Three-dimensional (3D) printing with a sintering aid/fixer fluid and a liquid functional material

A three-dimensional (3D) printing method, comprising:

• forming a green body with multiple layers, each of the multiple layers being formed by:
• applying ceramic build material;
• and
• patterning the ceramic build material by:
• applying a liquid functional material, including an anionically stabilized susceptor material selected from the group consisting of a carbon black particle having negatively charged groups at a surface of the carbon black particle, a carbon black particle having a negatively charged polymeric dispersant absorbed to a surface thereof, a ferromagnetic metal oxide particle having an anionic dispersing species absorbed to a surface thereof, a semiconductor or conductive oxide particle having an anionic dispersing species absorbed to a surface thereof, and combinations thereof, to a portion of the ceramic build material;
• and
• applying a sintering aid/fixer fluid, including a cationically stabilized amphoteric alumina particulate material, to the portion of the ceramic build material,
• the applied anionically stabilized susceptor material and the applied cationically stabilized amphoteric alumina particulate material reacting to immobilize and prevent the spreading of both materials outside the portion, and the applied cationically stabilized amphoteric alumina particulate material filling at least some voids between the ceramic build material;
• and
• heating the green body using microwave radiation, radio frequency radiation, or thermal energy, thereby sintering the ceramic build material and the applied cationically stabilized amphoteric alumina particulate material of the green body to form a part.

A three-dimensional (3D) printing system, comprising:

• a supply of ceramic build material;
• a build material distributor;
• a supply of a liquid functional material including an anionically stabilized susceptor material selected from the group consisting of a carbon black particle having negatively charged groups at a surface of the carbon black particle, a carbon black particle having a negatively charged polymeric dispersant absorbed to a surface thereof, a ferromagnetic metal oxide particle having an anionic dispersing species absorbed to a surface thereof, a semiconductor or conductive oxide particle having an anionic dispersing species absorbed to a surface thereof, and combinations thereof;
• a supply of a sintering aid/fixer fluid including a cationically stabilized amphoteric alumina particulate material;
• respective applicators for selectively dispensing the liquid functional material and the sintering aid/fixer fluid;
• a controller;
• and
• a non-transitory computer readable medium having stored thereon computer executable instructions to cause the controller to:
• utilize the build material distributor to dispense a layer of the ceramic build material;
• and
• utilize the applicators to simultaneously or sequentially dispense the liquid functional material and the sintering aid/fixer fluid onto a portion of the layer of the ceramic build material such that at least some of the anionically stabilized susceptor material reacts with at least some of the cationically stabilized amphoteric alumina particulate material to immobilize and prevent the spreading of both materials outside the portion.