| 摘要 |
<p>The material from which the component was manufactured, is determined. All necessary preparation of the component is undertaken. A spraying material is selected. This has chemical-, physical- and mechanical properties comparable with those of the component itself. Coating parameters are selected to assure optimum bonding within the coating. Cold gas spraying is used to apply the coating. This replaces material removed by wear and preparation. Finishing treatment returns the coated component to its original geometry. Preparation first cleans the component, removing paint and soluble contaminants. The surface is removed, until there are no visible traces of wear or corrosion. Functional surfaces are then machined or otherwise treated to produce the required form and surface structure. Treated surfaces are sealed. They are painted, anodized or chromatized (passivation). The re-manufactured surface is subjected to anodic oxidation in chromic or sulfuric acid. The oxide layer produced is 3-4 mu m thick. For pre- and final treatment, electrochemical processes, spark erosion or laser processing are used. During cold spraying, material is deposited uniformly over the relevant area, its thickness at least replacing the previous wear. The coating thickness corresponds with local variations in the depth of wear. The composition of the coating is the same as that of the component, or differs, whilst having comparable chemical-, physical- or mechanical properties. Before coating, no mechanical activation takes place, e.g. by corundum-blasting. Additional overcoating may be applied, to protect from wear, corrosion or other damaging influences, using thermal- and electroplating processes. An indicator of the bonding quality achieved, is the fatigue strength of the layer, as demonstrated by endurance testing. The component is a running gear component; it is a propellor blade. During preparation, worn and/or corroded surfaces are removed to a depth of 0.1 - 0.8 mm. During cold spraying, a large proportion of the sides of the propellor blade experiencing reduced and increased pressures, are coated.</p> |
