Ultra high temperature ceramics (UHTCs) ink with improved processability and dimensional control

A method for generating ultra-high loaded, ultra-high temperature ceramic (UHTC) ink for extrusion three-dimensional (3D) printing with enhanced shrinkage control, the method comprising:

• providing a ceramic powder in an amount of from 80 weight percent (wt %) to 95 wt % of the ink, the ceramic powder comprising a single-phase UHTC material;
• adding a plasticizer in an amount of from 1 wt % to 3 wt % of the ink;
• adding a dispersant in an amount of from 0.5 wt % to 1.5 wt % of the ink;
• and
• adding a solvent in an amount sufficient to form the ink such that it is stable and suitable for 3D printing,
• wherein the solvent is water, present in an amount of approximately 10 wt % of the ink.

A composition for generating ultra-high loaded, ultra-high temperature ceramics (UHTCs) ink for extrusion three-dimensional (3D) printing with enhanced shrinkage control, the composition comprising:

• a ceramic powder comprising a single-phase UHTC material;
• a plasticizer;
• a dispersant;
• and
• a solvent present in an amount sufficient to form the ink such that it is stable and suitable for 3D printing,
• wherein the ceramic powder is tantalum carbide (TaC) present in an amount of approximately 87 weight percent (wt %) of the composition,
• wherein the plasticizer is glycerol, present in an amount of approximately 2 wt % of the composition, having a purity of at least 99%, and being configured to reduce viscosity and enhance extrudability of the ink,
• wherein the dispersant is polyacrylic acid (PAA), present in an amount of approximately 1 wt % of the composition, having a molecular weight of at least 2000 grams per mole (g/mol), and being configured to disperse particles comprising the TaC via electrostatic repulsion and steric stabilization, thereby inhibiting agglomeration of the TaC,
• wherein the solvent is water, present in an amount of approximately 10 wt % of the composition,
• wherein the ink exhibits shear-thinning behavior and sufficient mechanical strength to enable shape retention post-extrusion during printing,
• wherein the ink is configured to be printable via direct ink writing, exhibiting consistent flow during extrusion and being free of nozzle clogging,
• wherein the ink is configured to produce stable extrusion under shear conditions and to inhibit backpressure-induced print defects, and
• wherein the ink is configured to print complex geometries including converging-diverging nozzle shapes.