Porous sintered metal bodies and methods of preparing porous sintered metal bodies

A method of forming a filter membrane by additive manufacturing steps, the method comprising:

• forming a first layer on a surface;
• forming a second layer over the first layer, the first and second layers comprising a feedstock, the feedstock containing metal particles, wherein the metal particles, measured in powder form, have a relative apparent density in a range from 5 to 25 percent of a theoretical density of the particles,
• wherein the theoretical density of the particles is a mass per volume of a single particle;
• and
• sintering the metal particles to form a porous sintered metal body, where the porous sintered metal body is a filter membrane containing from 20 to 50 percent metal particles by volume,
• wherein forming each of the first and second layers further comprises:
• selectively solidifying the feedstock at portions of each layer to form solidified feedstock, the portions in each layer containing from 20 to 50 percent of the metal particles by volume, and
• wherein sintering the metal particles further comprises:
• sintering the metal particles of the portions of each of the first and second layers to form the porous sintered metal body.