Experience in plasma production of hollow ceramic microspheres with required wall thickness

With the example of zirconium dioxide, a process for the plasma production of hollow spherical powders with controllable shell thickness has been studied. The formation of hollow microspheres, or microballoons, is achieved through melting of an initial porous powder in the plasma jet of a DC plasma gun. Hollow microballoons 40 to 125 μm in size with shell thickness 2 μm and over were obtained. The experience in measuring the characteristics of hollow microspheres, namely their sizes, density, and wall thickness, is outlined. A procedure for preliminary and final classification of powders which enables the production of spheres with desired volumetric density and wall thickness is proposed.