基于浆料直写成形的多孔氧化铝陶瓷孔隙率与抗弯强度的相关性研究

Study on the Correlation between Porosity and Flexural Strength of Porous Alumina Ceramic Based on Direct Ink Writing Forming Method

浆料直写成形制备多孔氧化铝陶瓷的孔隙率和抗弯强度是一对具有负相关性的性能指标,但在保温隔热、过滤催化等领域需要制备高孔隙率、高抗弯强度的多孔陶瓷以满足服役要求。以挤出头内径、填充率、挤出丝层高/挤出头内径和打印速度四个关键工艺参数设计正交实验,通过对不同参数条件下成形的多孔陶瓷孔隙率和抗弯强度的测量与统计,分析了工艺参数对孔隙率和抗弯强度的影响规律,确定了孔隙率与抗弯强度的关联数学方程。结果表明,填充率对多孔陶瓷的孔隙率和抗弯强度影响最为显著,当填充率较小时,相邻挤出丝之间跨距较大,形成的宏观结构孔尺寸较大,此时样品的孔隙率大、强度低。当挤出头内径为0.41 mm、填充率为50%、挤出丝层高/挤出头内径为60%、打印速度为1200 mm/min时,陶瓷样件具有较高的孔隙率(66.32%±1.12%)和抗弯强度(10.54 MPa±0.32 MPa),且孔隙率和抗弯强度之间存在良好的相关性,实现了高孔隙率、高抗弯强度的多孔陶瓷制备,为3D打印成形高孔隙率和高强度的复杂多孔陶瓷提供了一定的参考依据。

The porosity and flexural strength of porous alumina ceramic fabricated by direct ink writing forming method is a pair of negatively correlated performance index.However,high porosity and high flexural strength are required in the fields of thermal insulation and filtration to meet their service demands.Orthogonal experiments are designed with four key process parameters:inner diameter of extrusion head,flling rate,extruded filament layer height/inner diameter of extrusion head and printing speed,then the influence mechanisms of different process parameters on the porosity and flexural strength are verified,and the correlation mathematical equation between the porosity and flexural strength is determined by the measurement and statistics of porosity and flexural strength of porous ceramics formed under different parameters.The experimental results show that the flling rate has the most significant effect on the porosity and flexural strength of porous alumina ceramics.And when the filling rate is small,the results of the span between adjacent extruded filaments is large,the formed macro-structure pore size and the porosity is large,however the flexural strength is small.When the inner diameter of the extrusion head is 0.41 mm,the filling rate is 50%,the extruded filament layer height/inner diameter of extrusion head is 60%,and the printing speed is 1200 mm/min,the formed ceramic sample meets a high porosity of 66.32%±1.12%and a flexural strength of 10.54 MPa±0.32 MPa,and the correlation between porosity and flexural strength.Finally,the preparation of porous ceramic with high porosity and high flexural strength is achieved,and a certain reference for complex porous ceramic structures with high porosity and high strength fabricated by 3D printing technology can be provided by the results.