3D printing high density ceramics using binder jetting with nanoparticle densifiers

Abstract

This study examines the effects of nanoparticle densifiers added to printing liquid on the mechanical performance and manufacturability of ceramics made using binder jetting. “Green” alumina samples were synthesized with filler particles of average particle size 40 μm embedded with nanoparticles of average size of 50 nm suspended in the printing liquid with varying concentration of 0–15 wt%. Samples were characterized for density, porosity, compressive strength, and printing liquid penetration depth in the filler powder layer assessed using surface tension testing. Results showed that the presence of the nanoparticle had a marked effect on the physical and mechanical properties of the samples whose relative density increased by about 30%. MicroCT imaging of the samples showed a decrease in interparticle pores with an addition of 15 wt% alumina nanoparticles. Compressive strength improved by 743%, from 76 kPa to 641 kPa as the densifier content was increased from 0 to 15 wt%. Surface tension of the printing liquid decreased from 44 mN/m to 23 mN/m with increasing densifier concentration from 0 to 15 wt% indicating that the penetration depth of the printing liquid would decrease with increasing densifier content. Implications of this approach on high density ceramic part printing efficiency are discussed in detail.