Abstract: Method and device for suspending an ultrafine powder in a gas wherein a mass of powder to be dispersed in enclosing in a container between an axially movable piston and an axially fixed member adjacent to the ends of the container. The fixed member defines an inner counteracting surface facing the powder to be dispersed and has a peripheral gas inlet passage adjacent to the wall of the container and an axial passage extending out of a first end of the container. The second end of the container has a gas inlet. A first gas flow is injected into the second end of the container to move the piston towards the fixed member, thereby pressing the powder against the counteracting surface of the fixed member. A second gas flows into the first end of the container through the peripheral passage for eroding the powder adjacent to the counteracting surface and driving the eroded powder through the axial passage out of the container.