Abstract: An apparatus for forming ceramic or metal powders has a plasma generator, a source of material in the form of powder particles and a projection torch for passing the material through the plasma to melt the powder particles and then projecting a stream of plasma and material via an outlet. A container is provided for containing the projected stream. A plurality of spray diffusers are arranged to diffuse a spray of cryogenic liquid into a space through which the projected stream travels, whereby the projected stream is quenched. A console controls the flow rates of the powder particles and the plasma into the projection torch.

Abstract: A process is disclosed for the densification of a porous structure. The structure is immersed in a liquid hydrocarbon and is heated by induction so as to form, by decomposition of the hydrocarbon, carbon or pyrolytic graphite which can be deposited in the pores or cavities of the structure. The process may be used for the densification of fabrics or felts for use in pads in disc brakes.