(536l) Manufacture of Complex-Shaped Tungsten Materials Via Atomic Layer Deposition and Direct Ink Writing
AIChE Annual Meeting
Wednesday, November 16, 2022 - 3:30pm to 5:00pm
In this work we propose the use of direct ink writing (DIW) of W and W alloys to fabricate complex shaped components with near full density, high yield strength, and low surface roughness. Further, we utilize atomic layer deposition (ALD) to deposit sintering aids and dopants at low loading directly on the particle surface. A tungsten-based colloidal ink was formulated with an optimized solids fraction volume loading. The ink was then continuously extruded through a nozzle which enables bottom-up fabrication of the desired geometry, such as cylinders or lattices for testing. A design of experiments (DOE) was employed to optimize printing parameters in order to mitigate surface roughness and maintain print uniformity. The green bodies were dried and sintered at 1600°C in a low hydrogen atmosphere. Surface profilometry was used to obtain the sintered surface roughness and evaluate the DOE. The optimized printing parameters were employed to manufacture samples with various sintering aids and dopants, added through conventional mixing or ALD on the powder prior to ink formation. A secondary DOE was employed to evaluate the parameters that affect the final print density. The systematic optimization of the colloidal ink resulted in parts that demonstrated both densification and stability in complex geometry. Addition of the sintering aids promoted densification further at the lower sintering temperature and ALD was shown to be a successful loading method. This work introduces the use of ALD-functionalized W in colloidal gels for the purpose of DIW complex shapes.