Polyethylene glycol-impregnated samples displayed the minimum shrinkage in length direction (5.3%). Ethyl alcohol-impregnated sample showed minimum shrinkage in width (4.8%) and height (11.5%) directions. Ammonium hydroxide-impregnated samples exhibited minimum bulk density (2.8 g/cm) and maximum open porosity (28.3%). Dimethyl carbonate-impregnated samples presented minimum flexural strength (32.6 MPa), and oxalic acid-impregnated samples revealed maximum flexural strength (63.4 MPa). In sum, the as-obtained ceramics would be used as ceramic cores for hollow blades in aircraft engines due to their high open porosity and moderate flexural strength.
溶剂有助于基于立体光刻的3D打印氧化铝生坯脱脂。随后，生坯经过热脱脂和烧结以获得氧化铝陶瓷。在本研究中，测试了几种溶剂，包括聚乙二醇、草酸、氢氧化铵、乙醇、甲基丙烯酸甲酯、乙酸丁酯、碳酸二甲酯、甲醇、乙酸乙酯和正丁醇。由于脱脂过程中测试的溶剂对粘合剂的溶解性各不相同，它们对3D打印氧化铝陶瓷的微观结构和性能产生了不同的影响。生坯经过溶剂脱脂、热脱脂和烧结后，样品的微观结构发生了显著变化，分别导致了疏松的海绵状结构、多孔聚集体和致密结构。由于不同溶剂的脱脂作用，收缩率、体积密度和开孔率略有变化。聚乙二醇浸渍的样品在长度方向上的收缩率最小（5.3%）。乙醇浸渍的样品在宽度（4.8%）和高度（11.5%）方向上的收缩率最小。氢氧化铵浸渍的样品表现出最小的体积密度（2.8 g/cm³）和最大的开孔率（28.3%）。碳酸二甲酯浸渍的样品呈现出最小的抗弯强度（32.6 MPa），而草酸浸渍的样品则显示出最大的抗弯强度（63.4 MPa）。总之，所获得的陶瓷因其高开孔率和适中的抗弯强度，将用作航空发动机空心叶片的陶瓷型芯。
