Properties of Al2O3 Pastes Using Inorganic Na2SiO3 Binder and Organic Binder for Direct Ink Writing

The direct ink writing (DIW)‐type 3D printing technology has advantages of manufacturing complicated ceramic objects with short time and low cost. In the DIW, ceramic pastes are extruded through a nozzle. Therefore, rheological properties of ceramic pastes and writing conditions are crucial to obtain desired ceramic objects. Organic binder such as polyvinylpyrrolidone (PVP) and polyvinyl alcohol has been used for ceramic pastes of DIW, however, they involve relatively high material cost (a few hundreds $/kg). On the other hand, inorganic binder Na 2 SiO 3 has much lower material cost than the organic binders (70 $/kg). Herein, the compatibility of the inorganic binder with ceramic paste for DIW is investigated. Line patterns are prepared by using Al 2 O 3 ‐based paste with inorganic (Na 2 SiO 3 ) and organic PVP binders by DIW. Same size of line patterns is obtained from both pastes. Also, both line patterns do not peel off after sonication for 30 min, indicating the line patterns are highly stable. Material costs in the inorganic paste are 10% lower than those of the organic paste. Na 2 SiO 3 inorganic binder is a promising binder because of high compatibility with DIW and low cost.