Abstract: A three-dimensional printing kit can include a particulate build material, a binding agent, and a supportive coating agent. The particulate build material can include from about 80 wt % to about 100 wt % metal particles based on the total weight of the particulate build material. The binding agent can include binder particles dispersed in a binder liquid vehicle. The supportive coating agent can include ceramic particles having a negative coefficient of thermal expansion, a gelling compound, and a supportive coating liquid vehicle.

Abstract: A method of three-dimensional printing can include iteratively applying metal particles having a heat fusion temperature as individual build material layers, and based on a 3D object model, iteratively and selectively applying a metallic binding agent onto the individual build material layers so that the individual build material layers are built up and bound together to form a green-body object. The metallic binding agent includes an aqueous liquid vehicle and metal salt or metal oxide nanoparticles that are thermally reducible to a metal or metal alloy at an elevated metal reducing temperature that is lower than the heat fusion temperature. The method also includes iteratively and selectively applying a polymeric binding agent onto the individual build material layers at an interface between the green-body object and a support structure for the green-body object, leaving a residue at the interface.

Abstract: Examples of lattice structures are described herein. In some examples, a heat exchanger may include a three-dimensional (3D) lattice structure. In some examples, the heat exchanger may include a spiral structure transecting the 3D lattice structure. In some examples, the spiral structure is to mix fluid to pass through the 3D lattice structure.

Abstract: In one example in accordance with the present disclosure, an additive manufacturing system is described. The additive manufacturing system includes an additive manufacturing device to form a three-dimensional (3D) printed object with regions of differing porosity. The additive manufacturing system also includes a controller to form the 3D printed object. Specifically, by controlling ejection of a first binding agent onto a porous region and a non-porous region of the 3D printed object and controlling ejection of a second binding agent onto the non-porous region of the 3D printed object.

Abstract: A three-dimensional (3D) printing system may include a build volume, a slurry reservoir to contain a slurry of build material and liquid, and a slurry dispenser to receive the slurry from the slurry reservoir and movable in a direction across the build volume to dispense slurry across the build volume.

Abstract: A three-dimensional printing kit can include a particulate build material, a binding agent, and a supportive coating agent. The particulate build material can include from about 80 wt % to about 100 wt % metal particles based on the total weight of the particulate build material. The binding agent can include binder particles dispersed in a binder liquid vehicle. The supportive coating agent can include ceramic particles having a negative coefficient of thermal expansion, a gelling compound, and a supportive coating liquid vehicle.