Orientation and Adhesion of Particles

The high adhesion of electrostatically deposited dust as compared to a mechanically pressed sample has been attributed to dipole characteristics of particles and alignment by the field. Recent tests show that if the dust is deposited as single particles and without an electric field a high adhesion is obtained. Other tests indicate that some particles behave like dipoles but most particles appear to have multiple positive and negative areas so that alignment by the field is limited. It appears that the high adhesion is due to Coulomb forces between adjacent particles but that an individual particle arriving at a surface can align itself without the aid of an external field.