Elimination of the orange-peel effect in arc-sprayed coatings

摘要

Like flame spraying, arc-spraying is a thermokinetic process for applying alloyed and unalloyed metals, and also pseudoalloys. The continuously fed spraying material may be used in the form of wire, insulated metal sheathed wire or flattened wire employing a bifilar system. The spraying material (spraying wire) reaches its liquidus at the short-circuit point of the arc. A spraying apparatus is required for the continuous process. As soon as the spraying wire fed in has reached its liquidus, it is atomised by atomising air or inert gas and the spraying particles produced acquire their direction of flight and kinetic energy, in addition to the internal energy already acquired. As a result of the atomisation, the particles acquire an irregular shape and are deformed into spheroids of varying size during their flight path while they are still in the molten state. Large spraying particles (drops) result in the orange-peel effect. This is due to the temperature difference at the positive and negative electrodes. Analogously, the spraying wire has to be fused more slowly at the low-temperature electrode than at the electrode with the higher temperature. According to the invention, this is also the basis of the claim. As a result of the kinetic and internal energy, the spheroids are deformed on striking a substrate so as to match the surface and form the deposit. Drawing for the abstract: in Figure 3, "diagrammatic... Original abstract incomplete.